title:
Characteristic Initial Value Problem for Spherically Symmetric
  Barotropic Flow

abstract:
  We study the equations of motion for a barotropic fluid in spherical
symmetric flow. Making use of the Riemann invariants we consider the
characteristic form of these equations. In a first part, we show that the
resulting constraint equations along characteristics can be solved globally
away from the center of symmetry. In a second part, given data on two
intersecting characteristics, we show existence and uniqueness of a smooth
solution in a neighborhood in the future of these characteristics.


title:
Datta-and-Das spin transistor controlled by a high-frequency
  electromagnetic field

abstract:
  We developed the theory of spin dependent transport through a spin-modulator
device (so-called Datta-and-Das spin transistor) in the presence of a
high-frequency electromagnetic field (dressing field). Solving the
Schr\"odinger problem for dressed electrons, we demonstrated that the field
drastically modifies the spin transport. In particular, the dressing field
leads to renormalization of spin-orbit coupling constants that varies
conductivity of the spin transistor. The present effect paves the way for
controlling the spin-polarized electron transport with light in prospective
spin-optronic devices.


title:
Reversibility of Linear Cellular Automata on Cayley Trees with Periodic
  Boundary Condition

abstract:
  While one-dimensional cellular automata have been well studied, there are
relatively few results about multidimensional cellular automata; the
investigation of cellular automata defined on Cayley trees constitutes an
intermediate class. This paper studies the reversibility of linear cellular
automata defined on Cayley trees with periodic boundary condition, where the
local rule is given by $f(x_0, x_1, \ldots, x_d) = b x_0 + c_1 x_1 + \cdots +
c_d x_d \pmod{m}$ for some integers $m, d \geq 2$. The reversibility problem
relates to solving a polynomial derived from a recurrence relation, and an
explicit formula is revealed; as an example, the complete criteria of the
reversibility of linear cellular automata defined on Cayley trees over
$\mathbb{Z}_2$, $\mathbb{Z}_3$, and some other specific case are addressed.
Further, this study achieves a possible approach for determining the
reversibility of multidimensional cellular automata, which is known as a
undecidable problem.


title: Polar compensation at the surface of SrTiO3 (111)

abstract:
  We have systematically investigated the annealing effect on the structure and
composition of the polar surface of SrTiO3 (111), starting with an ex-situ
chemical etch. The relative surface concentration between Ti and Sr strongly
depends on both the annealing temperature and the oxygen processing. There is a
critical annealing temperature at which the maximum concentration ratio of Ti
to Sr is achieved, while still maintaining a (1 x 1) surface structure. We
demonstrate that with proper processing it is possible to avoid surface
reconstruction over a broad temperature range. Our results provide an optimal
temperature window for epitaxial film growth.


title: A single-phase, proximal path-following framework

abstract:
  We propose a new proximal, path-following framework for a class of
constrained convex problems. We consider settings where the nonlinear---and
possibly non-smooth---objective part is endowed with a proximity operator, and
the constraint set is equipped with a self-concordant barrier. Our approach
relies on the following two main ideas. First, we re-parameterize the
optimality condition as an auxiliary problem, such that a good initial point is
available; by doing so, a family of alternative paths towards the optimum is
generated. Second, we combine the proximal operator with path-following ideas
to design a single-phase, proximal, path-following algorithm. Our method has
several advantages. First, it allows handling non-smooth objectives via
proximal operators; this avoids lifting the problem dimension in order to
accommodate non-smooth components in optimization. Second, it consists of only
a \emph{single phase}: While the overall convergence rate of classical
path-following schemes for self-concordant objectives does not suffer from the
initialization phase, proximal path-following schemes undergo slow convergence,
in order to obtain a good starting point \cite{TranDinh2013e}. In this work, we
show how to overcome this limitation in the proximal setting and prove that our
scheme has the same $\mathcal{O}(\sqrt{\nu}\log(1/\varepsilon))$ worst-case
iteration-complexity with standard approaches \cite{Nesterov2004,Nesterov1994}
without requiring an initial phase, where $\nu$ is the barrier parameter and
$\varepsilon$ is a desired accuracy. Finally, our framework allows errors in
the calculation of proximal-Newton directions, without sacrificing the
worst-case iteration complexity. We demonstrate the merits of our algorithm via
three numerical examples, where proximal operators play a key role.


title: Frequent-Itemset Mining using Locality-Sensitive Hashing

abstract:
  The Apriori algorithm is a classical algorithm for the frequent itemset
mining problem. A significant bottleneck in Apriori is the number of I/O
operation involved, and the number of candidates it generates. We investigate
the role of LSH techniques to overcome these problems, without adding much
computational overhead. We propose randomized variations of Apriori that are
based on asymmetric LSH defined over Hamming distance and Jaccard similarity.


title: Dielectric constant of water in the interface

abstract:
  We define the dielectric constant (susceptibility) that should enter the
Maxwell boundary value problem when applied to microscopic dielectric
interfaces. The dielectric constant (susceptibility) of the interface is
defined by exact linear-response equations involving correlations of
statistically fluctuating interface polarization and the Coulomb interaction
energy of external charges with the dielectric. The theory is applied to the
interface between water and spherical solutes of altering size studied by
molecular dynamics (MD) simulations. The effective dielectric constant of
interfacial water is found to be significantly lower than its bulk value, and
it also depends on the solute size. For TIP3P water used in MD simulations the
interface dielectric constant changes from 9 to 4 when the effective solute
radius is increased from ~5 to 18 A.


title:
Saliency Detection combining Multi-layer Integration algorithm with
  background prior and energy function

abstract:
  In this paper, we propose an improved mechanism for saliency detection.
Firstly,based on a neoteric background prior selecting four corners of an image
as background,we use color and spatial contrast with each superpixel to obtain
a salinecy map(CBP). Inspired by reverse-measurement methods to improve the
accuracy of measurement in Engineering,we employ the Objectness labels as
foreground prior based on part of information of CBP to construct a
map(OFP).Further,an original energy function is applied to optimize both of
them respectively and a single-layer saliency map(SLP)is formed by merging the
above twos.Finally,to deal with the scale problem,we obtain our multi-layer
map(MLP) by presenting an integration algorithm to take advantage of multiple
saliency maps. Quantitative and qualitative experiments on three datasets
demonstrate that our method performs favorably against the state-of-the-art
algorithm.


title: Mathematical analysis of historical income per capita distributions

abstract:
  Data describing historical growth of income per capita [Gross Domestic
Product per capita (GDP/cap)] for the world economic growth and for the growth
in Western Europe, Eastern Europe, Asia, former USSR, Africa and Latin America
are analysed. They follow closely the linearly-modulated hyperbolic
distributions represented by the ratios of hyperbolic distributions obtained by
fitting the GDP and population data. Results of this analysis demonstrate that
income per capita was increasing monotonically. There was no stagnation and
there were no transitions from stagnation to growth. The usually postulated
dramatic escapes from the Malthusian trap never happened because there was no
trap. Unified Growth Theory is fundamentally incorrect because its central
postulates are contradicted repeatedly by data, which were used but never
analysed during the formulation of this theory. The large body of
readily-available data opens new avenues for the economic and demographic
research. They show that certain fundamental postulates revolving around the
concept of Malthusian stagnation need to be replaced by the evidence-based
interpretations. Within the range of analysable data, which for the growth of
population extends down to 10,000 BC, growth of human population and economic
growth were hyperbolic. There was no Malthusian stagnation and there were no
transitions to distinctly faster trajectories. Industrial Revolution had no
impact on changing growth trajectories.


title:
Formation of field induced absorption in the probe response signal of a
  four-level V type atomic system a theoretical study

abstract:
  A density matrix based analytical model is developed to study the coherent
probe field propagation through a four-level V type system in presence of a
coherent control field. The model allows coupling of the probe field from the
upper ground level to both of the excited levels keeping the control field
locked to a particular transition. The addition of an extra ground level to a
conventional three-level V type system creates extra decay paths to the ground
levels for the upper level population. A set of sixteen density matrix based
equations are formed and then solved analytically under rotating wave
approximation to study the probe response under steady state condition. The
simulated probe absorption spectra shows absorption dip at the centre of a
transparency window only under Doppler broadened condition although the
conventional EIT window appears under Doppler free condition. The dependence of
the field induced absorption signal on the Rabi frequency of the control field,
population transfer rate among the ground levels and temperature of the vapour
medium has been studied in details.


title: The $1$-Laplacian Cheeger Cut: Theory and Algorithms

abstract:
  This paper presents a detailed review of both theory and algorithms for the
Cheeger cut based on the graph $1$-Laplacian. In virtue of the cell structure
of the feasible set, we propose a cell descend (CD) framework for achieving the
Cheeger cut. While plugging the relaxation to guarantee the decrease of the
objective value in the feasible set, from which both the inverse power (IP)
method and the steepest descent (SD) method can also be recovered, we are able
to get two specified CD methods. Comparisons of all these methods are conducted
on several typical graphs.


title:
Correlation between non-centrosymmetry and superconductivity in
  quasi-one-dimensional compounds A2Cr3As3 (A=K, Rb)

abstract:
  Non-centrosymmetric superconductors, whose crystal structure is absent of
inversion symmetry, have recently received special attentions due to the
expectation of unconventional pairings and exotic physics associated with such
pairings. The newly discovered superconductors A2Cr3As3 (A=K, Rb), featured by
the quasi-one dimensional structure with conducting CrAs chains, belongs to
such kind of superconductor. In this study, we are the first to report the
finding that the superconductivity of A2Cr3As3 (A=K, Rb) has a positive
correlation with the extent of non-centrosymmetry. Our in-situ high pressure ac
susceptibility and synchrotron x-ray diffraction measurements reveal that the
larger bond angle of As-Cr-As in the CrAs chains can be taken as a key factor
controlling superconductivity. While the smaller bond angle and the distance
between the CrAs chains also affect the superconductivity due to their
structural connections with the angle. We find that the larger value of the
difference between the larger and samller angles, which is associated with the
extent of the non-centrosymmetry of the lattice structure, is in favor of
superconductivity. These results are expected to shed a new light on the
underlying mechanism of the superconductivity in these Q1D superconductors and
also to provide new perspective in understanding other non-centrosymmetric
superconductors.


title:
An optimal method for scheduling observations of large sky error regions
  for finding optical counterparts to transients

abstract:
  The discovery and subsequent study of optical counterparts to transient
sources is crucial for their complete astrophysical understanding. Various
gamma ray burst (GRB) detectors, and more notably the ground--based
gravitational wave detectors, typically have large uncertainties in the sky
positions of detected sources. Searching these large sky regions spanning
hundreds of square degrees is a formidable challenge for most ground--based
optical telescopes, which can usually image less than tens of square degrees of
the sky in a single night. We present algorithms for optimal scheduling of such
follow--up observations in order to maximize the probability of imaging the
optical counterpart, based on the all--sky probability distribution of the
source position. We incorporate realistic observing constraints like the
diurnal cycle, telescope pointing limitations, available observing time, and
the rising/setting of the target at the observatory location. We use
simulations to demonstrate that our proposed algorithms outperform the default
greedy observing schedule used by many observatories. Our algorithms are
applicable for follow--up of other transient sources with large positional
uncertainties, like Fermi--detected GRBs, and can easily be adapted for
scheduling radio or space--based X--ray followup.


title: Numerical simulations of downward convective overshooting in giants

abstract:
  An attempt at understanding downward overshooting in the convective envelopes
of post-main-sequence stars has been made on the basis of three-dimensional
large-eddy simulations, using artificially modified OPAL opacity and taking
into account radiation and ionization in the equation of state. Two types of
star, an intermediate-mass star and a massive star, were considered. To avoid a
long thermal relaxation time of the intermediate-mass star, we increased the
stellar energy flux artificially while trying to maintain a structure close to
the one given by a 1D stellar model. A parametric study of the flux factor was
performed. For the massive star, no such process was necessary. Numerical
results were analysed when the system reached the statistical steady state. It
was shown that the penetration distance in pressure scaleheights is of the
order of unity. The scaling relations between penetration distance, input flux
and vertical velocity fluctuations studied by Singh et al. were checked. The
anisotropy of the turbulent convection and the diffusion models of the
third-order moments representing the non-local transport were also
investigated. These models are dramatically affected by the velocity fields and
no universal constant parameters seem to exist. The limitations of the
numerical results were also discussed.


title:
New complex analytic methods in the study of non-orientable minimal
  surfaces in $\mathbb{R}^n$

abstract:
  The aim of this work is to adapt the complex analytic methods originating in
modern Oka theory to the study of non-orientable conformal minimal surfaces in
$\mathbb{R}^n$ for any $n\ge 3$. These methods, which we develop essentially
from the first principles, enable us to prove that the space of conformal
minimal immersions of a given bordered non-orientable surface to $\mathbb{R}^n$
is a real analytic Banach manifold, obtain approximation results of
Runge-Mergelyan type for conformal minimal immersions from non-orientable
surfaces, and show general position theorems for non-orientable conformal
minimal surfaces in $\mathbb{R}^n$. We also give the first known example of a
properly embedded non-orientable minimal surface in $\mathbb{R}^4$; a Mobius
strip.
  All our new tools mentioned above apply to non-orientable minimal surfaces
endowed with a fixed choice of a conformal structure. This enables us to obtain
significant new applications to the global theory of non-orientable minimal
surfaces. In particular, we construct proper non-orientable conformal minimal
surfaces in $\mathbb{R}^n$ with any given conformal structure, complete
non-orientable minimal surfaces in $\mathbb{R}^n$ with arbitrary conformal type
whose generalized Gauss map is nondegenerate and omits $n$ hyperplanes of
$\mathbb{CP}^{n-1}$ in general position, complete non-orientable minimal
surfaces bounded by Jordan curves, and complete proper non-orientable minimal
surfaces normalized by bordered surfaces in $p$-convex domains of
$\mathbb{R}^n$.


title: Elastic turbulence in a shell model of polymer solution

abstract:
  We show that, at low inertia and large elasticity, shell models of
viscoelastic fluids develop a chaotic behaviour with properties similar to
those of elastic turbulence. The low dimensionality of shell models allows us
to explore a wide range both in polymer concentration and in Weissenberg
number. Our results demonstrate that the physical mechanisms at the origin of
elastic turbulence do not rely on the boundary conditions or on the geometry of
the mean flow.


title: Dessins on Modular Curves

abstract:
  Given a finite index subgroup $\Gamma$ of ${\rm{PSL}}_2(\Bbb{Z})$, we
investigate Belyi functions on the corresponding modular curve $X(\Gamma)$ by
introducing two methods for constructing such functions. Numerous examples have
been worked out completely and as an application, we have derived modular
equations for $\Gamma_0(2),\Gamma_0(3)$ and several special values of the
$j$-function by a new method based on the theory of Belyi functions and dessin
d'enfants.


title:
Intracell Interference Characterization and Cluster Inference for D2D
  Communication

abstract:
  The homogeneous poisson point process (PPP) is widely used to model temporal,
spatial or both topologies of base stations (BSs) and mobile terminals (MTs).
However, negative spatial correlation in BSs, due to strategical deployments,
and positive spatial correlations in MTs, due to homophilic relations, cannot
be captured by homogeneous spatial PPP (SPPP). In this paper, we assume doubly
stochastic poisson process, a generalization of homogeneous PPP, with intensity
measure as another stochastic process. To this end, we assume Permanental Cox
Process (PCP) to capture positive spatial correlation in MTs. We consider
product density to derive closed-form approximation (CFA) of spatial summary
statistics. We propose Euler Characteristic (EC) based novel approach to
approximate intractable random intensity measure and subsequently derive
nearest neighbor distribution function. We further propose the threshold and
spatial extent of excursion set of chi-square random field as interference
control parameters to select different cluster sizes for device-to-device (D2D)
communication. The spatial extent of clusters is controlled by nearest neighbor
distribution function which is incorporated into Laplace functional of SPPP to
analyze the effect of D2D interfering clusters on average coverage probability
of cellular user. The CFA and empirical results are in good agreement and its
comparison with SPPP clearly shows spatial correlation between D2D nodes.


title:
Underwater Fish Tracking for Moving Cameras based on Deformable Multiple
  Kernels

abstract:
  Fishery surveys that call for the use of single or multiple underwater
cameras have been an emerging technology as a non-extractive mean to estimate
the abundance of fish stocks. Tracking live fish in an open aquatic environment
posts challenges that are different from general pedestrian or vehicle tracking
in surveillance applications. In many rough habitats fish are monitored by
cameras installed on moving platforms, where tracking is even more challenging
due to inapplicability of background models. In this paper, a novel tracking
algorithm based on the deformable multiple kernels (DMK) is proposed to address
these challenges. Inspired by the deformable part model (DPM) technique, a set
of kernels is defined to represent the holistic object and several parts that
are arranged in a deformable configuration. Color histogram, texture histogram
and the histogram of oriented gradients (HOG) are extracted and serve as object
features. Kernel motion is efficiently estimated by the mean-shift algorithm on
color and texture features to realize tracking. Furthermore, the HOG-feature
deformation costs are adopted as soft constraints on kernel positions to
maintain the part configuration. Experimental results on practical video set
from underwater moving cameras show the reliable performance of the proposed
method with much less computational cost comparing with state-of-the-art
techniques.


title:
A Feature Learning and Object Recognition Framework for Underwater Fish
  Images

abstract:
  Live fish recognition is one of the most crucial elements of fisheries survey
applications where vast amount of data are rapidly acquired. Different from
general scenarios, challenges to underwater image recognition are posted by
poor image quality, uncontrolled objects and environment, as well as difficulty
in acquiring representative samples. Also, most existing feature extraction
techniques are hindered from automation due to involving human supervision.
Toward this end, we propose an underwater fish recognition framework that
consists of a fully unsupervised feature learning technique and an
error-resilient classifier. Object parts are initialized based on saliency and
relaxation labeling to match object parts correctly. A non-rigid part model is
then learned based on fitness, separation and discrimination criteria. For the
classifier, an unsupervised clustering approach generates a binary class
hierarchy, where each node is a classifier. To exploit information from
ambiguous images, the notion of partial classification is introduced to assign
coarse labels by optimizing the "benefit" of indecision made by the classifier.
Experiments show that the proposed framework achieves high accuracy on both
public and self-collected underwater fish images with high uncertainty and
class imbalance.


title: Ramsey numbers of $4$-uniform loose cycles

abstract:
  Gy\'arf\'as, S\'ark\"ozy and Szemer\'edi proved that the $2$-color Ramsey
number $R(\mathcal{C}^k_n,\mathcal{C}^k_n)$ of a $k$-uniform loose cycle
$\mathcal{C}^k_n$ is asymptotically $\frac{1}{2}(2k-1)n,$ generating the same
result for $k=3$ due to Haxell et al. Concerning their results, it is
conjectured that for every $n\geq m\geq 3$ and $k\geq 3,$
$$R(\mathcal{C}^k_n,\mathcal{C}^k_m)=(k-1)n+\lfloor\frac{m-1}{2}\rfloor.$$ In
$2014$, the case $k=3$ is proved by the authors. Recently, the authors showed
that this conjecture is true for $n=m\geq 2$ and $k\geq 8$. In this paper, we
show that the conjecture holds for $k=4$ when $n>m$ or $n=m$ is odd. When $n=m$
is even, we show that $R(\mathcal{C}^4_n,\mathcal{C}^4_n)$ is between two
values with difference one.


title:
Coverage gain and Device-to-Device user Density: Stochastic Geometry
  Modeling and Analysis

abstract:
  Device-to-device (D2D) communication has huge potential for capacity and
coverage enhancements for next generation cellular networks. The number of
potential nodes for D2D communication is an important parameter that directly
impacts the system capacity. In this paper, we derive analytic expression for
average coverage probability of cellular user and corresponding number of
potential D2D users. In this context, mature framework of stochastic geometry
and Poisson point process has been used. The retention probability has been
incorporated in Laplace functional to capture reduced path-loss and shortest
distance criterion based D2D pairing. The numerical results show a close match
between analytic expression and simulation setup.


title: Understanding the Sparse Vector Technique for Differential Privacy

abstract:
  The Sparse Vector Technique (SVT) is a fundamental technique for satisfying
differential privacy and has the unique quality that one can output some query
answers without apparently paying any privacy cost. SVT has been used in both
the interactive setting, where one tries to answer a sequence of queries that
are not known ahead of the time, and in the non-interactive setting, where all
queries are known. Because of the potential savings on privacy budget, many
variants for SVT have been proposed and employed in privacy-preserving data
mining and publishing. However, most variants of SVT are actually not private.
In this paper, we analyze these errors and identify the misunderstandings that
likely contribute to them. We also propose a new version of SVT that provides
better utility, and introduce an effective technique to improve the performance
of SVT. These enhancements can be applied to improve utility in the interactive
setting. Through both analytical and experimental comparisons, we show that, in
the non-interactive setting (but not the interactive setting), the SVT
technique is unnecessary, as it can be replaced by the Exponential Mechanism
(EM) with better accuracy.


title: High-Dimensional Metrics in R

abstract:
  The package High-dimensional Metrics (\Rpackage{hdm}) is an evolving
collection of statistical methods for estimation and quantification of
uncertainty in high-dimensional approximately sparse models. It focuses on
providing confidence intervals and significance testing for (possibly many)
low-dimensional subcomponents of the high-dimensional parameter vector.
Efficient estimators and uniformly valid confidence intervals for regression
coefficients on target variables (e.g., treatment or policy variable) in a
high-dimensional approximately sparse regression model, for average treatment
effect (ATE) and average treatment effect for the treated (ATET), as well for
extensions of these parameters to the endogenous setting are provided. Theory
grounded, data-driven methods for selecting the penalization parameter in Lasso
regressions under heteroscedastic and non-Gaussian errors are implemented.
Moreover, joint/ simultaneous confidence intervals for regression coefficients
of a high-dimensional sparse regression are implemented, including a joint
significance test for Lasso regression. Data sets which have been used in the
literature and might be useful for classroom demonstration and for testing new
estimators are included. \R and the package \Rpackage{hdm} are open-source
software projects and can be freely downloaded from CRAN:
\texttt{http://cran.r-project.org}.


title: Optimization of STIRAP-based state transfer under dissipation

abstract:
  Using a perturbative treatment, we quantify the influence of non-adiabatic
leakage and system dissipation on the transfer fidelity of a stimulated Raman
adiabatic passage (STIRAP) process. We find that, optimizing transfer time
rather than coupling profiles, leads to a significant improvement of the
transfer fidelity. The upper bound of the fidelity has been found as a simple
analytical function of system cooperativities. We also provide a systematic
approach to reach this upper bound efficiently.


title:
Measurement of total and differential $W^+W^-$ production cross sections
  in proton-proton collisions at $\sqrt{s}=$ 8 TeV with the ATLAS detector and
  limits on anomalous triple-gauge-boson couplings

abstract:
  The production of $W$ boson pairs in proton-proton collisions at $\sqrt{s}=$
8 TeV is studied using data corresponding to 20.3 fb$^{-1}$ of integrated
luminosity collected by the ATLAS detector during 2012 at the CERN Large Hadron
Collider. The $W$ bosons are reconstructed using their leptonic decays into
electrons or muons and neutrinos. Events with reconstructed jets are not
included in the candidate event sample. A total of 6636 $WW$ candidate events
are observed. Measurements are performed in fiducial regions closely
approximating the detector acceptance. The integrated measurement is corrected
for all acceptance effects and for the $W$ branching fractions to leptons in
order to obtain the total $WW$ production cross section, which is found to be
71.1$\pm1.1$(stat)$^{+5.7}_{-5.0}$(syst)$\pm1.4$ pb. This agrees with the
next-to-next-to-leading-order Standard Model prediction of
63.2$^{+1.6}_{-1.4}$(scale)$\pm1.2$(PDF) pb. Fiducial differential cross
sections are measured as a function of each of six kinematic variables. The
distribution of the transverse momentum of the leading lepton is used to set
limits on anomalous triple-gauge-boson couplings.


title: NIHAO VI. The hidden discs of simulated galaxies

abstract:
  Detailed studies of galaxy formation require clear definitions of the
structural components of galaxies. Precisely defined components also enable
better comparisons between observations and simulations. We use a subsample of
eighteen cosmological zoom-in simulations from the NIHAO project to derive a
robust method for defining stellar kinematic discs in galaxies. Our method uses
Gaussian Mixture Models in a 3D space of dynamical variables. The NIHAO
galaxies have the right stellar mass for their halo mass, and their angular
momenta and S\'ersic indices match observations. While the photometric
disc-to-total ratios are close to 1 for all the simulated galaxies, the
kinematic ratios are around ~0.5. Thus, exponential structure does not imply a
cold kinematic disc. Above log(M*)~9.5, the decomposition leads to thin discs
and spheroids that have clearly different properties, in terms of angular
momentum, rotational support, ellipticity, [Fe/H] and [O/Fe]. At log(M*)<9.5,
the decomposition selects discs and spheroids with less distinct properties. At
these low masses, both the discs and spheroids have exponential profiles with
high minor-to-major axes ratios, i.e. thickened discs.


title:
Separation of elastic and inelastic processes in the relaxation time
  approximation for collision integral

abstract:
  We introduce a generalised relaxation-time-approximation form of the
collision term in the Boltzmann kinetic equation that allows for using
different relaxation times for elastic and inelastic collisions. The efficacy
of the proposed framework is demonstrated with the numerical calculations that
describe systems with different relations between the two relaxation times and
the evolution time of the system.


title: Syntomic cohomology and $p$-adic motivic cohomology

abstract:
  We prove a mixed characteristic analog of the Beilinson-Lichtenbaum
Conjecture for p-adic motivic cohomology. It gives a description, in the stable
range, of p-adic motivic cohomology (defined using algebraic cycles) in terms
of differential forms. This generalizes a result of Geisser from small Tate
twists to all twists and uses as a critical new ingredient the comparison
theorem between syntomic complexes and p-adic nearby cycles proved recently in
Colmez-Niziol.


title: Q-Fano threefolds of index $7$

abstract:
  We show that, for a $\mathbb Q$-Fano threefold $X$ of Fano index 7, the
inequality $\dim |-K_X| \ge 15$ implies that $X$ is isomorphic to one of the
following varieties $\mathbb P (1^2,2,3)$, $X_6 \subset \mathbb P (1,2^2,3,5)$
or $X_6 \subset \mathbb P (1,2,3^2,4)$.


title: Pulsar emission in the very-high-energy regime

abstract:
  The vast majority of the pulsars detected by the Fermi Large Area Telescope
(LAT) display spectra with exponential cutoffs falling in a narrow range around
a few GeV. Early spectral modelling predicted spectral cutoff energies of up to
100 GeV. More modern studies estimated spectral cutoff energies in the 1-20 GeV
range. It was therefore not expected that pulsars would be visible in the
very-high-energy (VHE; >100 GeV) regime. The VERITAS detection (confirmed by
MAGIC) of pulsed emission from the Crab pulsar up to 400 GeV (and now possibly
up to 1 TeV) therefore raised important questions about our understanding of
the electrodynamics and local environment of pulsars. H.E.S.S. has now detected
pulsed emission from the Vela pulsar in the 20-120 GeV range, making this the
second pulsar detected by a ground-based Cherenkov telescope. We will review
the latest developments in VHE pulsar science, including an overview of recent
observations and refinements to radiation models and magnetic field structures.
This will assist us in interpreting the VHE emission detected from the Crab and
Vela pulsars, and predicting the level of VHE emission expected from other
pulsars, which will be very important for the upcoming CTA.


title:
Technique Report: Near-Optimal Routing Protection for SDN Networks Using
  Distributed Markov Approximation

abstract:
  Software Defined Networking (SDN) brings numbers of advantages along with
many challenges. One particular concern is on the control-plane resilience,
while the existing protection approaches proposed for SDN networks mainly focus
on data-plane. In order to achieve the carrier-grade recovery from link
failures, we adopt the dedicated protection scheme towards finding optimal
protection routing for control-plane traffic. To this end, we study a weighted
cost minimization problem, in which the traffic load balancing and flow table
rule placement are jointly considered when selecting protection paths for
controller-switch sessions. Because this problem is known as NP-hard, we
propose a Markov approximation based combinatorial optimization approach for
routing protection in SDN control-plane, which produces near-optimal solution
in a distributed fashion. We then extend our solution to an on-line case that
can handle the single-link failure one at a time. The induced performance
fluctuation is also analyzed with theoretical derivation. Extensive
experimental results show that our proposed algorithm has fast convergence and
high efficiency in resource utilization.


title:
Subdiffusivity of a random walk among a Poisson system of moving traps
  on ${\mathbb Z}$

abstract:
  We consider a random walk among a Poisson system of moving traps on ${\mathbb
Z}$. In earlier work [DGRS12], the quenched and annealed survival probabilities
of this random walk have been investigated. Here we study the path of the
random walk conditioned on survival up to time $t$ in the annealed case and
show that it is subdiffusive. As a by-product, we obtain an upper bound on the
number of so-called thin points of a one-dimensional random walk, as well as a
bound on the total volume of the holes in the random walk's range.


title: Locally toroidal polytopes of rank 6 and sporadic groups

abstract:
  We augment the list of finite universal locally toroidal regular polytopes of
type {3,3,4,3,3} due to P.McMullen and E.Schulte, adding as well as removing
entries. This disproves a related long-standing conjecture. Our new universal
polytope is related to a well-known Y-shaped presentation for the sporadic
simple group $Fi_{22}$, and admits $S_4\times O_8^+(2){:}S_3$ as the
automorphism group. We also discuss further extensions of its quotients in the
context of Y-shaped presentations. As well, we note that two known examples of
finite universal polytopes of type {3,3,4,3,3} are related to Y-shaped
presentations of orthogonal groups over GF(2). Mixing construction is used in a
number of places to describe covers and 2-covers.


title: Projective structures and $\rho$-connections

abstract:
  We extend T. Y. Thomas's approach to the projective structures, over the
complex analytic category, by involving the $\rho$-connections. This way, a
better control of the projective flatness is obtained and, consequently, we
have, for example, the following application: if the twistor space of a
quaternionic manifold $P$ is endowed with a complex projective structure then
$P$ can be locally identified, through quaternionic diffeomorphisms, with the
quaternionic projective space.


title:
Stationary Axisymmetric Configuration of the Resistive Thick Accretion
  Tori around a Schwarzschild Black Hole

abstract:
  We examine a thick accretion disc in the presence of external gravity and
intrinsic dipolar magnetic field due to a non-rotating central object. In this
paper, we generalize the Newtonian theory of stationary axisymmetric resistive
tori of Tripathy, Prasanna $\&$ Das (1990) by including the fully general
relativistic features. If we are to obtain the steady state configuration, we
have to take into account the finite resistivity for the magnetofluid in order
to avoid the piling up of the field lines anywhere in the accretion discs. The
efficient value of conductivity must be much smaller than the classical
conductivity to be astrophysically interesting. The accreting plasma in the
presence of an external dipole magnetic field gives rise to a current in the
azimuthal direction. The azimuthal current produced due to the motion of the
magnetofluid modifies the magnetic field structure inside the disc and
generates a poloidal magnetic field for the disc. The solutions we have found
show that the radial inflow, pressure and density distributions are strongly
modified by the electrical conductivity both in relativistic and Newtonian
regimes. However, the range of conductivity coefficient is different for both
regimes, as well as that of the angular momentum parameter and the radius of
the innermost stable circular orbit. Furthermore, it is shown that the
azimuthal velocity of the disc which is not dependent on conductivity is
sub-Keplerian in all radial distances for both regimes. Owing to the presence
of pressure gradient and magnetic forces. This work may also be important for
the general relativistic computational magnetohydrodynamics that suffers from
the lack of exact analytic solutions that are needed to test computer codes.


title:
Reducing the dosimetric impact of positional errors in field junctions
  for craniospinal irradiation using VMAT

abstract:
  Aim: To improve treatment plan robustness with respect to small shifts in
patient position during the VMAT treatment by ensuring a linear ramp-like dose
profile in treatment field overlap regions.
  Background: Craniospinal irradiation (CSI) is considered technically
challenging because the target size exceeds the maximal field size, which
necessitates using abutted or overlapping treatment fields. Volumetric
modulated arc therapy (VMAT) is increasingly being examined for CSI, as it
offers both better dose homogeneity and better dose conformance while also
offering a possibility to create field junctions which are more robust towards
small shifts in patient position during the treatment.
  Materials and Methods: A VMAT treatment plan with three isocenters was made
for a test case patient. Three groups of overlapping arc field pairs were used;
one for the cranial and two for the spinal part. In order to assure a ramp-like
dose profile in the field overlap region, the upper spinal part was optimised
first, with dose prescription explicitely enforcing a ramp-like dose profile.
The cranial and lower spinal part were done afterwards, taking into account the
dose contribution of the upper spinal fields.
  Results: Using simple geometrical reasoning, we demonstrated that hot- and
cold spots which arise from small displacement of one treatment field relative
to the other treatment field can be reduced by taking two precautions: (a)
widening the field overlap region, and (b) reducing the field gradient across
the overlap region. The function with the smallest maximal gradient is a linear
ramp. We present a treatment planning technique which yields the desired dose
profile of the two contributing fields, and minimises dosimetric dependence on
minor positional errors in patient set-up.


title:
Enhancement of the spin transfer torque efficiency in magnetic STM
  junctions

abstract:
  We introduce a method for a combined calculation of charge and vector spin
transport of elastically tunneling electrons in magnetic scanning tunneling
microscopy (STM). The method is based on the three-dimensional
Wentzel-Kramers-Brillouin (3D-WKB) approach combined with electronic structure
calculations using first principles density functional theory. As an
application, we analyze the STM contrast inversion of the charge current above
the Fe/W(110) surface depending on the bias voltage, tip-sample distance and
relative magnetization orientation between the sample and an iron tip. For the
spin transfer torque (STT) vector we find that its in-plane component is
generally larger than the out-of-plane component, and we identify a
longitudinal spin current component, which, however, does not contribute to the
torque. Our results suggest that the torque-current relationship in magnetic
STM junctions follows the power law rather than a linear function.
Consequently, we show that the ratio between the STT and the spin-polarized
charge current is not constant, and more importantly, it can be tuned by the
bias voltage, tip-sample distance and magnetization rotation. We find that the
STT efficiency can be enhanced by about a factor of seven by selecting a proper
bias voltage. Thus, we demonstrate the possible enhancement of the STT
efficiency in magnetic STM junctions, which can be exploited in technological
applications. We discuss our results in view of the indirect measurement of the
STT above the Fe/W(110) surface reported by Krause et al. in Phys. Rev. Lett.
107, 186601 (2011).


title: Higher order symmetries for linear and nonlinear Schroedinger equations

abstract:
  We study arbitrary order symmetry operators for the linear Schr\"odinger
equations with arbitrary number of spatial variables. We deduce determining
equations for coefficient functions of such operators and consider in detail
some cases when these equations can be explicitly solved. In addition, the
complete group classification of the nonlinear Schr\"odinger equation is
presented.


title: Classifier ensemble creation via false labelling

abstract:
  In this paper, a novel approach to classifier ensemble creation is presented.
While other ensemble creation techniques are based on careful selection of
existing classifiers or preprocessing of the data, the presented approach
automatically creates an optimal labelling for a number of classifiers, which
are then assigned to the original data instances and fed to classifiers. The
approach has been evaluated on high-dimensional biomedical datasets. The
results show that the approach outperformed individual approaches in all cases.


title:
Topological phase transition induced extreme magnetoresistance in
  TaSb$_{2}$

abstract:
  We report extremely large positive magnetoresistance of 1.72 million percent
in single crystal TaSb$_{2}$ at moderate conditions of 1.5 K and 15 T. The
quadratic growth of magnetoresistance (MR $\propto\,B^{1.96}$) is not
saturating up to 15 T, a manifestation of nearly perfect compensation with
$<0.1\%$ mismatch between electron and hole pockets in this semimetal. The
compensation mechanism is confirmed by temperature-dependent MR, Hall and
thermoelectric coefficients of Nernst and Seebeck, revealing two pronounced
Fermi surface reconstruction processes without spontaneous symmetry breaking,
\textit{i.e.} Lifshitz transitions, at around 20 K and 60 K, respectively.
Using quantum oscillations of magnetoresistance and magnetic susceptibility,
supported by density-functional theory calculations, we determined that the
main hole Fermi surface of TaSb$_{2}$ forms a unique shoulder structure along
the $F-L$ line. The flat band top of this shoulder pocket is just a few meV
above the Fermi level, leading to the observed topological phase transition at
20 K when the shoulder pocket disappears. Further increase in temperature
pushes the Fermi level to the band top of the main hole pocket, induced the
second Lifshitz transition at 60 K when hole pocket vanishes completely.


title:
Extracting the resonance parameters from experimental data on scattering
  of charged particles

abstract:
  A new parametrization of the multi-channel S-matrix is used to fit scattering
data and then to locate the resonances as its poles. The S-matrix is written in
terms of the corresponding "in" and "out" Jost matrices which are expanded in
the Taylor series of the collision energy E around an appropriately chosen
energy E0. In order to do this, the Jost matrices are written in a
semi-analytic form where all the factors (involving the channel momenta and
Sommerfeld parameters) responsible for their "bad behaviour" (i.e. responsible
for the multi-valuedness of the Jost matrices and for branching of the Riemann
surface of the energy) are given explicitly. The remaining unknown factors in
the Jost matrices are analytic and single-valued functions of the variable E
and are defined on a simple energy plane. The expansion is done for these
analytic functions and the expansion coefficients are used as the fitting
parameters. The method is tested on a two-channel model, using a set of
artificially generated data points with typical error bars and a typical random
noise in the positions of the points.


title: Development and characterization of single gap glass RPC

abstract:
  India-based Neutrino Observatory (INO) facility is going to have a 50 kton
magnetized Iron CALorimeter (ICAL) detector for precision measurements of
neutrino oscillations using atmospheric neutrinos. The proposed ICAL detector
will be a stack of magnetized iron plates (acting as target material)
interleaved with glass Resistive Plate Chambers (RPCs) as the active detector
elements. An RPC is a gaseous detector made up of two parallel electrode plates
having high bulk resistivity like that of float glass and bakelite. For the
ICAL detector, glass is preferred over bakelite as it does not need any kind of
surface treatment to achieve better surface uniformity and also the cost of
associated electronics is reduced. Under the detector R&D efforts for the
proposed glass RPC detector, a few glass RPCs of 1m X 1m dimension are
fabricated procuring glass of ~ 2 mm thickness from one of the Indian glass
manufacturers (Asahi). In the present paper, we report the characterization of
RPC based on leakage current study, muon detection efficiency and noise rate
studies with varying gas compositions.


title: The quadratic covariation for a weighted fractional Brownian motion

abstract:
  Let $B^{a,b}$ be a weighted fractional Brownian motion with indices $a,b$
satisfying $a>-1,-1<b<0,|b|<1+a$. In this paper, motivated by the asymptotic
property $$ E[(B^{a,b}_{s+\varepsilon}-B^{a,b}_s)^2]
=O(\varepsilon^{1+b})\not\sim
\varepsilon^{1+a+b}=E[(B^{a,b}_{\varepsilon})^2]\qquad (\varepsilon\to 0) $$
for all $s>0$, we consider the generalized quadratic covariation
$\bigl[f(B^{a,b}),B^{a,b}\bigr]^{(a,b)}$ defined by $$
\bigl[f(B^{a,b}),B^{a,b}\bigr]^{(a,b)}_t=\lim_{\varepsilon\downarrow
0}\frac{1+a+b}{\varepsilon^{1+b}}\int_\varepsilon^{t+\varepsilon}
\left\{f(B^{a,b}_{s+\varepsilon})
-f(B^{a,b}_s)\right\}(B^{a,b}_{s+\varepsilon}-B^{a,b}_s)s^{b}ds, $$ provided
the limit exists uniformly in probability. We construct a Banach space
${\mathscr H}$ of measurable functions such that the generalized quadratic
covariation exists in $L^2(\Omega)$ and the generalized Bouleau-Yor identity $$
[f(B^{a,b}),B^{a,b}]^{(a,b)}_t=-\frac1{(1+b){\mathbb B}(a+1,b+1)} \int_{\mathbb
R}f(x){\mathscr L}^{a,b}(dx,t) $$ holds for all $f\in {\mathscr H}$, where
${\mathscr L}^{a,b}(x,t)=\int_0^t\delta(B^{a,b}_s-x)ds^{1+a+b}$ is the weighted
local time of $B^{a,b}$ and ${\mathbb B}(\cdot,\cdot)$ is the Beta function.


title: An independent discovery of two hot Jupiters from the K2 mission

abstract:
  We report the discovery of two hot Jupiters using photometry from Campaigns 4
and 5 of the two-wheeled Kepler (K2) mission. K2-30b has a mass of $ 0.65 \pm
0.14 M_J$, a radius of $1.070 \pm 0.018 R_J$ and transits its G dwarf ($T_{eff}
= 5675 \pm 50$ K), slightly metal rich ([Fe/H]$=+0.06\pm0.04$ dex) host star in
a 4.1 days circular orbit. K2-34b has a mass of $ 1.63 \pm 0.12 M_J$, a radius
of $1.38 \pm 0.014 R_J$ and has an orbital period of 3.0 days in which it
orbits a late F dwarf ($T_{eff} = 6149 \pm 55$ K) solar metallicity star. Both
planets were validated probabilistically and confirmed via precision radial
velocity (RV) measurements. They have physical and orbital properties similar
to the ones of the already uncovered population of hot Jupiters and are
well-suited candidates for further orbital and atmospheric characterization via
detailed follow-up observations. Given that the discovery of both systems was
recently reported by other groups we take the opportunity of refining the
planetary parameters by including the RVs obtained by these independent studies
in our global analysis.


title:
A Linked Data Scalability Challenge: Concept Reuse Leads to Semantic
  Decay

abstract:
  The increasing amount of available Linked Data resources is laying the
foundations for more advanced Semantic Web applications. One of their main
limitations, however, remains the general low level of data quality. In this
paper we focus on a measure of quality which is negatively affected by the
increase of the available resources. We propose a measure of semantic richness
of Linked Data concepts and we demonstrate our hypothesis that the more a
concept is reused, the less semantically rich it becomes. This is a significant
scalability issue, as one of the core aspects of Linked Data is the propagation
of semantic information on the Web by reusing common terms. We prove our
hypothesis with respect to our measure of semantic richness and we validate our
model empirically. Finally, we suggest possible future directions to address
this scalability problem.


title: Nuclear fusion induced by X-rays in a crystal

abstract:
  The nuclei that constitute a crystalline lattice, oscillate relative to each
other with a very low energy that is not sufficient to penetrate through the
Coulomb barriers separating them. An additional energy, which is needed to
tunnel through the barrier and fuse, can be supplied by external
electromagnetic waves (X-rays or the synchrotron radiation). Exposing to the
X-rays the solid compound LiD (lithium-deuteride) for the duration of 111
hours, we have detected 88 events of the nuclear fusion d+Li6 ---> Be8*. Our
theoretical estimate agrees with what we observed. One of possible applications
of the phenomenon we found, could be the measurements of the rates of various
nuclear reactions (not necessarily fusion) at extremely low energies
inaccessible in accelerator experiments.


title: Elliptic genera from multi-centers

abstract:
  I show how elliptic genera for various Calabi-Yau threefolds may be
understood from supergravity localization using the quantization of the phase
space of certain multi-center configurations. I present a simple procedure that
allows for the enumeration of all multi-center configurations contributing to
the polar sector of the elliptic genera\textemdash explicitly verifying this in
the cases of the quintic in $\mathbb{P}^4$, the sextic in
$\mathbb{WP}_{(2,1,1,1,1)}$, the octic in $\mathbb{WP}_{(4,1,1,1,1)}$ and the
dectic in $\mathbb{WP}_{(5,2,1,1,1)}$. With an input of the corresponding
`single-center' indices (Donaldson-Thomas invariants), the polar terms have
been known to determine the elliptic genera completely. I argue that this
multi-center approach to the low-lying spectrum of the elliptic genera is a
stepping stone towards an understanding of the exact microscopic states that
contribute to supersymmetric single center black hole entropy in
$\mathcal{N}=2$ supergravity.


title:
Exploiting spatiotemporal degrees of freedom for far field subwavelength
  focusing using time reversal in fractals

abstract:
  Materials which possess a high local density of states varying at a
subwavelength scale theoretically permit to focus waves onto focal spots much
smaller than the free space wavelength. To do so metamaterials -manmade
composite media exhibiting properties not available in nature- are usually
considered. However this approach is limited to narrow bandwidths due to their
resonant nature. Here, we prove that it is possible to use a fractal resonator
alongside time reversal to focus microwaves onto $\lambda/15$ subwavelength
focal spots from the far field, on extremely wide bandwidths. We first
numerically prove that this approach can be realized using a multiple channel
time reversal mirror, that utilizes all the degrees of freedom offered by the
fractal resonator. Then we experimentally demonstrate that this approach can be
drastically simplified by coupling the fractal resonator to a complex medium,
here a cavity, that efficiently converts its spatial degrees of freedom into
temporal ones. This allows to achieve deep subwavelength focusing of microwaves
using a single channel time reversal. Our method can be generalized to other
systems coupling complex media and fractal resonators.


title:
An exploration of normalish subgroups of R. Thompson's groups $F$ and
  $T$

abstract:
  In this short note, we show that R. Thompson's group $F$ admits a normalish
amenable subgroup, and that the standard copy of $F$ in R. Thompson's group $T$
is normalish in $T$. We further conjecture that if $F$ is non-amenable, then
$T$ does not admit a normalish amenable subgroup, and therefore that the
reduced $C^*$ algebra of $T$ is in fact simple in that case.


title:
Branching diffusion representation of semilinear PDEs and Monte Carlo
  approximation

abstract:
  We provide a representation result of parabolic semi-linear PD-Es, with
polynomial nonlinearity, by branching diffusion processes. We extend the
classical representation for KPP equations, introduced by Skorokhod (1964),
Watanabe (1965) and McKean (1975), by allowing for polynomial nonlinearity in
the pair $(u, Du)$, where $u$ is the solution of the PDE with space gradient
$Du$. Similar to the previous literature, our result requires a non-explosion
condition which restrict to "small maturity" or "small nonlinearity" of the
PDE. Our main ingredient is the automatic differentiation technique as in Henry
Labordere, Tan and Touzi (2015), based on the Malliavin integration by parts,
which allows to account for the nonlinearities in the gradient. As a
consequence, the particles of our branching diffusion are marked by the nature
of the nonlinearity. This new representation has very important numerical
implications as it is suitable for Monte Carlo simulation. Indeed, this
provides the first numerical method for high dimensional nonlinear PDEs with
error estimate induced by the dimension-free Central limit theorem. The
complexity is also easily seen to be of the order of the squared dimension. The
final section of this paper illustrates the efficiency of the algorithm by some
high dimensional numerical experiments.


title:
An Integrated Model for the Production of X-Ray Time Lags and Quiescent
  Spectra from Homogeneous and Inhomogeneous Black Hole Accretion Coronae

abstract:
  Many accreting black holes manifest time lags during outbursts, in which the
hard Fourier component typically lags behind the soft component. Despite
decades of observations of this phenomenon, the underlying physical explanation
for the time lags has remained elusive, although there are suggestions that
Compton reverberation plays an important role. However, the lack of analytical
solutions has hindered the interpretation of the available data. In this paper,
we investigate the generation of X-ray time lags in Compton scattering coronae
using a new mathematical approach based on analysis of the Fourier-transformed
transport equation. By solving this equation, we obtain the Fourier transform
of the radiation Green's function, which allows us to calculate the exact
dependence of the time lags on the Fourier frequency, for both homogeneous and
inhomogeneous coronal clouds. We use the new formalism to explore a variety of
injection scenarios, including both monochromatic and broadband
(bremsstrahlung) seed photon injection. We show that our model can successfully
reproduce both the observed time lags and the time-averaged (quiescent) X-ray
spectra for Cyg~X-1 and GX~339-04, using a single set of coronal parameters for
each source. The time lags are the result of impulsive bremsstrahlung injection
occurring near the outer edge of the corona, while the time-averaged spectra
are the result of continual distributed injection of soft photons throughout
the cloud.


title:
Low-Rank Matrix Completion for Topological Interference Management by
  Riemannian Pursuit

abstract:
  In this paper, we present a flexible low-rank matrix completion (LRMC)
approach for topological interference management (TIM) in the partially
connected K-user interference channel. No channel state information (CSI) is
required at the transmitters except the network topology information. The
previous attempt on the TIM problem is mainly based on its equivalence to the
index coding problem, but so far only a few index coding problems have been
solved. In contrast, in this paper, we present an algorithmic approach to
investigate the achievable degrees-of-freedom (DoFs) by recasting the TIM
problem as an LRMC problem. Unfortunately, the resulting LRMC problem is known
to be NP-hard, and the main contribution of this paper is to propose a
Riemannian pursuit (RP) framework to detect the rank of the matrix to be
recovered by iteratively increasing the rank. This algorithm solves a sequence
of fixed-rank matrix completion problems. To address the convergence issues in
the existing fixed-rank optimization methods, the quotient manifold geometry of
the search space of fixed-rank matrices is exploited via Riemannian
optimization. By further exploiting the structure of the low-rank matrix
varieties, i.e., the closure of the set of fixed- rank matrices, we develop an
efficient rank increasing strategy to find good initial points in the procedure
of rank pursuit. Simulation results demonstrate that the proposed RP algorithm
achieves a faster convergence rate and higher achievable DoFs for the TIM
problem compared with the state-of-the-art methods.


title: Electron correlations and silicon nanocluster energetics

abstract:
  The first-principle prediction of nanocluster stable structure is often
hampered by the existence of many isomer configurations with energies close to
the ground state. This fact attaches additional importance to many-electron
effects going beyond density functional theory (DFT), because their
contributions may change a subtle energy order of competitive structures. To
analyze this problem, we consider, as an example, the energetics of silicon
nanoclusters passivated by hydrogen Si$_{10}$H$_{2n}$ with $0\le n\le 11$, the
structure of which varies with passivation from compact to loose-packed,
similar to branching polymers. Our calculations performed by the DFT, hybrid
functionals and Hartree-Fock (H-F) methods, as well as by the GW approximation
(GWA), confirm a considerable sensitivity of structure prediction and isomer
energy ordering to many-electron effects and show some results which may be
obtained with the methods less computationally demanding than the GWA.


title: The local indistinguishability of multipartite product states

abstract:
  In this paper, we mainly study the local indistinguishability of multipartite
product states. Firstly, we follow the method of Z.-C. Zhang \emph{et al}[Phys.
Rev. A 93, 012314(2016)] to give another more concise set of $2n-1$ orthogonal
product states in $\mathbb{C}^m\otimes\mathbb{C}^n(4\leq m\leq n)$ which can
not be distinguished by local operations and classical communication(LOCC).
Then we use the 3 dimension cubes to present some product states which give us
an intuitive view how to construct locally indistinguishable product states in
tripartite quantum system. At last, we give an explicit construction of locally
indistinguishable orthogonal product states for general multipartite system.


title: Controlling the Characteristics of Nanomechanical Resonators

abstract:
  The dynamics of nanomechanical resonators driven by both low- and
high-frequency signals is studied. Considering, as an example, resonators made
of a doubly-clamped beam with magnetomotive driving, it is shown that
three-frequency resonances arise due to the interaction of the above
frequencies. Properties and characteristics of these resonances are determined
analytically for linear and nonlinear modes of the resonator excitation. It is
shown that in opposite to the conventional two-frequency resonance, the central
frequency of these resonances, their linear dynamic range, and the critical
value for the bistability onset are easily controlled by changing the frequency
and the amplitude of the low-frequency driving current. The obtained results
can be used when developing NMRs for sensors, filters, memory elements, and
other applications.


title: New Algorithms for Heavy Hitters in Data Streams

abstract:
  An old and fundamental problem in databases and data streams is that of
finding the heavy hitters, also known as the top-$k$, most popular items,
frequent items, elephants, or iceberg queries. There are several variants of
this problem, which quantify what it means for an item to be frequent,
including what are known as the $\ell_1$-heavy hitters and $\ell_2$-heavy
hitters. There are a number of algorithmic solutions for these problems,
starting with the work of Misra and Gries, as well as the CountMin and
CountSketch data structures, among others.
  In this survey paper, accompanying an ICDT invited talk, we cover several
recent results developed in this area, which improve upon the classical
solutions to these problems. In particular, with coauthors we develop new
algorithms for finding $\ell_1$-heavy hitters and $\ell_2$-heavy hitters, with
significantly less memory required than what was known, and which are optimal
in a number of parameter regimes.


title: Freiman homomorphisms on sparse random sets

abstract:
  A result of Fiz Pontiveros shows that if $A$ is a random subset of
$\mathbb{Z}_N$ where each element is chosen independently with probability
$N^{-1/2+o(1)}$, then with high probability every Freiman homomorphism defined
on $A$ can be extended to a Freiman homomorphism on the whole of
$\mathbb{Z}_N$. In this paper we improve the bound to $CN^{-2/3}(\log
N)^{1/3}$, which is best possible up to the constant factor.


title:
A Beurling-Blecher-Labuschagne Theorem for noncommutative Hardy spaces
  associated with semifinite von Neumann algebras

abstract:
  In 2008, Blecher and Labuschagne extended Beurling's classical theorem to
$H^\infty$-invariant subspaces of $L^p(\mathcal{M},\tau)$ for a finite von
Neumann algebra $\mathcal{M}$ with a finite, faithful, normal tracial state
$\tau$ when $1\le p\le \infty$. In this paper, using Arveson's non-commutative
Hardy space $H^\infty$ in relation to a von Neumann algebra $\mathcal{M}$ with
a semifinite, faithful, normal tracial weight $\tau$, we prove a
Beurling-Blecher-Labuschagne theorem for $H^\infty$-invariant spaces of
$L^p(\mathcal{M},\tau)$ when $0<p\leq\infty$. The proof of the main result
relies on proofs of density theorems for $L^p(\mathcal{M},\tau)$ and semifinite
versions of several other known theorems from the finite case. Using the main
result, we are able to completely characterize all $H^\infty$-invariant
subspaces of $L^p(\mathcal M\rtimes_\alpha \mathbb Z,\tau)$, where $\mathcal
M\rtimes_\alpha \mathbb Z $ is a crossed product of a semifinite von Neumann
algebra $\mathcal{M}$ by the integer group $\mathbb Z$ and $H^\infty$ is a
non-selfadjoint crossed product of $\mathcal{M}$ by $\mathbb Z^+$. As an
example, we characterize all $H^\infty$-invariant subspaces of the Schatten
$p$-class $S^p(\mathcal{H})$, where $H^\infty$ is the lower triangular
subalgebra of $B(\mathcal H)$, for each $0<p\leq\infty$.


title: Some Results on Superpatterns for Preferential Arrangements

abstract:
  A {\it superpattern} is a string of characters of length $n$ that contains as
a subsequence, and in a sense that depends on the context, all the smaller
strings of length $k$ in a certain class. We prove structural and probabilistic
results on superpatterns for {\em preferential arrangements}, including (i) a
theorem that demonstrates that a string is a superpattern for all preferential
arrangements if and only if it is a superpattern for all permutations; and (ii)
a result that is reminiscent of a still unresolved conjecture of Alon on the
smallest permutation on $[n]$ that contains all $k$-permutations with high
probability.


title:
On the $p$-Laplacian with Robin boundary conditions and boundary trace
  theorems

abstract:
  Let $\Omega\subset\mathbb{R}^\nu$, $\nu\ge 2$, be a $C^{1,1}$ domain whose
boundary $\partial\Omega$ is either compact or behaves suitably at infinity.
For $p\in(1,\infty)$ and $\alpha>0$, define \[
\Lambda(\Omega,p,\alpha):=\inf_{\substack{u\in W^{1,p}(\Omega)\\ u\not\equiv
0}}\dfrac{\displaystyle \int_\Omega |\nabla u|^p \mathrm{d} x -
\alpha\displaystyle\int_{\partial\Omega}
|u|^p\mathrm{d}\sigma}{\displaystyle\int_\Omega |u|^p\mathrm{d} x}, \] where
$\mathrm{d}\sigma$ is the surface measure on $\partial\Omega$. We show the
asymptotics \[ \Lambda(\Omega,p,\alpha)=-(p-1)\alpha^{\frac{p}{p-1}} -
(\nu-1)H_\mathrm{max}\, \alpha + o(\alpha), \quad \alpha\to+\infty, \] where
$H_\mathrm{max}$ is the maximum mean curvature of $\partial\Omega$. The
asymptotic behavior of the associated minimizers is discussed as well. The
estimate is then applied to the study of the best constant in a boundary trace
theorem for expanding domains, to the norm estimate for extension operators and
to related isoperimetric inequalities.


title:
Tree-level equivalence between a Lorentz-violating extension of QED and
  its dual model in electron-electron scattering

abstract:
  S-matrix amplitudes for the electron-electron scattering are calculated in
order to verify the quantum equivalence of dual models. We used an extended
Quantum Electrodynamics with CPT-even Lorentz-violating kinetic and mass terms,
which was used in a process of gauge embedding, known as Noether dualizationn
method (NDM), in order to generate its gauge-invariant dual model. The physical
equivalence was established at tree-level and the cross section was calculated
to second order in the Lorentz-violating parameter.


title:
Grading of Mammalian Cumulus Oocyte Complexes using Machine Learning for
  in Vitro Embryo Culture

abstract:
  Visual observation of Cumulus Oocyte Complexes provides only limited
information about its functional competence, whereas the molecular evaluations
methods are cumbersome or costly. Image analysis of mammalian oocytes can
provide attractive alternative to address this challenge. However, it is
complex, given the huge number of oocytes under inspection and the subjective
nature of the features inspected for identification. Supervised machine
learning methods like random forest with annotations from expert biologists can
make the analysis task standardized and reduces inter-subject variability. We
present a semi-automatic framework for predicting the class an oocyte belongs
to, based on multi-object parametric segmentation on the acquired microscopic
image followed by a feature based classification using random forests.


title: New Algorithms for Maximum Disjoint Paths Based on Tree-Likeness

abstract:
  We study the classical NP-hard problems of finding maximum-size subsets from
given sets of $k$ terminal pairs that can be routed via edge-disjoint paths
(MaxEDP) or node-disjoint paths (MaxNDP) in a given graph. The approximability
of MaxEDP/NDP is currently not well understood; the best known lower bound is
$\Omega(\log^{1/2-\epsilon}{n})$, assuming
NP$~\not\subseteq~$ZPTIME$(n^{\mathrm{poly}\log n})$. This constitutes a
significant gap to the best known approximation upper bound of $O(\sqrt{n})$
due to Chekuri et al. (2006) and closing this gap is currently one of the big
open problems in approximation algorithms. In their seminal paper, Raghavan and
Thompson (Combinatorica, 1987) introduce the technique of randomized rounding
for LPs; their technique gives an $O(1)$-approximation when edges (or nodes)
may be used by $O(\frac{\log n}{\log\log n})$ paths.
  In this paper, we strengthen the above fundamental results. We provide new
bounds formulated in terms of the feedback vertex set number $r$ of a graph,
which measures its vertex deletion distance to a forest. In particular, we
obtain the following.
  * For MaxEDP, we give an $O(\sqrt{r}\cdot \log^{1.5}{kr})$-approximation
algorithm. As $r\leq n$, up to logarithmic factors, our result strengthens the
best known ratio $O(\sqrt{n})$ due to Chekuri et al.
  * Further, we show how to route $\Omega(\mathrm{OPT})$ pairs with congestion
$O(\frac{\log{kr}}{\log\log{kr}})$, strengthening the bound obtained by the
classic approach of Raghavan and Thompson.
  * For MaxNDP, we give an algorithm that gives the optimal answer in time
$(k+r)^{O(r)}\cdot n$. If $r$ is at most triple-exponential in $k$, this
improves the best known algorithm for MaxNDP with parameter $k$, by
Kawarabayashi and Wollan (STOC 2010).
  We complement these positive results by proving that MaxEDP is NP-hard even
for $r=1$, and MaxNDP is W$[1]$-hard for parameter $r$.


title:
Interstellar neutral helium in the heliosphere from IBEX observations.
  IV. Flow vector, Mach number, and abundance of the Warm Breeze

abstract:
  With the velocity vector and temperature of the pristine interstellar neutral
(ISN) He recently obtained with high precision from a coordinated analysis
summarized by McComas et al.2015b, we analyzed the IBEX observations of neutral
He left out from this analysis. These observations were collected during the
ISN observation seasons 2010---2014 and cover the region in the Earth's orbit
where the Warm Breeze persists. We used the same simulation model and a very
similar parameter fitting method to that used for the analysis of ISN He. We
approximated the parent population of the Warm Breeze in front of the
heliosphere with a homogeneous Maxwell-Boltzmann distribution function and
found a temperature of $\sim 9\,500$ K, an inflow speed of 11.3 km s$^{-1}$,
and an inflow longitude and latitude in the J2000 ecliptic coordinates
$251.6^\circ$, $12.0^\circ$. The abundance of the Warm Breeze relative to the
interstellar neutral He is 5.7\% and the Mach number is 1.97. The newly found
inflow direction of the Warm Breeze, the inflow directions of ISN H and ISN He,
and the direction to the center of IBEX Ribbon are almost perfectly co-planar,
and this plane coincides within relatively narrow statistical uncertainties
with the plane fitted only to the inflow directions of ISN He, ISN H, and the
Warm Breeze. This co-planarity lends support to the hypothesis that the Warm
Breeze is the secondary population of ISN He and that the center of the Ribbon
coincides with the direction of the local interstellar magnetic field. The
common plane for the direction of inflow of ISN gas, ISN H, the Warm Breeze,
and the local interstellar magnetic field %includes the Sun and is given by the
normal direction: ecliptic longitude $349.7^\circ \pm 0.6^\circ$ and latitude
$35.7^\circ \pm 0.6^\circ$ in the J2000 coordinates, with the correlation
coefficient of 0.85.


title: The outer profile of dark matter halos: an analytical approach

abstract:
  A steepening feature in the outer density profiles of dark matter halos
indicating the splashback radius has drawn much attention recently. Possible
observational detections have even been made for galaxy clusters.
Theoretically, Adhikari et al. have estimated the location of the splashback
radius by computing the secondary infall trajectory of a dark matter shell
through a growing dark matter halo with an NFW profile. However, since they
imposed a shape of the halo profile rather than computing it consistently from
the trajectories of the dark matter shells, they could not provide the full
shape of the dark matter profile around the splashback radius. We improve on
this by extending the self-similar spherical collapse model of Fillmore \&
Goldreich to a $\Lambda$CDM universe. This allows us to compute the dark matter
halo profile and the trajectories simultaneously from the mass accretion
history. Our results on the splashback location agree qualitatively with
Adhikari et al. but with small quantitative differences at large mass accretion
rates. We present new fitting formulae for the splashback radius $R_{\rm sp}$
in various forms, including the ratios of $R_{\rm sp} / R_{\rm 200c}$ and
$R_{\rm sp} / R_{\rm 200m}$. Numerical simulations have made the puzzling
discovery that the splashback radius scales well with $R_{\rm 200m}$ but not
with $R_{\rm 200c}$. We trace the origin of this to be the correlated increase
of $\Omega_{\rm m}$ and the average halo mass accretion rate with an increasing
redshift.


title:
Uniqueness of constant scalar curvature K\"ahler metrics with cone
  singularities, I: Reductivity

abstract:
  The aim of this paper is to investigate uniqueness of conic constant scalar
curvature Kaehler (cscK) metrics, when the cone angle is less than $\pi$. We
introduce a new H\"older space called $\cC^{4,\a,\b}$ to study the regularities
of this fourth order elliptic equation, and prove that any $\cC^{2,\a,\b}$
conic cscK metric is indeed of class $\cC^{4,\a,\b}$. Finally, the reductivity
is established by a careful study of the conic Lichnerowicz operator.


title: Ergodic properties of matrix equilibrium states

abstract:
  Given a finite irreducible set of real $d \times d$ matrices $A_1,\ldots,A_M$
and a real parameter $s>0$, there exists a unique shift-invariant equilibrium
state associated to $(A_1,\ldots,A_M,s)$. In this article we characterise the
ergodic properties of such equilibrium states in terms of the algebraic
properties of the semigroup generated by the associated matrices. We completely
characterise when the equilibrium state has zero entropy, when it gives
distinct Lyapunov exponents to the natural cocycle generated by
$A_1,\ldots,A_M$, and when it is a Bernoulli measure. We also give a general
sufficient condition for the equilibrium state to be mixing, and give an
example where the equilibrium state is ergodic but not totally ergodic.
Connections with a class of measures investigated by S. Kusuoka are explored in
an appendix.


title:
Momentum-Resolved Electronic Structure of the High-$T_{c}$
  Superconductor Parent Compound BaBiO$_{3}$

abstract:
  We investigate the band structure of BaBiO$_{3}$, an insulating parent
compound of doped high-$T_{c}$ superconductors, using \emph{in situ}
angle-resolved photoemission spectroscopy on thin films. The data compare
favorably overall with density functional theory calculations within the local
density approximation, demonstrating that electron correlations are weak. The
bands exhibit Brillouin zone folding consistent with known BiO$_{6}$ breathing
distortions. Though the distortions are often thought to coincide with
Bi$^{3+}$/Bi$^{5+}$ charge ordering, core level spectra show that bismuth is
monovalent. We further demonstrate that the bands closest to the Fermi level
are primarily oxygen derived, while the bismuth $6s$ states mostly contribute
to dispersive bands at deeper binding energy. The results support a model of
Bi-O charge transfer in which hole pairs are localized on combinations of the O
$2p$ orbitals.


title:
Exact Energy Computation of the One Component Plasma on a Sphere for
  Even Values of the Coupling Parameter

abstract:
  The two dimensional one component plasma 2dOCP is a classical system
consisting of $N$ identical particles with the same charge $q$ confined in a
two dimensional surface with a neutralizing background. The Boltzmann factor at
temperature $T$ may be expressed as a Vandermonde determinant to the power
$\Gamma=q^2/(k_B T)$. Several statistical properties of the 2dOCP have been
studied by expanding the Boltzmann factor in the monomial basis for even values
of $\Gamma$. In this work, we use this formalism to compute the energy of the
2dOCP on a sphere. Using the same approach the entropy is computed. The entropy
as well as the free energy in the thermodynamic limit have a universal
finite-size correction term $\frac{\chi}{12}\log N$, where $\chi=2$ is the
Euler characteristic of the sphere. A non-recursive formula for coefficients of
monomial functions expansion is used for exploring the energy as well as
structural properties for sufficiently large values of $\Gamma$ to appreciate
the crystallization features for $N=2,3,\ldots,9$ particles. Finally, we make a
brief comparison between the exact and numerical energies obtained with the
Metropolis method for even values of $\Gamma$.


title:
Probabilistic-Numerical assessment of pyroclastic current hazard at
  Campi Flegrei and Naples city: Multi-VEI scenarios as a tool for full-scale
  risk management

abstract:
  The Campi Flegrei volcanic field (Italy) poses very high risk to the highly
urbanized Neapolitan area. Eruptive history was dominated by explosive activity
producing pyroclastic currents (PDCs; (Proclastic Density Currents) ranging in
scale from localized base surges to regional flows. Here we apply probabilistic
numerical simulation approaches to produce PDC hazard maps, based on a
comprehensive spectrum of flow properties and vent locations. These maps and
provide all probable Volcanic Explosivity Index (VEI) scenarios from different
source vents in the caldera, relevant for risk management planning. For each
VEI scenario, we report the conditional probability for PDCs (i.e., the
probability for a given area to be affected by the passage of PDCs) and related
dynamic pressure. Model results indicate that PDCs from VEI<4 events would be
confined within the Campi Flegrei caldera, PDC propagation being impeded by the
northern and eastern caldera walls. Conversely, PDCs from VEI 4-5 events could
invade a wide area beyond the northern caldera rim, as well as part of the
Naples metropolitan area to the east. A major controlling factor of PDC
dispersal is represented by the location of the vent area. PDCs from the
potentially largest eruption scenarios (analogous to the ~15 ka, VEI 6
Neapolitan Yellow Tuff or even the ~39 ka, VEI 7 Campanian Ignimbrite extreme
event) would affect a large part of the Campanian Plain to the north and the
city of Naples to the east. Thus, in case of renewal of eruptive activity at
Campi Flegrei, up to 3 million people will be potentially exposed to volcanic
hazard, pointing out the urgency of an emergency plan. Considering the present
level of uncertainty in forecasting the future eruption type, size and location
we suggest that appropriate planning measures should face at least the VEI 5
reference scenario (at least 2 occurrences documented in the last 10 ka)


title: Orbifold Slope Rational-Connectedness

abstract:
  The notion of 'slope rational connectedness' is introduced in the context of
smooth orbifold pairs. The main result parallels the characterization of the
rational connectedness of projective manifolds in terms of either the
non-existence of holomorphic covariant tensors, or of absence of fibrations
onto manifolds with pseudo-effective canonical bundle, or of existence of
movable classes for which the minimal slope of the tangent bundle is positive.
We then use this result to construct the `rational quotient map' in orbifold
category.


title:
Topology Sorting and Characterization of Folded Polymers Using
  Nano-pores

abstract:
  Here we report on the translocation of folded polymers through nano-pores
using molecular dynamic simulations. Two cases are studied; one in which a
folded molecule unfolds upon passage and one in which the folding remains
intact as the molecule passes through the nano-pore. The topology of a folded
polymer chain is defined as the arrangement of the intramolecular contacts,
known as circuit topology. In the case where intramolecular contacts remain
intact, we show that the dynamics of passage through a nano-pore varies for
molecules with differing topologies: a phenomenon that can be exploited to
enrich certain topologies in mixtures. We find that the nano-pore allows
reading of topology for short chains. Moreover, when the passage is coupled
with unfolding, the nano-pore enables discrimination between pure states, i.e.,
states for which the majority of contacts are arranged identically. In this
case, as we show here, it is also possible to read the positions of the contact
sites along a chain. Our results demonstrate the applicability of nano-pore
technology to characterize and sort molecules based on their topology.


title: Electromagnetic radiation of charged particles in stochastic motion

abstract:
  The study of the Brownian motion of a charged particle in electric and
magnetic fields fields has many important applications in plasma and heavy ions
physics, as well as in astrophysics. In the present paper we consider the
electromagnetic radiation properties of a charged non-relativistic particle in
the presence of electric and magnetic fields, of an exterior
non-electromagnetic potential, and of a friction and stochastic force,
respectively. We describe the motion of the charged particle by a Langevin and
generalized Langevin type stochastic differential equation. We investigate in
detail the cases of the Brownian motion with or without memory in a constant
electric field, in the presence of an external harmonic potential, and of a
constant magnetic field. In all cases the corresponding Langevin equations are
solved numerically, and a full description of the spectrum of the emitted
radiation and of the physical properties of the motion is obtained. The Power
Spectral Density (PSD) of the emitted power is also obtained for each case,
and, for all considered oscillating systems, it shows the presence of peaks,
corresponding to certain intervals of the frequency.


title:
Stability analysis and stabilization of stochastic linear impulsive,
  switched and sampled-data systems under dwell-time constraints

abstract:
  Impulsive systems are a very flexible class of systems that can be used to
represent switched and sampled-data systems. We propose to extend here the
previously obtained results on deterministic impulsive systems to the
stochastic setting. The concepts of mean-square stability and dwell-times are
utilized in order to formulate relevant stability conditions for such systems.
These conditions are formulated as convex clock-dependent linear matrix
inequality conditions that are applicable to robust analysis and control
design, and are verifiable using discretization or sum of squares techniques.
Stability conditions under various dwell-time conditions are obtained and
non-conservatively turned into state-feedback stabilization conditions. The
results are finally applied to the analysis and control of stochastic
sampled-data systems. Several comparative examples demonstrate the accuracy and
the tractability of the approach.


title: Learning quantum annealing

abstract:
  We propose and develop a new procedure, whereby a quantum system can learn to
anneal to a desired ground state. We demonstrate successful learning to produce
an entangled state for a two-qubit system, then demonstrate generalizability to
larger systems. The amount of additional learning necessary decreases as the
size of the system increases. Because current technologies limit measurement of
the states of quantum annealing machines to determination of the average spin
at each site, we then construct a "broken pathway" between the initial and
desired states, at each step of which the average spins are nonzero, and show
successful learning of that pathway. Using this technique we show we can direct
annealing to multiqubit GHZ and W states, and verify that we have done so.
Because quantum neural networks are robust to noise and decoherence we expect
our method to be readily implemented experimentally; we show some preliminary
results which support this.


title: There is no bound on sizes of indecomposable Banach spaces

abstract:
  Assuming the generalized continuum hypothesis we construct arbitrarily big
indecomposable Banach spaces. i.e., such that whenever they are decomposed as
$X\oplus Y$, then one of the closed subspaces $X$ or $Y$ must be finite
dimensional. It requires alternative techniques compared to those which were
initiated by Gowers and Maurey or Argyros with the coauthors. This is because
hereditarily indecomposable Banach spaces always embed into $\ell_\infty$ and
so their density and cardinality is bounded by the continuum and because dual
Banach spaces of densities bigger than continuum are decomposable by a result
due to Heinrich and Mankiewicz.
  The obtained Banach spaces are of the form $C(K)$ for some compact connected
Hausdorff space and have few operators in the sense that every linear bounded
operator $T$ on $C(K)$ for every $f\in C(K)$ satisfies $T(f)=gf+S(f)$ where
$g\in C(K)$ and $S$ is weakly compact or equivalently strictly singular. In
particular, the spaces carry the structure of a Banach algebra and in the
complex case even the structure of a $C^*$-algebra.


title:
Identifiability of Electrical and Heat Transfer Parameters Using Coupled
  Boundary Measurements

abstract:
  In this paper, we show that a hybrid method using coupled boundary
measurements can determine electrical conductivity, thermal conductivity, and
the product of heat capacity and heat density within a bounded domain on the
plane uniquely up to a boundary-fixing diffromorphism.


title:
Probe of Multi-electron Dynamics in Xenon by Caustics in High Order
  Harmonic Generation

abstract:
  We investigated the giant resonance in Xenon by high-order harmonic
generation spectroscopy driven by a two-color field. The addition of a
non-perturbative second harmonic component parallel to the driving field breaks
the symmetry between neighboring sub-cycles resulting in the appearance of
spectral caustics at two distinct cut-off energies. By controlling the phase
delay between the two color components it is possible to tailor the harmonic
emission in order to amplify and isolate the spectral feature of interest. In
this paper we demonstrate how this control scheme can be used to investigate
the role of electron correlations that give birth to the giant resonance in
Xenon. The collective excitations of the giant dipole resonance in Xenon
combined with the spectral manipulation associated with the two color driving
field allow to see features that are normally not accessible and to obtain a
quantitative good agreement between the experimental results and the
theoretical predictions.


title:
The 750 GeV diphoton excess in unified $SU(2)_L\times SU(2)_R\times
  SU(4)$ models from noncommutative geometry

abstract:
  We discuss a possible interpretation of the $750$ GeV diphoton resonance,
recently reported at the LHC, within a class of $SU(2)_L\times SU(2)_R\times
SU(4)$ models with gauge coupling unification. The unification is imposed by
the underlying non-commutative geometry (NCG), which in these models is
extended to a left-right symmetric completion of the Standard Model (SM).
Within such \textit{unified} $SU(2)_L\times SU(2)_R\times SU(4)$ models the
Higgs content is restrictively determined from the underlying NCG, instead of
being arbitrarily selected. We show that the observed cross sections involving
the $750$ GeV diphoton resonance could be realized through a SM singlet scalar
field accompanied by colored scalars, present in these unified models. In view
of this result we discuss the underlying rigidity of these models in the NCG
framework and the wider implications of the NCG approach for physics beyond the
SM.


title:
Efficiency calculation of thermoelectric generator using temperature
  dependent material's properties

abstract:
  Accurate measurement of efficiency for thermoelectric generator (TEG) is of
great importance for materials research and development. Approximately all the
parameters of a material are temperature dependent, so we can't directly apply
the $\eta_\text{max}$ formula for efficiency calculation in the large
temperature range. To overcome that problem, we tried to calculate the
efficiency of TEG by dividing large working temperature range into a number of
small temperature difference. The aim is to make temperature dependent
parameter to be constant for that small temperature range. Using maximum
individual efficiency of each segment obtained by $\eta_\text{max}$ in the
equation of $\eta_\text{overall}$, which gives overall efficiency. The
$\eta_\text{overall}$ of TEG using $Bi_2Te_3$ and $TAGS$ as thermoelectric
materials come out to be $7.1\%$ and $8.94\%$, respectively, which is close to
experimental results. For the high-temperature region, we have used $SiGe$
material in TEG and found out $\eta_\text{overall}=3.5\%$. The cumulative
efficiency obtained by keeping one end temperature fixed with another end
varying can be applied in real life application, i.e. automobile sector. The
present work provides a simple way for the design engineers to calculate the
efficiency of TEG by using the temperature dependent materials parameters like
thermal conductivity, electrical conductivity, and Seebeck coefficient on which
$z\bar{T}$ depends.


title: Normal-order reduction grammars

abstract:
  We present an algorithm which, for given $n$, generates an unambiguous
regular tree grammar defining the set of combinatory logic terms, over the set
$\{S,K\}$ of primitive combinators, requiring exactly $n$ normal-order
reduction steps to normalize. As a consequence of Curry and Feys's
standardization theorem, our reduction grammars form a complete syntactic
characterization of normalizing combinatory logic terms. Using them, we provide
a recursive method of constructing ordinary generating functions counting the
number of $S K$-combinators reducing in $n$ normal-order reduction steps.
Finally, we investigate the size of generated grammars, giving a primitive
recursive upper bound.


title: Neutron resonances in planar waveguides

abstract:
  Results of experimental investigations of a neutron resonances width in
planar waveguides using the time-of-flight reflectometer REMUR of the IBR-2
pulsed reactor are reported and comparison with theoretical calculations is
presented. The intensity of the neutron microbeam emitted from the waveguide
edge was registered as a function of the neutron wavelength and the incident
beam angular divergence. The possible applications of this method for the
investigations of layered nanostructures are discussed.


title:
MIRO-like oscillations of magneto-resistivity in GaAs heterostructures
  induced by THz radiation

abstract:
  We report on the study of terahertz radiation induced MIRO-like oscillations
of magneto-resistivity in GaAs heterostructures. Our experiments provide an
answer on two most intriguing questions - effect of radiation helicity and the
role of the edges - yielding crucial information for understanding of the MIRO
origin. Moreover, we demonstrate that the range of materials exhibiting
radiation-induced magneto-oscillations can be largely extended by using
high-frequency radiation.


title: Overresolving in the Laplace domain for convolution quadrature methods

abstract:
  Convolution quadrature (CQ) methods have enjoyed tremendous interest in
recent years as an efficient tool for solving time-domain wave problems in
unbounded domains via boundary integral equation techniques. In this paper we
consider CQ type formulations for the parallel space-time evaluation of
multistep or stiffly accurate Runge-Kutta rules for the wave equation. In
particular, we decouple the number of Laplace domain solves from the number of
time steps. This allows to overresolve in the Laplace domain by computing more
Laplace domain solutions solutions than there are time steps. We use techniques
from complex approximation theory to analyse the error of the CQ approximation
of the underlying time-stepping rule when overresolving in the Laplace domain
and show that the performance is intimately linked to the location of the poles
of the solution operator. Several examples using boundary integral equation
formulations in the Laplace domain are presented to illustrate the main
results.


title: Another Approach to Test Gravity around a Black Hole

abstract:
  Pulsars orbiting around the black hole at our galactic center provide us a
unique testing site for gravity. In this work, we propose an approach to probe
the gravity around the black hole introducing two phenomenological parameters
which characterize deviation from the vacuum Einstein theory. The two
phenomenological parameters are associated with the energy momentum tensor in
the framework of the Einstein theory. Therefore, our approach can be regarded
as the complement to the parametrized post-Newtonian framework in which
phenomenological parameters are introduced for deviation of gravitational
theories from general relativity. In our formulation, we take the possibility
of existence of a relativistic and exotic matter component into account. Since
the pulsars can be regarded as test particles, as the first step, we consider
geodesic motion in the system composed of a central black hole and a perfect
fluid whose distribution is static and spherically symmetric. It is found that
the mass density of the fluid and a parameter of the equation of state can be
determined with precision with $0.1\%$ if the density on the pulsar orbit is
larger than $10^{-9}~{\rm g/cm^3}$.


title:
Gravitational waves in Friedman-Lemaitre-Robertson-Walker cosmology,
  material perturbations and cosmological rotation, and the Huygens principle

abstract:
  We analyze propagation equations for the polar modes of gravitational waves
in cosmological space-times. We prove that polar gravitational waves must
perturb the density and non-azimuthal components of the velocity of material
medium of the Friedman-Lemaitre-Robertson-Walker spacetimes. Axial
gravitational waves can influence only the azimuthal velocity, leading to local
cosmological rotation. The whole gravitational dynamics reduces to the single
"master equation" that has the same form for polar and axial modes. That allows
us to conclude that the status of the Huygens principle is the same for axial
and polar gravitational waves. In particular, this principle is valid exactly
in radiation spacetimes with the vanishing cosmological constant, and it is
broken otherwise.


title:
Accelerated expansion of the Universe without an inflaton and resolution
  of the initial singularity from Group Field Theory condensates

abstract:
  We study the expansion of the Universe using an effective Friedmann equation
obtained from the dynamics of GFT (Group Field Theory) isotropic condensates.
The evolution equations are classical, with quantum correction terms to the
Friedmann equation given in the form of effective fluids coupled to the
emergent classical background. The occurrence of a bounce, which resolves the
initial spacetime singularity, is shown to be a general property of the model.
A promising feature of this model is the occurrence of an era of accelerated
expansion, without the need to introduce an inflaton field with an
appropriately chosen potential. We discuss possible viability issues of this
scenario as an alternative to inflation.


title:
Accurate principal component analysis via a few iterations of
  alternating least squares

abstract:
  A few iterations of alternating least squares with a random starting point
provably suffice to produce nearly optimal spectral- and Frobenius-norm
accuracies of low-rank approximations to a matrix; iterating to convergence is
unnecessary. Thus, software implementing alternating least squares can be
retrofitted via appropriate setting of parameters to calculate nearly optimally
accurate low-rank approximations highly efficiently, with no need for
convergence.


title: Spatial logic of modal mu-calculus and tangled closure operators

abstract:
  There has been renewed interest in recent years in McKinsey and Tarski's
interpretation of modal logic in topological spaces and their proof that S4 is
the logic of any separable dense-in-itself metric space. Here we extend this
work to the modal mu-calculus and to a logic of tangled closure operators that
was developed by Fern\'andez-Duque after these two languages had been shown by
Dawar and Otto to have the same expressive power over finite transitive Kripke
models. We prove that this equivalence remains true over topological spaces.
  We establish the finite model property in Kripke semantics for various
tangled closure logics with and without the universal modality $\forall$. We
also extend the McKinsey--Tarski topological `dissection lemma'. These results
are used to construct a representation map (also called a d-p-morphism) from
any dense-in-itself metric space $X$ onto any finite connected locally
connected serial transitive Kripke frame.
  This yields completeness theorems over $X$ for a number of languages: (i) the
modal mu-calculus with the closure operator $\Diamond$; (ii) $\Diamond$ and the
tangled closure operators $\langle t \rangle$; (iii) $\Diamond,\forall$; (iv)
$\Diamond,\forall,\langle t \rangle$; (v) the derivative operator $\langle d
\rangle$; (vi) $\langle d \rangle$ and the associated tangled closure operators
$\langle dt \rangle$; (vii) $\langle d \rangle,\forall$; (viii) $\langle d
\rangle,\forall,\langle dt \rangle$. Soundness also holds, if: (a) for
languages with $\forall$, $X$ is connected; and (b) for languages with $\langle
d \rangle$, $X$ validates the well known axiom $\mathrm{G}_1$. For countable
languages without $\forall$, we prove strong completeness. We also show that in
the presence of $\forall$, strong completeness fails if $X$ is compact and
locally connected.


title:
Improved proper motion determinations for 15 open clusters based on the
  UCAC4 catalog

abstract:
  The proper motions of 15 nearby (d < 1 kpc) open clusters were recalculated
using data from the UCAC4 catalog. Only evolved or main sequence stars inside a
certain radius from the center of the cluster were used. The results differ
significantly from the ones presented by Dias et al. (2014). This could be
explained by the different approach to taking the field star contamination into
account. The present work aims to emphasize the importance of applying
photometric criteria for the calculation of open cluster proper motions.