title: A two-scale Stefan problem arising in a model for tree sap exudation

abstract:
  The study of tree sap exudation, in which a (leafless) tree generates
elevated stem pressure in response to repeated daily freeze-thaw cycles, gives
rise to an interesting multi-scale problem involving heat and multiphase
liquid/gas transport. The pressure generation mechanism is a cellular-level
process that is governed by differential equations for sap transport through
porous cell membranes, phase change, heat transport, and generation of osmotic
pressure. By assuming a periodic cellular structure based on an appropriate
reference cell, we derive an homogenized heat equation governing the global
temperature on the scale of the tree stem, with all the remaining physics
relegated to equations defined on the reference cell. We derive a corresponding
strong formulation of the limit problem and use it to design an efficient
numerical solution algorithm. Numerical simulations are then performed to
validate the results and draw conclusions regarding the phenomenon of sap
exudation, which is of great importance in trees such as sugar maple and a few
other related species. The particular form of our homogenized temperature
equation is obtained using periodic homogenization techniques with two-scale
convergence, which we investigate theoretically in the context of a simpler
two-phase Stefan-type problem corresponding to a periodic array of melting
cylindrical ice bars with a constant thermal diffusion coefficient. For this
reduced model, we prove results on existence, uniqueness and convergence of the
two-scale limit solution in the weak form, clearly identifying the missing
pieces required to extend the proofs to the fully nonlinear sap exudation
model. Numerical simulations of the reduced equations are then compared with
results from the complete sap exudation model.


title:
Compositional asymmetry of disordered structure: Role of spatial
  constraint

abstract:
  When spatial constraint for the constituents (e.g., atom or particle) of
system is once given, disordered structure for non-interacting system in
equilibrium states is symmetric with respect to equiatomic composition.
Meanwhile, when the interaction between constituents is introduced, this
symmetry is typically broken, naturally appearing compositional asymmetry.
Although this asymmetry, depending on temperature, comes from multibody
interactions in the system, we here clarify that the asymmetry near equiatomic
composition can be universally well-characterized by two specially selected
microscopic structure, which can be known a priori without any information
about interactions or temperature: The key role is the class of spatial
constraint. Based on the facts, we provide analytical expression of temperature
dependence of disordered structure, and demonstrate its validity and
applicability by predicting short-range order parameters of practical alloys
compared with full thermodynamic simulation.


title:
Tracking galaxy evolution through low frequency radio continuum
  observations using SKA and Citizen-science Research using Multi-wavelength
  data

abstract:
  We present a review on galaxy black hole co-evolution through merger, star
formation and AGN-jet feedback. We highlight results on transitional galaxies
(e.g. NGC1482, NGC6764, NGC3801, Speca, RAD-18 etc.) which has data from Giant
Meterwave Radio Telescope (GMRT) and other sub-mm, IR, optical, UV and X-ray
telescopes. The `smoking gun' relic-evidences of past AGN-jet feedback which is
believed to have quenched star formation in transitional galaxies are still
missing. Relic radio lobes, as old as a few hundred Myr, can be best detected
at low radio frequencies with the GMRT, LOFAR and in future SKA. However,
similar relic evidences of quasar activities, known as `Hanny's Voorwerp'
discovered by Galaxy Zoo in optical data, are only around a few tens of
thousand years old. More discoveries are needed to match these time-scales with
time since the decline of star formation in transitional galaxies. Such faint
fuzzy relic emissions in optical and angular-scale sensitive radio
interferometric images can be discovered most efficiently by citizen-scientists
but with a formal training. We describe RAD@home, the only Indian
citizen-science research project in astronomy which takes such a modified
approach. We present interesting objects, discovered from the TIFR GMRT Sky
Survey (TGSS) by 69 trained citizen-scientists or e-astronomers, like relic
radio lobes, episodic radio galaxies, jet-galaxy interaction, bent radio galaxy
in filament etc.. This model can provide an equal opportunity of
academic-growth to people even in the under-developed regions where we always
need to establish our optical and radio telescopes. This can expand the
research-activity of city-based research-institutes beyond their four brick
walls, and alleviate various socio-economic and geo-political constraints on
growth of citizens located in remote areas. #RADatHomeIndia #ABCDresearch


title: Experiments with POS Tagging Code-mixed Indian Social Media Text

abstract:
  This paper presents Centre for Development of Advanced Computing Mumbai's
(CDACM) submission to the NLP Tools Contest on Part-Of-Speech (POS) Tagging For
Code-mixed Indian Social Media Text (POSCMISMT) 2015 (collocated with ICON
2015). We submitted results for Hindi (hi), Bengali (bn), and Telugu (te)
languages mixed with English (en). In this paper, we have described our
approaches to the POS tagging techniques, we exploited for this task. Machine
learning has been used to POS tag the mixed language text. For POS tagging,
distributed representations of words in vector space (word2vec) for feature
extraction and Log-linear models have been tried. We report our work on all
three languages hi, bn, and te mixed with en.


title: Subquadratic Submodular Function Minimization

abstract:
  Submodular function minimization (SFM) is a fundamental discrete optimization
problem which generalizes many well known problems, has applications in various
fields, and can be solved in polynomial time. Owing to applications in computer
vision and machine learning, fast SFM algorithms are highly desirable. The
current fastest algorithms [Lee, Sidford, Wong, FOCS 2015] run in $O(n^{2}\log
nM\cdot\textrm{EO} +n^{3}\log^{O(1)}nM)$ time and $O(n^{3}\log^{2}n\cdot
\textrm{EO} +n^{4}\log^{O(1)}n$) time respectively, where $M$ is the largest
absolute value of the function (assuming the range is integers) and
$\textrm{EO}$ is the time taken to evaluate the function on any set. Although
the best known lower bound on the query complexity is only $\Omega(n)$, the
current shortest non-deterministic proof certifying the optimum value of a
function requires $\Theta(n^{2})$ function evaluations.
  The main contribution of this paper are subquadratic SFM algorithms. For
integer-valued submodular functions, we give an SFM algorithm which runs in
$O(nM^{3}\log n\cdot\textrm{EO})$ time giving the first nearly linear time
algorithm in any known regime. For real-valued submodular functions with range
in $[-1,1]$, we give an algorithm which in
$\tilde{O}(n^{5/3}\cdot\textrm{EO}/\varepsilon^{2})$ time returns an
$\varepsilon$-additive approximate solution. At the heart of it, our algorithms
are projected stochastic subgradient descent methods on the Lovasz extension of
submodular functions where we crucially exploit submodularity and data
structures to obtain fast, i.e. sublinear time subgradient updates. . The
latter is crucial for beating the $n^{2}$ bound as we show that algorithms
which access only subgradients of the Lovasz extension, and these include the
theoretically best algorithms mentioned above, must make $\Omega(n)$
subgradient calls (even for functions whose range is $\{-1,0,1\}$).


title:
Integration of a $^6$LiInSe$_2$ Thermal Neutron Detector into a CubeSat
  Instrument

abstract:
  We present a preliminary design for a novel neutron detection system that is
compact, lightweight, and low power consuming, utilizing the CubeSat platform
making it suitable for space-based applications. This is made possible using
the scintillating crystal lithium indium diselenide ($^6$LiInSe$_2$), the first
crystal to include $^6$Li in the crystalline structure, and a silicon avalanche
photodiode (Si-APD). The schematics of this instrument are presented as well as
the response of the instrument to initial testing under alpha radiation. A
principal aim of this work is to demonstrate the feasibility of such a neutron
detection system within a CubeSat platform. The entire end-to-end system
presented here is 10 cm x 10 cm x 15 cm, weighs 670 grams and requires 5 Volts
direct current at 3 Watts.


title: Confidence intervals centered on bootstrap smoothed estimators

abstract:
  Bootstrap smoothed (bagged) parameter estimators have been proposed as an
improvement on estimators found after preliminary data-based model selection.
The key result of Efron (2014) is a very convenient and widely applicable
formula for a delta method approximation to the standard deviation of the
bootstrap smoothed estimator. This approximation provides an easily computed
guide to the accuracy of this estimator. In addition, Efron (2014) proposed a
confidence interval centered on the bootstrap smoothed estimator, with width
proportional to the estimate of this approximation to the standard deviation.
We evaluate this confidence interval in the scenario of two nested linear
regression models, the full model and a simpler model, and a preliminary test
of the null hypothesis that the simpler model is correct. We derive
computationally convenient expressions for the ideal bootstrap smoothed
estimator and the coverage probability and expected length of this confidence
interval. In terms of coverage probability, this confidence interval
outperforms the post-model-selection confidence interval with the same nominal
coverage and based on the same preliminary test. We also compare the
performance of confidence interval centered on the bootstrap smoothed
estimator, in terms of expected length, to the usual confidence interval, with
the same minimum coverage probablility, based on the full model.


title: A quantum analogue of generalized cluster algebras

abstract:
  We define a quantum analogue of a class of generalized cluster algebras which
can be viewed as a generalization of quantum cluster algebras defined in
\cite{berzel}. In the case of rank two, we extend some structural results from
the classical theory of generalized cluster algebras obtained in
\cite{CS}\cite{rupel} to the quantum case.


title: Pyramids and cootie catchers: new massless fermions in 2D materials

abstract:
  Dirac-like electronic states are the main engines powering the tremendous
advances in research of graphene, topological insulators and other materials
with these states. Zero effective mass, high carrier mobility and numerous
applications are some consequences of linear dispersion that distinguishes
Dirac states. Here we report a new class of linear electronic bands in
two-dimensional materials with zero effective mass and sharp band edges never
seen in solid state matter before, and predict stable materials with such
electronic structure utilizing symmetry group analysis and ab initio approach.
We make a full classification of completely linear bands in two-dimensional
materials and find that only two classes exist: Dirac fermions on one hand and
pyramidal-like and cootie catcher-like states on the other hand. The new class
supports zero effective mass and hence high carrier mobility similar to that of
graphene, anisotropic electronic properties like that of phosphorene, and
robustness of states with respect to electronic correlations.


title: Efimov Physics: a review

abstract:
  This article reviews theoretical and experimental advances in Efimov physics,
an array of quantum few-body and many-body phenomena arising for particles
interacting via short-range resonant interactions, that is based on the
appearance of a scale-invariant three-body attraction theoretically discovered
by Vitaly Efimov in 1970. This three-body effect was originally proposed to
explain the binding of nuclei such as the triton and the Hoyle state of
carbon-12, and later considered as a simple explanation for the existence of
some halo nuclei. It was subsequently evidenced in trapped ultra-cold atomic
clouds and in diffracted molecular beams of gaseous helium. These experiments
revealed that the previously undetermined three-body parameter introduced in
the Efimov theory to stabilise the three-body attraction typically scales with
the range of atomic interactions. The few- and many-body consequences of the
Efimov attraction have been since investigated theoretically, and are expected
to be observed in a broader spectrum of physical systems.

categories: quant-ph cond-mat.quant-gas nucl-th physics.atom-ph


title: The design of efficient algorithms for enumeration

abstract:
  Many algorithms have been developed for enumerating various combinatorial
objects in time exponentially less than the number of objects. Two common
classes of algorithms are dynamic programming and the transfer matrix method.
This paper covers the design and implementation of such algorithms.
  A host of general techniques for improving efficiency are described. Three
quite different example problems are used for examples: 1324 pattern avoiding
permutations, three-dimensional polycubes, and two-dimensional directed
animals.
  For those new to the field, this paper is designed to be an introduction to
many of the tricks for producing efficient enumeration algorithms. For those
more experienced, it will hopefully help them understand the interrelationship
and implications of a variety of techniques, many or most of which will be
familiar. The author certainly found his understanding improved as a result of
writing this paper.


title:
Decoupling of hyperfine structure of Cs $D_1$ line in strong magnetic
  field studied by selective reflection from a nanocell

abstract:
  Decoupling of total electronic and nuclear spin moments of Cs atoms in
external magnetic field for the case of atomic $D_1$ line, leading to onset of
the hyperfine Paschen-Back regime has been studied theoretically and
experimentally. Selective reflection of laser radiation from an interface of
dielectric window and atomic vapor confined in a nanocell with 300 nm gap
thickness was implemented for the experimental studies. The real time
derivative of selective reflection signal with a frequency position coinciding
with atomic transitions was used in measurements, providing $\sim$ 40 MHz
spectral resolution and linearity of signal response in respect to transition
probability. Behavior of 28 individual Zeeman transitions in a wide range of
longitudinal magnetic field (0 - 6 kG) has been tracked under excitation of Cs
vapor by a low-intensity $\sigma^+$- polarized cw laser radiation. For $B\ge
6~$kG, only 8 transitions with nearly equal probabilities and the same
frequency slope remained in the spectrum, which is a manifestation of the
hyperfine Paschen-Back regime. The obtained experimental results are consistent
with numerical modeling. Due to small divergence of selective reflection
signal, as well as sub-wavelength thickness and sub-Doppler spectral linewidth
inherent to nanocell, the employed technique can be used for distant remote
sensing of magnetic field with high spatial and $B$-field resolution.


title: Geometry of cuspidal edges with boundary

abstract:
  We study differential geometric properties of cuspidal edges with boundary.
There are several differential geometric invariants which are related with the
behavior of the boundary in addition to usual differential geometric invariants
of cuspidal edges. We study the relation of these invariants with several other
invariants.


title:
Valuation theoretic methods in the birational geometry of algebraic
  varieties

abstract:
  In this paper, we give a valuation formula for rational top differential
forms of function fields in characteristic zero for arbitrary Abhyankar places
generalizing the classical valuation at prime divisors. This enables us to
define log discrepancies for log pairs for arbitrary Abhyankar places. If the
Abhyankar place has dimension greater than zero we restrict rational top
differential forms with valuation zero to the residue field of the Abhyankar
place, generalizing the classical restriction of a top differential form with a
simple pole along a smooth divisor. This opens up the door to generalize the
classical adjunction machinery to arbitrary Abhyankar places.


title: Statistical Study of Visual Binaries

abstract:
  In this paper, some statistical distributions of wide pairs included in
Double Star Catalogue are investigated. Frequency distributions and testing
hypothesis are derived for some basic parameters of visual binaries. The
results reached indicate that, it was found that the magnitude difference is
distributed exponentially, which means that the majority of the component of
the selected systems is of the same spectral type. The distribution of the mass
ratios is concentrated about 0.7 which agree with Salpeter mass function. The
distribution of the linear separation appears to be exponentially, which
contradict with previous studies for close binaries.


title:
Validation of a Scaling Law for the Coronal Magnetic Field Strengths and
  Loop Lengths of Solar and Stellar Flares

abstract:
  Shibata & Yokoyama (1999, 2002) proposed a method of estimating the coronal
magnetic field strengths ($B$) and magnetic loop lengths ($L$) of solar and
stellar flares, on the basis of magnetohydrodynamic simulations of the magnetic
reconnection model. Using the scaling law provided by Shibata & Yokoyama (1999,
2002), $B$ and $L$ are obtained as functions of the emission measure
($EM=n^2L^3$) and temperature ($T$) at the flare peak. Here, $n$ is the coronal
electron density of the flares. This scaling law enables the estimation of $B$
and $L$ for unresolved stellar flares from the observable physical quantities
$EM$ and $T$, which is helpful for studying stellar surface activities. To
apply this scaling law to stellar flares, we discuss its validity for spatially
resolved solar flares. $EM$ and $T$ were calculated from GOES soft X-ray flux
data, and $B$ and $L$ are theoretically estimated using the scaling law. For
the same flare events, $B$ and $L$ were also observationally estimated with
images taken by Solar Dynamics Observatory (SDO)/ Helioseismic and Magnetic
Imager (HMI) Magnetogram and Atmospheric Imaging Assembly (AIA) 94{\AA} pass
band. As expected, a positive correlation was found between the theoretically
and observationally estimated values. We interpret this result as indirect
evidence that flares are caused by magnetic reconnection. Moreover, this
analysis makes us confident in the validity of applying this scaling law to
stellar flares as well as solar flares.


title: Long-range Correlation and Market Segmentation in Bond Market

abstract:
  This paper looks into the analysis of the long-range auto-correlations and
cross-correlations in bond market. Based on Detrended Moving Average (DMA)
method, empirical results present a clear evidence of long-range persistence
that exists in one year scale. The degree of long-range correlation related to
maturities has an upward tendency with a peak in short term. These findings
confirm the expectations of fractal market hypothesis (FMH). Furthermore, we
have developed a method based on a complex network to study the long-range
cross-correlation structure and apply it to our data, and found a clear pattern
of market segmentation in the long run. We also detected the nature of
long-range correlation in the sub-period 2007 to 2012 and 2011 to 2016. The
result from our research shows that long-range auto-correlations are decreasing
in the recent years while long-range cross-correlations are strengthening.


title:
On B-type open-closed Landau-Ginzburg theories defined on Calabi-Yau
  Stein manifolds

abstract:
  We consider the bulk algebra and topological D-brane category arising from
the differential model of the open-closed B-type topological Landau-Ginzburg
theory defined by a pair $(X,W)$, where $X$ is a non-compact Calabi-Yau
manifold and $W$ has compact critical set. When $X$ is a Stein manifold (but
not restricted to be a domain of holomorphy), we extract equivalent
descriptions of the bulk algebra and of the category of topological D-branes
which are constructed using only the analytic space associated to $X$. In
particular, we show that the D-brane category is described by projective matrix
factorizations defined over the ring of holomorphic functions of $X$. We also
discuss simplifications of the analytic models which arise when $X$ is
holomorphically parallelizable and illustrate these analytic models in a few
classes of examples.


title: Chiral phase transition of QCD with $N_f=2+1$ flavors from holography

abstract:
  Chiral phase transition for three-flavor $N_f=2+1$ QCD with $m_u=m_d\neq m_s$
is investigated in a modified soft-wall holographic QCD model. Solving
temperature dependent chiral condensates from equations of motion of the
modified soft-wall model, we extract the quark mass dependence of the order of
chiral phase transition in the case of $N_f=2+1$, and the result is in
agreement with the "Colombia Plot", which is summarized from lattice
simulations and other non-perturbative methods. First order phase transition is
observed around the three flavor chiral limit $m_{u/d}=0, m_{s}=0$, while at
sufficient large quark masses it turns to be a crossover phase transition. The
first order and crossover regions are separated by a second order phase
transition line. The second order line is divided into two parts by the
$m_{u/d}=m_s$ line, and the $m_s$ dependence of the transition temperature in
these two parts are totally contrast, which might indicate that the two parts
are governed by different universality classes.


title: The Nash equilibrium of forest ecosystems

abstract:
  To find the possible equilibrium states of forest ecosystems one are
suggested to use the theory of differential games. At within the 4-tier model
of mosaic forest communities it established the existence of the Nash
equilibrium states in such ecosystems


title: Robust Gait Recognition by Integrating Inertial and RGBD Sensors

abstract:
  Gait has been considered as a promising and unique biometric for person
identification. Traditionally, gait data are collected using either color
sensors, such as a CCD camera, depth sensors, such as a Microsoft Kinect, or
inertial sensors, such as an accelerometer. However, a single type of sensors
may only capture part of the dynamic gait features and make the gait
recognition sensitive to complex covariate conditions, leading to fragile
gait-based person identification systems. In this paper, we propose to combine
all three types of sensors for gait data collection and gait recognition, which
can be used for important identification applications, such as identity
recognition to access a restricted building or area. We propose two new
algorithms, namely EigenGait and TrajGait, to extract gait features from the
inertial data and the RGBD (color and depth) data, respectively. Specifically,
EigenGait extracts general gait dynamics from the accelerometer readings in the
eigenspace and TrajGait extracts more detailed sub-dynamics by analyzing 3D
dense trajectories. Finally, both extracted features are fed into a supervised
classifier for gait recognition and person identification. Experiments on 50
subjects, with comparisons to several other state-of-the-art gait-recognition
approaches, show that the proposed approach can achieve higher recognition
accuracy and robustness.


title:
A critical point in Sr2-xIrO4 and less distorted IrO6 octahedra induced
  by deep Sr-vacancies

abstract:
  For the Sr2-xIrO4 system, recent work pointed out the abnormal electronic and
magnetic properties around the critical point. Here, to understand Sr-vacancy
effect on spin-orbit coupled Mott insulator Sr2IrO4, the electronic structure
and local structure distortion for Sr2-xIrO4 system have been investigated by
x-ray absorption spectroscopy (XAS). By comparing the intensity of white-line
features at the IrL2,3-edge x-ray absorption near-edge spectroscopy (XANES), we
observe a sudden rise of the branching ratio in the vicinity of the critical
point.Further analysis on theIrL3 -edge extended x-ray absorption fine
structure (EXAFS) and calculated data demonstrated that the abrupt enhancement
of the branching ratio is intimately related to the less distorted IrO6
octahedra induced by deep Sr-vacancies, which in turn alters the relatively
strength of the spin-orbit coupling (SOC) and crystal electric field (CEF)that
would dictate the abnormal behavior of electronic and magnetic structure near
the critical point.


title: Thermodynamical String Fragmentation

abstract:
  The observation of heavy-ion-like behaviour in pp collisions at the LHC
suggests that more physics mechanisms are at play than traditionally assumed.
The introduction e.g. of quark-gluon plasma or colour rope formation can
describe several of the observations, but as of yet there is no established
paradigm. In this article we study a few possible modifications to the Pythia
event generator, which describes a wealth of data but fails for a number of
recent observations. Firstly, we present a new model for generating the
transverse momentum of hadrons during the string fragmentation process,
inspired by thermodynamics, where heavier hadrons naturally are suppressed in
rate but obtain a higher average transverse momentum. Secondly, close-packing
of strings is taken into account by making the temperature or string tension
environment-dependent. Thirdly, a simple model for hadron rescattering is
added. The effect of these modifications is studied, individually and taken
together, and compared with data mainly from the LHC. While some improvements
can be noted, it turns out to be nontrivial to obtain effects as big as
required, and further work is called for.


title: Novel Ansatzes and Scalar Quantities in Gravito-Electromagnetism

abstract:
  In this work, we focus on the theory of Gravito-Electromagnetism (GEM) -- the
theory that describes the dynamics of the gravitational field in terms of
quantities met in Electromagnetism -- and we propose two novel forms of metric
perturbations. The first one is a generalisation of the traditional GEM ansatz,
and succeeds in reproducing the whole set of Maxwell's equations even for a
dynamical vector potential A. The second form, the so-called alternative
ansatz, goes beyond that leading to an expression for the Lorentz force that
matches the one of Electromagnetism and is free of additional terms even for a
dynamical scalar potential \Phi. In the context of the linearised theory, we
then search for scalar invariant quantities in analogy to Electromagnetism. We
define three novel, 3rd-rank gravitational tensors, and demonstrate that the
last two can be employed to construct scalar quantities that succeed in giving
results very similar to those found in Electromagnetism. Finally, the gauge
invariance of the linearised gravitational theory is studied, and shown to lead
to the gauge invariance of the GEM fields E and B for a general configuration
of the arbitrary vector involved in the coordinate transformations.


title:
Pseudo steady-state non-Gaussian EPR-steering of massive particles in
  pumped and damped Bose-Hubbard dimers

abstract:
  We propose and analyse a pumped Bose-Hubbard dimer as a source of
continuous-variable Einstein-Podolsky-Rosen (EPR) steering with non-Gaussian
statistics. We use the truncated Wigner representation to calculate third and
fourth order cumulants, finding clear signals of non-Gaussianity. We also
calculate the products of inferred quadrature variances which indicate that
states demonstrating the EPR paradox are present. Our proposed experimental
configuration is extrapolated from current experimental techniques and adds
another possibility to the current toolbox of quantum atom optics.


title:
Analytic p-adic Banach spaces and the fundamental lemma of Colmez and
  Fontaine

abstract:
  This article gives a new proof of the fundamental lemma of the "weakly
admissible implies admissible" theorem of Colmez-Fontaine that describes the
semi-stable p-adic representations. To this end, we introduce the category of
spectral Banach spaces, which are p-adic Banach spaces with a C_p-algebra of
analytic functions, and the subcategory of effective Banach-Colmez spaces. The
fundamental lemma states the surjectivity of certain analytic maps and
describes their kernel. It is proven by an explicit count of solutions of the
equations defining these maps. It is equivalent to the existence of functions
of dimension and height of effective Banach-Colmez spaces.


title: Slope filtration on Banach-Colmez spaces

abstract:
  We give a new proof of the "weakly admissible implies admissible" theorem of
Colmez and Fontaine describing the semi-stable p-adic representations. We study
Banach-Colmez spaces, i.e. p-adic Banach spaces with the extra data of a
C_p-algebra of analytic functions. The "weakly admissible" theorem is then a
result of the existence of dimension and height functions on these objects.
Furthermore, we show that the subcategory of Banach-Colmez spaces corresponding
to crystalline representations is naturally filtered by the positive rationals.


title:
A characterization for Adams-type boundedness of the fractional maximal
  operator on generalized Orlicz-Morrey spaces

abstract:
  In the present paper, we shall give a characterization for weak/strong
Adams-type boundedness of the fractional maximal operator on generalized
Orlicz-Morrey spaces.


title:
Hydrodynamical interaction of mildly relativistic ejecta with an ambient
  medium

abstract:
  Hydrodynamical interaction of spherical ejecta freely expanding at mildly
relativistic speeds into an ambient cold medium is studied in semi-analytical
and numerical ways to investigate how ejecta produced in energetic stellar
explosions dissipate their kinetic energy through the interaction with the
surrounding medium. We especially focus on the case in which the circumstellar
medium is well represented by a steady wind at a constant mass-loss rate having
been ejected from the stellar surface prior to the explosion. As a result of
the hydrodynamical interaction, the ejecta and circumstellar medium are swept
by the reverse and forward shocks, leading to the formation of a geometrically
thin shell. We present a semi-analytical model describing the dynamical
evolution of the shell and compare the results with numerical simulations. The
shell can give rise to bright emission as it gradually becomes transparent to
photons. while it is optically thick. We develop an emission model for the
expected emission from the optically thick shell, in which photons in the shell
gradually diffuse out to the interstellar space. Then, we investigate the
possibility that radiation powered by the hydrodynamical interaction is the
origin of an underluminous class of gamma-ray bursts.


title:
Role of valence changes and nanoscale atomic displacements in BiS2-based
  superconductors

abstract:
  Superconductivity within layered crystal structures has attracted sustained
interest among condensed matter community, primarily due to their exotic
superconducting properties. EuBiS2F is a newly discovered member in the
BiS2-based superconducting family, which shows superconductivity at 0.3 K
without extrinsic doping. With 50 at.% Ce substitution for Eu,
superconductivity is enhanced with Tc increased up to 2.2 K. However, the
mechanisms for the Tc enhancement have not yet been elucidated. In this study,
the Ce-doping effect on the self-electron-doped superconductor EuBiS2F was
investigated by X-ray absorption spectroscopy (XAS). We have established a
relationship between Ce-doping and the Tc enhancement in terms of Eu valence
changes and nanoscale atomic displacements. The new finding sheds light on the
interplay among superconductivity, charge and local structure in BiS2-based
superconductors.


title: ESASky: The whole of space Astronomy at your fingertips

abstract:
  ESASky is a new science-driven discovery portal for all ESA astronomical
missions that gives users worldwide a simplified access to high-level
science-ready products from ESA and other data providers. The tool features a
sky exploration interface and a single/multiple target interface, and it
requires no prior knowledge of specific details of each mission. Users can
explore the sky in multiple wavelengths, quickly see the data available for
their targets, and retrieve the relevant products, with just a few clicks. The
first version of the tool, released in May 2016, provides access to imaging
data and a number of catalogues. Future releases will enable retrieval of
spectroscopic data and will incorporate futures to allow time-domain
exploration and the study of Solar System objects.


title: The classical obstacle problem for nonlinear variational energies

abstract:
  We develop the complete free boundary analysis for solutions to classical
obstacle problems related to nondegenerate nonlinear variational energies. The
key tools are optimal $C^{1,1}$ regularity, which we review more generally for
solutions to variational inequalities driven by nonlinear coercive smooth
vector fields, and the results in \cite{FocGelSp15} concerning the obstacle
problem for quadratic energies with Lipschitz coefficients.
  Furthermore, we highlight similar conclusions for locally coercive vector
fields having in mind applications to the area functional, or more generally to
area-type functionals, as well.


title: Testing PSF Interpolation In Weak Lensing With Real Data

abstract:
  Reconstruction of the point spread function (PSF) is a critical process in
weak lensing measurement. We develop a real-data based and galaxy-oriented
pipeline to compare the performances of various PSF reconstruction schemes.
Making use of a large amount of the CFHTLenS data, the performances of three
classes of interpolating schemes - polynomial, Kriging, and Shepard - are
evaluated. We find that polynomial interpolations with optimal orders and
domains perform the best. We quantify the effect of the residual PSF
reconstruction error on shear recovery in terms of the multiplicative and
additive biases, and their spatial correlations using the shear measurement
method of Zhang et al. (2015). We find that the impact of PSF reconstruction
uncertainty on the shear-shear correlation can be significantly reduced by
cross correlating the shear estimators from different exposures. It takes only
0.2 stars (SNR > 100) per square arcmin on each exposure to reach the best
performance of PSF interpolation, a requirement that is generally satisfied in
the CFHTlenS data.


title: On the embedding of central extensions into wreath products

abstract:
  We find a necessary condition for the embedding of a central extension of a
group $G$ with elementary abelian kernel into the wreath product that
corresponds to a permutation action of $G$. The proof uses purely
group-theoretic methods.


title: Squares with three nonzero digits

abstract:
  We determine all integers $n$ such that $n^2$ has at most three base-$q$
digits for $q \in \{2, 3, 4, 5, 8, 16 \}$. More generally, we show that all
solutions to equations of the shape $$ Y^2 = t^2 + M \cdot q^m + N \cdot q^n,
$$ where $q$ is an odd prime, $n > m > 0$ and $t^2, |M|, N < q$, either arise
from "obvious" polynomial families or satisfy $m \leq 3$. Our arguments rely
upon Pad\'e approximants to the binomial function, considered $q$-adically.


title:
Amplicification of Voltage Controlled Magnetic Anisotropy Effect with
  Negative Capacitance

abstract:
  The high current density required by Magnetic Tunneling Junction (MTJ)
switching driven by Spin Transfer Torque (STT) effect leads to large power
consumption and severe reliability issues therefore hinder the timetable for
STT Magnetic Random Access Memory (STT-MRAM) to mass market. By utilizing
Voltage Controlled Magnetic Anisotropy (VCMA) effect, the MTJ can be switched
by voltage effect and is postulated to achieve ultra-low power (fJ). However,
the VCMA coefficient measured in experiments is far too small for MTJ dimension
below 100 nm. Here in this work, a novel approach for the amplification of VCMA
effect which borrow ideas from negative capacitance is proposed. The
feasibility of the proposal is proved by physical simulation and in-depth
analysis.


title: Generic positivity and applications to hyperbolicity of moduli spaces

abstract:
  The proof of the celebrated Viehweg's hyperbolicity conjecture is a
consequence of two remarkable results: Viehweg and Zuo's existence results for
global pluri-differential forms induced by variation in a family of canonically
po-larised manifolds and Campana and P\v{a}un's vast generalisation of
Miyaoka's generic semipositivity result for non-uniruled varieties to the
context of pairs. The aim of this chapter is an exposition of
Campana-P\v{a}un's generic semipositivity theorem .


title: Characterization of $f$-extremal disks

abstract:
  We show uniqueness for overdetermined elliptic problems defined on
topological disks $\Omega$ with $C^2$ boundary, i.e., positive solutions $u$ to
$\Delta u + f(u)=0$ in $\Omega \subset (M^2,g)$ so that $u = 0$ and
$\frac{\partial u}{\partial \vec\eta} = cte $ along $\partial \Omega$,
$\vec\eta$ the unit outward normal along $\partial\Omega$ under the assumption
of the existence of a candidate family. To do so, we adapt the G\'alvez-Mira
generalized Hopf-type Theorem to the realm of overdetermined elliptic problem.
  When $(M^2,g)$ is the standard sphere $\mathbb S^2$ and $f$ is a $C^1$
function so that $f(x)>0$ and $f(x)\ge x \, f'(x)$ for any $x\in\mathbb R_+^*$,
we construct such candidate family considering rotationally symmetric
solutions. This proves the Berestycki-Caffarelli-Nirenberg conjecture in
$\mathbb S^2$ for this choice of $f$. More precisely, this shows that if $u$ is
a positive solution to $\Delta u + f(u) = 0$ on a topological disk $\Omega
\subset \mathbb S^2$ with $C^2$ boundary so that $u = 0$ and $\frac{\partial
u}{\partial \vec\eta} = cte $ along $\partial \Omega$, then $\Omega$ must be a
geodesic disk and $u$ is rotationally symmetric. In particular, this gives a
positive answer to the Schiffer conjecture D for the first Dirichlet eigenvalue
and classifies simply-connected harmonic domains, also called {\it Serrin
Problem}) in $\mathbb S ^2$.


title: Matrix Semigroup Freeness Problems in $\mathrm{SL}(2,\mathbb{Z})$

abstract:
  In this paper we study decidability and complexity of decision problems on
matrices from the special linear group $\mathrm{SL}(2,\mathbb{Z})$. In
particular, we study the freeness problem: given a finite set of matrices $G$
generating a multiplicative semigroup $S$, decide whether each element of $S$
has at most one factorization over $G$. In other words, is $G$ a code? We show
that the problem of deciding whether a matrix semigroup in
$\mathrm{SL}(2,\mathbb{Z})$ is non-free is NP-hard. Then, we study questions
about the number of factorizations of matrices in the matrix semigroup such as
the finite freeness problem, the recurrent matrix problem, the unique
factorizability problem, etc. Finally, we show that some factorization problems
could be even harder in $\mathrm{SL}(2,\mathbb{Z})$, for example we show that
to decide whether every prime matrix has at most $k$ factorizations is
PSPACE-hard.


title: Neutrinos: Fast & Curious

abstract:
  The Standard Model has been effective way beyond expectations in foreseeing
the result of almost all the experimental tests done up so far. In it,
neutrinos are massless. Nonetheless, in recent years we have collected solid
proofs indicating little but non zero masses for the neutrinos (when contrasted
with those of the charged leptons). These masses permit neutrinos to change
their flavor and oscillate, indeed a unique treat. In these lectures, I discuss
the properties and the amazing potential of neutrinos in and beyond the
Standard Model.


title: Conjectures on counting associative 3-folds in $G_2$-manifolds

abstract:
  There is a strong analogy between compact, torsion-free $G_2$-manifolds
$(X,\varphi,*\varphi)$ and Calabi-Yau 3-folds $(Y,J,g,\omega)$. We can also
generalize $(X,\varphi,*\varphi)$ to 'tamed almost $G_2$-manifolds'
$(X,\varphi,\psi)$, where we compare $\varphi$ with $\omega$ and $\psi$ with
$J$. Associative 3-folds in $X$, a special kind of minimal submanifold, are
analogous to $J$-holomorphic curves in $Y$.
  Several areas of Symplectic Geometry -- Gromov-Witten theory, Quantum
Cohomology, Lagrangian Floer cohomology, Fukaya categories -- are built using
'counts' of moduli spaces of $J$-holomorphic curves in $Y$, but give an answer
depending only on the symplectic manifold $(Y,\omega)$, not on the (almost)
complex structure $J$.
  We investigate whether it may be possible to define interesting invariants of
tamed almost $G_2$-manifolds $(X,\varphi,\psi)$ by 'counting' compact
associative 3-folds $N\subset X$, such that the invariants depend only on
$\varphi$, and are independent of the 4-form $\psi$ used to define associative
3-folds.
  We conjecture that one can define a superpotential $\Phi_\psi:{\mathcal
U}\to\Lambda_{>0}$ 'counting' associative $\mathbb Q$-homology 3-spheres
$N\subset X$ which is deformation-invariant in $\psi$ for $\varphi$ fixed, up
to certain reparametrizations $\Upsilon:{\mathcal U}\to{\mathcal U}$ of the
base ${\mathcal U}=$Hom$(H_3(X;{\mathbb Z}),1+\Lambda_{>0})$, where
$\Lambda_{>0}$ is a Novikov ring. Using this we define a notion of '$G_2$
quantum cohomology'. These ideas may be relevant to String Theory or M-Theory
on $G_2$-manifolds.
  We also discuss Donaldson and Segal's proposal in arXiv:0902.3239, section
6.2, to define invariants 'counting' $G_2$-instantons on tamed almost
$G_2$-manifolds $(X,\varphi,\psi)$, with 'compensation terms' counting weighted
pairs of a $G_2$-instanton and an associative 3-fold, and suggest some
modifications to it.


title: On the number of planar Eulerian orientations

abstract:
  The number of planar Eulerian maps with n edges is well-known to have a
simple expression. But what is the number of planar Eulerian orientations with
n edges? This problem appears to be difficult. To approach it, we define and
count families of subsets and supersets of planar Eulerian orientations,
indexed by an integer k, that converge to the set of all planar Eulerian
orientations as k increases. The generating functions of our subsets can be
characterized by systems of polynomial equations, and are thus algebraic. The
generating functions of our supersets are characterized by polynomial systems
involving divided differences, as often occurs in map enumeration. We prove
that these series are algebraic as well. We obtain in this way lower and upper
bounds on the growth rate of planar Eulerian orientations, which appears to be
around 12.5.


title:
Analysis of Nonstationary Time Series Using Locally Coupled Gaussian
  Processes

abstract:
  The analysis of nonstationary time series is of great importance in many
scientific fields such as physics and neuroscience. In recent years, Gaussian
process regression has attracted substantial attention as a robust and powerful
method for analyzing time series. In this paper, we introduce a new framework
for analyzing nonstationary time series using locally stationary Gaussian
process analysis with parameters that are coupled through a hidden Markov
model. The main advantage of this framework is that arbitrary complex
nonstationary covariance functions can be obtained by combining simpler
stationary building blocks whose hidden parameters can be estimated in
closed-form. We demonstrate the flexibility of the method by analyzing two
examples of synthetic nonstationary signals: oscillations with time varying
frequency and time series with two dynamical states. Finally, we report an
example application on real magnetoencephalographic measurements of brain
activity.


title:
La-doping effect on spin-orbit coupled Sr2IrO4 probed by x-ray
  absorption spectroscopy

abstract:
  Sr2IrO4 was predicted to be an unconventional superconductor upon carrier
doping since it highly resembles the high-temperature cuprates. Here, to
understand carrier doping effect on spin-orbit coupled Mott insulator Sr2IrO4,
the electronic structure and local structure distortion for Sr2-xLaxIrO4 system
have been investigated by x-ray absorption spectroscopy (XAS). By comparing the
intensity of white-line features at the Ir L2,3 absorption edges, we observe
remarkably large branching ratios in La-doped compounds, greater than that of
the parent material Sr2IrO4, suggesting a strong spin-orbit interaction (SOI)
for Sr2IrO4-based system. Moreover, extended x-ray absorption fine structure
(EXAFS) spectra demonstrate more regular IrO6 octahedra, i.e. the weakened
crystal electric field (CEF) versus La-doping. By theoretical calculations, the
synergistic effect of regular IrO6 octahedra and electron doping is
established, which accounts for the transition from a Mott insulator to a
conductive state in Sr2-xLaxIrO4-based system.


title:
Higgs Mass and Muon $g-2$ Anomaly in MSSM with Gauge-Gravity hybrid
  Mediation

abstract:
  In general, we can propose the hybrid supersymmetry breakings and hybrid
mediations in the Supersymmetric Standard Models (SSMs). In this paper, we
study the hybrid mediation for supersymmetry (SUSY) breaking. In particular, we
study how to keep the good properties of gravity mediation, gauge mediation,
and anomaly mediation, while solve their problems simultaneously. As an
example, we consider the anomaly-gravity mediation, where all the
supersymmetric particles (sparticles) obtain the SUSY breaking soft terms from
the traditional gravity mediation while gauge mediation gives dominant
contributions to the soft terms in the colored sector due to the splitted
messengers. Thus, we can realize the electroweak supersymmetry naturally where
the sleptons, sneutrinos, and electroweakinos are light within one TeV while
the squarks and gluino are heavy around a few TeVs. And then we can explain 125
GeV Higgs mass, satisfy the LHC SUSY search bounds, and explain the anomalous
magnetic momement of muon, etc. Moreover, the gluino and squarks are well
beyond the current LHC Run II searches.


title: Exploring inside-out Doppler tomography: magnetic cataclysmic variables

abstract:
  We present the results of applying our inside-out velocity projection and
flux modulation mapping techniques to the Doppler tomography of magnetic
cataclysmic variables. The inside-out tomogram is constructed by directly
projecting phase-resolved spectra onto the inside-out framework. In addition,
our flux modulation mapping technique extracts any information related to the
modulation of the line flux by utilising consecutive half-phase tomograms. We
apply this to both the standard and the inside-out techniques. Our test cases,
the polars HU Aqr and V834 Cen, and the intermediate polar PQ Gem, were chosen
because of their known accretion characteristics, namely ballistic, magnetic
and curtain dominated accretion, respectively. In all three cases the
inside-out tomogram better exposes low-velocity emission details which are
overly compacted in the standard tomogram. This is especially apparent for the
mid-inclination V834 Cen where the almost blob-like blended lower velocity
emission in the standard tomogram is more exposed in the inside-out tomogram,
making it easier to distinguish between the ballistic and magnetically confined
accretion flows that are evident in the trailed spectra. Similarly, the
inside-out tomogram enhances high velocity emission details which are washed
out in the standard tomogram. This is particularly effective in revealing the
high velocity magnetic accretion flows in the polars HU Aqr and V834 Cen. The
addition of our flux modulation technique gives a significant improvement in
reproducing the trailed input spectra adding more confidence to the
interpretation of the Doppler maps. Furthermore, amplitude and phase maps are
constructed that further reveal amplitude and phasing characteristics of the
emission components in the three test cases.


title:
Anisotropic Dielectric Breakdown Strength of Single Crystal Hexagonal
  Boron Nitride

abstract:
  Dielectric breakdown has historically been of great interest from the
perspectives of fundamental physics and electrical reliability. However, to
date, the anisotropy in the dielectric breakdown has not been discussed. Here,
we report an anisotropic dielectric breakdown strength (EBD) for h-BN, which is
used as an ideal substrate for two-dimensional (2D) material devices. Under a
well-controlled relative humidity, EBD values in the directions both normal and
parallel to the c axis (EBD+c & EBD//c) were measured to be 3 and 12 MV/cm,
respectively. When the crystal structure is changed from sp3 of cubic-BN (c-BN)
to sp2 of h-BN, EBD+c for h-BN becomes smaller than that for c-BN, while EBD//c
for h-BN drastically increases. Therefore, h-BN can possess a relatively high
EBD concentrated only in the direction parallel to the c axis by conceding a
weak bonding direction in the highly anisotropic crystal structure. This
explains why the EBD//c for h-BN is higher than that for diamond. Moreover, the
presented EBD value obtained from the high quality bulk h-BN crystal can be
regarded as the standard for qualifying the crystallinity of h-BN layers grown
via chemical vapor deposition for future electronic applications.


title:
Panchromatic Spectral Energy Distributions of simulated galaxies:
  results at redshift $z=0$

abstract:
  We present predictions of Spectral Energy Distributions (SEDs), from the UV
to the FIR, of simulated galaxies at $z=0$. These were obtained by
post-processing the results of an N-body+hydro simulation of a small
cosmological volume, that uses the Multi-Phase Particle Integrator (MUPPI) for
star formation and stellar feedback, with the GRASIL-3D radiative transfer
code, that includes reprocessing of UV light by dust. Physical properties of
galaxies resemble observed ones, though with some tension at small and large
stellar masses. Comparing predicted SEDs of simulated galaxies with different
samples of local galaxies, we find that these resemble observed ones, when
normalised at 3.6 $\mu$m. A comparison with the Herschel Reference Survey shows
that, when binning galaxies in Star Formation Rate (SFR), average SEDs are
reproduced to within a factor of $\sim2$ even in normalization, while binning
in stellar mass highlights the same tension that is present in the stellar mass
-- SFR plane. We use our sample to investigate the correlation of IR luminosity
in Spitzer and Herschel bands with several galaxy properties. SFR is the
quantity that best correlates with IR light up to $160\ \mu$m, while at longer
wavelengths better correlations are found with molecular mass and, at $500\
\mu$m, with dust mass. However, using the position of the FIR peak as a proxy
for cold dust temperature, we assess that heating of cold dust is mostly
determined by SFR, with stellar mass giving only a minor contribution. We
finally show how our sample of simulated galaxies can be used as a guide to
understand the physical properties and selection biases of observed samples.


title: A note on graviton exchange in emergent gravity scenario

abstract:
  It is well-known that there exists a close relation between a large $N$
matrix model and noncommutative (NC) field theory: The latter can be naturally
obtained from the former by expanding it around a specific background. Because
the matrix model can be a constructive formulation of string theory, this
relation suggests that NC field theory can also include quantum gravity. In
particular, the NC $U(1)$ gauge theory attracts much attention because its
low-energy effective action partially contains gravity where the metric is
determined by the $U(1)$ gauge field. Thus, the NC $U(1)$ gauge theory could be
a quantum theory of gravity. In this paper, we investigate the scenario by
calculating the scattering amplitude of massless test particles, and find that
the NC $U(1)$ gauge theory correctly reproduces the amplitude of the usual
graviton exchange if the noncommutativity that corresponds to the background of
the matrix model is appropriately averaged. Although this result partially
supports the relation between the NC $U(1)$ gauge theory and gravity, it is
desirable to find a mechanism by which such an average is naturally realized.


title: Topological transitions in Ising models

abstract:
  The thermal dynamics of the two-dimensional Ising model and quantum dynamics
of the one-dimensional transverse-field Ising model (TFIM) are mapped to one
another through the transfer-matrix formalism. We show that the fermionised
TFIM undergoes a Fermi-surface topology-changing Lifshitz transition at its
critical point. We identify the degree of freedom which tracks the Lifshitz
transition via changes in topological quantum numbers (e.g., Chern number,
Berry phase etc.). An emergent $SU(2)$ symmetry at criticality is observed to
lead to a topological quantum number different from that which characterises
the ordered phase. The topological transition is also understood via a spectral
flow thought-experiment in a Thouless charge pump, revealing the bulk-boundary
correspondence across the transition. The duality property of the phases and
their entanglement content are studied, revealing a holographic relation with
the entanglement at criticality. The effects of a non-zero longitudinal field
and interactions that scatter across the singular Fermi surface are treated
within the renormalisation group (RG) formalism. The analysis reveals that the
critical point of the 1D TFIM and the 1D spin-1/2 Heisenberg chain are
connected via a line of $SU(2)$-symmetric theories. We extend our analysis to
show that the classical to quantum correspondence links the critical theories
of Ising models in various dimensions holographically through the universal
effective Hamiltonian that describes the Lifshitz transition of the 1D TFIM. We
obtain in this way a unified perspective of transitions in Ising models that
lie beyond the traditional Ginzburg-Landau-Wilson paradigm. We discuss the
consequences of our results for similar topological transitions observed in
classical spin models, topological insulators, superconductors and lattice
gauge-field theories which are related to the Ising universality class.

categories: cond-mat.stat-mech cond-mat.other cond-mat.supr-con hep-lat


title:
Classification of Kerr-de Sitter-like spacetimes with conformally flat
  Scri

abstract:
  We provide a classification of $\Lambda>0$-vacuum spacetimes which admit a
Killing vector field with respect to which the associated "Mars-Simon tensor"
(MST) vanishes and having a conformally flat $\mathcal{J}^-$ (or
$\mathcal{J}^+$). To that end, we also give a complete classification of
conformal Killing vector fields on the $3$-sphere $\mathbb{S}^3$ up to M\"obius
transformations shedding light on the two fundamental constants that
characterize the family of Kerr-de Sitter-like spacetimes, which turn out to be
well-defined geometrical invariants. The topology of $\mathcal{J}$ is
determined in every case, and a characterization result at $\mathcal{J}$ of the
Kerr-de Sitter family presented.


title:
Representing regular pseudocomplemented Kleene algebras by
  tolerance-based rough sets

abstract:
  We show that any regular pseudocomplemented Kleene algebra defined on an
algebraic lattice is isomorphic to a rough set Kleene algebra determined by a
tolerance induced by an irredundant covering.


title: Quantum hydrodynamics in the rotating reference frame

abstract:
  In this paper we apply quantum hydrodynamics (QHD) to study the quantum
evolution of a system of spinning particles and particles that have the
electric dipole moments EDM in the rotating reference frame. The method
presented is based on the many-particle microscopic Schrodinger equation in the
rotating reference frame. Fundamental QHD equations for charged or neutral
spinning and EDM-bearing particles were shaped due to this method and contain
the spin-dependent inertial force field. The polarization dynamics in systems
of neutral particles in the rotating frame is shown to cause formation of a new
type of waves, the dipole-inertial waves. We have analyzed elementary
excitations in a system of neutral polarized fluids placed into an external
electric field in 2D and 3D cases. We predict the novel type of 2D
dipole-inertial wave and 3D - polarization wave modified by rotation in systems
of particles with dipole-dipole interactions.


title:
Massive Machine-Type Communication (mMTC) Access with Integrated
  Authentication

abstract:
  We present a connection establishment protocol with integrated
authentication, suited for Massive Machine-Type Communications (mMTC). The
protocol is contention-based and its main feature is that a device contends
with a unique signature that also enables the authentication of the device
towards the network. The signatures are inspired by Bloom filters and are
created based on the output of the MILENAGE authentication and encryption
algorithm set, which is used in the authentication and security procedures in
the LTE protocol family. We show that our method utilizes the system resources
more efficiently, achieves lower latency of connection establishment for
Poisson arrivals and allows a $87\%$ signalling overhead reduction. An
important conclusion is that the mMTC traffic benefits profoundly from
integration of security features into the connection establishment/access
protocols, instead of addressing them post-hoc, which has been a common
practice.


title:
Weighted sub-Laplacians on M\'etivier Groups: Essential Self-Adjointness
  and Spectrum

abstract:
  Let $G$ be a M\'etivier group and let $N$ be any homogeneous norm on $G$. For
$\alpha>0$ denote by $w_\alpha$ the function $e^{-N^\alpha}$ and consider the
weighted sub-Laplacian $\mathcal{L}^{w_\alpha}$ associated with the Dirichlet
form $\phi \mapsto \int_{G} |\nabla_\mathcal{H}\phi(y)|^2 w_\alpha(y)\, dy$,
where $\nabla_\mathcal{H}$ is the horizontal gradient on $G$. Consider
$\mathcal{L}^{w_\alpha}$ with domain $C_c^\infty$. We prove that
$\mathcal{L}^{w_\alpha}$ is essentially self-adjoint when $\alpha \geq 1$. For
a particular $N$, which is the norm appearing in $\mathcal{L}$'s fundamental
solution when $G$ is an H-type group, we prove that $\mathcal{L}^{w_\alpha}$
has purely discrete spectrum if and only if $\alpha>2$, thus proving a
conjecture of J. Inglis.


title:
Rank-one actions, their $(C,F)$-models and constructions with bounded
  parameters

abstract:
  Let $G$ be a discrete countable infinite group. We show that each topological
$(C,F)$-action $T$ of $G$ on a locally compact non-compact Cantor set is a free
minimal amenable action admitting a unique up to scaling non-zero invariant
Radon measure (answer to a question by Kellerhals, Monod and R{\o}rdam). We
find necessary and sufficient conditions under which two such actions are
topologically conjugate in terms of the underlying $(C,F)$-parameters. If $G$
is linearly ordered Abelian then the topological centralizer of $T$ is trivial.
If $G$ is monotileable and amenable, denote by ${\cal A}_G$ the set of all
probability preserving actions of $G$ on the unit interval with Lebesgue
measure and endow it with the natural topology. We show that the set of
$(C,F)$-parameters of all $(C,F)$-actions of $G$ furnished with a suitable
topology is a model for ${\cal A}_G$ in the sense of Forman, Rudolph and Weiss.
If $T$ is a rank-one transformation with bounded sequences of cuts and spacer
maps then we found simple necessary and sufficient conditions on the related
$(C,F)$-parameters under which (i) $T$ is rigid, (ii) $T$ is totally ergodic.
It is found an alternative proof of Ryzhikov's theorem that if $T$ is totally
ergodic and non-rigid rank-one map with bounded parameters then $T$ has MSJ. We
also give a more general version of the criterium (by Gao and Hill) for
isomorphism and disjointness of two commensurate non-rigid totally ergodic
rank-one maps with bounded parameters. It is shown that the rank-one
transformations with bounded parameters and no spacers over the last subtowers
is a proper subclass of the rank-one transformations with bounded parameters.


title:
Physical effects involved in the measurements of neutrino masses with
  future cosmological data

abstract:
  Future Cosmic Microwave Background experiments together with upcoming galaxy
and 21-cm surveys will provide extremely accurate measurements of different
cosmological observables located at different epochs of the cosmic history. The
new data will be able to constrain the neutrino mass sum with the best
precision ever. In order to exploit the complementarity of the different
redshift probes, a deep understanding of the physical effects driving the
impact of massive neutrinos on CMB and large scale structures is required. The
goal of this work is to describe these effects, assuming a summed neutrino mass
close to its minimum allowed value. We find that parameter degeneracies can be
removed by appropriate combinations, leading to robust and model independent
constraints. A joint forecast of the sensitivity of Euclid and DESI surveys
together with a CORE-like CMB experiment leads to a $1\sigma$ uncertainty of
$14$~meV on the summed neutrino mass. However this particular combination gives
rise to a peculiar degeneracy between $M_\nu$ and the optical depth at
reionization. Independent constraints from 21-cm surveys can break this
degeneracy and decrease the $1\sigma$ uncertainty down to $12$~meV.


title: Delayed versus accelerated quarkonium formation in a magnetic field

abstract:
  Formation time of heavy quarkonia in a homogeneous magnetic field is analyzed
by using a phenomenological ansatz of the vector current correlator. Because
the existence of a magnetic field mixes vector quarkonia ($J/\psi$,
$\psi^\prime$) and their pseudoscalar partners ($\eta_c$, $\eta_c^\prime$), the
properties of the quarkonia can be modified through such a spin mixing. This
means that the formation time of quarkonia is also changed by the magnetic
field. We show the formation time of vector quarkonia is delayed by an
idealized constant magnetic field, where the formation time of the excited
state becomes longer than that of the ground state. As a more realistic
situation in heavy-ion collisions, effects by a time-dependent magnetic field
are also discussed, where delayed formation of $J/\psi$ and $\psi^\prime$ and
very early formation of $\eta_c$ and $\eta_c^\prime$ are found.


title: Multi-indexed Meixner and Little $q$-Jacobi (Laguerre) Polynomials

abstract:
  As the fourth stage of the project multi-indexed orthogonal polynomials, we
present the multi-indexed Meixner and little $q$-Jacobi (Laguerre) polynomials
in the framework of `discrete quantum mechanics' with real shifts defined on
the semi-infinite lattice in one dimension. They are obtained, in a similar way
to the multi-indexed Laguerre and Jacobi polynomials reported earlier, from the
quantum mechanical systems corresponding to the original orthogonal polynomials
by multiple application of the discrete analogue of the Darboux transformations
or the Crum-Krein-Adler deletion of virtual state vectors. The virtual state
vectors are the solutions of the matrix Schr\"odinger equation on all the
lattice points having negative energies and infinite norm. This is in good
contrast to the ($q$-)Racah systems defined on a finite lattice, in which the
`virtual state' vectors satisfy the matrix Schr\"odinger equation except for
one of the two boundary points.


title:
Competing order in the fermionic Hubbard model on the hexagonal graphene
  lattice

abstract:
  We study the phase diagram of the fermionic Hubbard model on the hexagonal
lattice in the space of on-site and nearest neighbor couplings with
Hybrid-Monte-Carlo simulations. With pure on-site repulsion this allows to
determine the critical coupling strength for spin-density wave formation with
the standard approach of introducing a small mass term, explicitly breaking the
sublattice symmetry. The analogous mass term for charge-density wave formation
above a critical nearest-neighbor repulsion, on the other hand, would introduce
a fermion sign problem. The competition between the two and the phase diagram
in the space of the two coouplings can however be studied in simulations
without explicit sublattice symmetry breaking. Our results compare
qualitatively well with the Hartree-Fock phase diagram. We furthermore
demonstrate how spin-symmetry breaking by the Euclidean time discretization can
be avoided also, when using an improved fermion action based on an exponetial
transfer matrix with exact sublattice symmetry.


title: Density-of-states

abstract:
  Although Monte Carlo calculations using Importance Sampling have matured into
the most widely employed method for determining first principle results in QCD,
they spectacularly fail for theories with a sign problem or for which certain
rare configurations play an important role. Non-Markovian Random walks, based
upon iterative refinements of the density-of-states, overcome such overlap
problems. I will review the Linear Logarithmic Relaxation (LLR) method and, in
particular, focus onto ergodicity and exponential error suppression.
Applications include the high-state Potts model, SU(2) and SU(3) Yang-Mills
theories as well as a quantum field theory with a strong sign problem: QCD at
finite densities of heavy quarks.


title:
Buffer Layer Engineering on Graphene via Various Oxidation Methods for
  Atomic Layer Deposition

abstract:
  The integration of high-k oxide on graphene using atomic layer deposition
requires an electrically reliable buffer layer. In this study, Y was selected
as the buffer layer due to the highest oxidation ability in rare earth elements
and various oxidation methods (atmospheric, high-pressure O2 and ozone) were
applied to the Y metal buffer layer. By optimizing oxidation conditions of the
top gate insulator, we successfully improve the capacitance of top gate Y2O3
insulator and demonstrate a large Ion/Ioff ratio for bilayer graphene under an
external electric field.


title:
Implications of Efimov physics for the description of three and four
  nucleons in chiral effective field theory

abstract:
  In chiral effective field theory the leading order (LO) nucleon-nucleon
potential includes two contact terms, in the two spin channels $S=0,1$, and the
one-pion-exchange potential. When the pion degrees of freedom are integrated
out, as in the pionless effective field theory, the LO potential includes two
contact terms only. In the three-nucleon system, the pionless theory includes a
three-nucleon contact term interaction at LO whereas the chiral effective
theory does not. Accordingly arbitrary differences could be observed in the LO
description of three- and four-nucleon binding energies. We analyze the two
theories at LO and conclude that a three-nucleon contact term is necessary at
this order in both theories. In turn this implies that subleading three-nucleon
contact terms should be promoted to lower orders. Furthermore this analysis
shows that one single low energy constant might be sufficient to explain the
large values of the singlet and triplet scattering lengths.


title:
Quasi-periodic solutions for perturbed generalized nonlinear vibrating
  string equation with singularities

abstract:
  {\bf Abstract}: The existence of 2-dimensional KAM tori is proved for the
perturbed generalized nonlinear vibrating string equation with singularities
$u_{tt}=((1-x^2)u_x)_x-mu-u^3$ subject to certain boundary conditions by means
of infinite-dimensional KAM theory with the help of partial Birkhoff normal
form, the characterization of the singular function space and the estimate of
the integrals related to Legendre basis.


title: The key role of solar dynamics in the chromospheric Hanle polarization

abstract:
  The quantum theory of polarized light allows one to model scattering in the
solar atmosphere for inferring its properties. This powerful approach has
revealed two key long-standing problems in solar physics: the puzzling dilemmas
between theory and observations in several anomalously polarized spectral lines
and the need for inferring the ubiquitous weak chromospheric magnetic fields,
which requires discriminating the Hanle effect in dynamic optically thick
plasmas. However, the ever-present dynamics, i.e., the temporal evolution of
heatings and macroscopic motions, has been widely disregarded when modeling and
interpreting the scattering polarization. This has hindered a consistent
theoretical solution to the puzzle while falsifying the Hanle diagnosis. Here,
we show that the dynamical evolution is a keystone for solving both problems
because its systematic impact allows an explanation of the observations from
'anomalous' instantaneous polarization signals. Evolution accounted for, we
reproduce amplitudes and (spectral and spatial) shapes of the Ca I 4227 A
polarization at solar disk center, identifying a restrictive arrangement of
magnetic fields, kinematics, heatings, and spatio-temporal resolution. We find
that the joint action of dynamics, Hanle effect, and low temporal resolutions
mimics Zeeman linear polarization profiles, the true weak-field Zeeman signals
being negligible. Our results allow reinterpretation of many polarization
signals of the solar spectra and support time-dependent scattering polarization
as a powerful tool for deciphering the spatio-temporal distribution of
chromospheric heatings and fields. This approach may be a key aid in developing
the Hanle diagnosis for the solar atmosphere.


title: The D$_1$ enigma and its physical origin

abstract:
  The D$_1$ enigma is an anomaly, which was first observed on the Sun as a
symmetric polarization peak centered in the core of the sodium D$_1$ line that
is expected to be intrinsically unpolarizable. To resolve this problem the
underlying physics was later explored in the laboratory for D$_1$ scattering at
potassium vapor. The experiment showed that the scattering phase matrix element
$P_{21}$ is positive while $P_{22}$ is negative, although standard quantum
scattering theory predicts that both should be zero. This experimental
contradiction is currently the main manifestation of the D$_1$ enigma.
Subsequent theoretical studies showed that such polarization effects may arise
if scattering theory is extended to allow for interference effects due to level
splittings of the ground state, in contrast to standard scattering theory,
which only allows for interferences from level splittings of the intermediate
state. Previous attempts to implement this idea had to rely on heuristic
arguments to allow modeling of the experimental data. In the present paper we
develop a formulation of the theory that can be self-consistently applied to
quantum systems with any combination of electronic and nuclear spins. No
statistical equilibrium or optical pumping is needed. The atom is assumed to be
unpolarized at the beginning of each scattering event. The theory is capable of
explaining both the phase matrix behavior of the laboratory data and the
existence of a symmetric polarization peak in the core of the solar D$_1$ line.
We also use it to predict the polarization structures that we expect to see in
a next-generation laboratory experiment with the rubidium isotopes $^{87}$Rb
and $^{85}$Rb.


title:
Purity Calculation Method for Events Samples with Two Identical
  Particles

abstract:
  This paper studies a method of a two dimensional background calculation for
an analysis of events with two particles of the same type registered in
experiments in high-energy physics. The standard two-dimensional integration is
replaced by an approximation of a specially constructed one-dimensional
function. The number of the signal events is found by the subtraction of the
background events. It allows calculating the purity of the selection. The
procedure does not require a hypothesis about background and signal shapes.
Monte Carlo examples of double J/psi samples are used to demonstrate high
performance of the purity calculation method. A comparison of the method with
standard two-dimensional fit of the signal revealed a systematic shift of the
fit results to lower values.


title: The divisible sandpile with heavy-tailed variables

abstract:
  This work deals with the divisible sandpile model when an initial
configuration sampled from a heavy-tailed distribution. Extending results of
Levine et al. (2015) and Cipriani et al. (2016) we determine sufficient
conditions for stabilization and non-stabilization on infinite graphs. We
determine furthermore that the scaling limit of the odometer on the torus is an
$\alpha$-stable random distribution.


title: The information recovery problem

abstract:
  The issue of unitary evolution during creation and evaporation of a black
hole remains controversial. We~argue that some prominent cures are more
troubling than the disease, demonstrate that their central element---forming of
the event horizon before the evaporation begins---is not necessarily true, and
describe a fully coupled matter-gravity system which is manifestly unitary.


title: On the Dirac-Frenkel Variational Principle on Tensor Banach Spaces

abstract:
  The main goal of this paper is to extend the so-called Dirac-Frenkel
Variational Principle in the framework of tensor Banach spaces. To this end we
observe that a tensor product of normed spaces can be described as a union of
disjoint connected components. Then we show that each of these connected
components, composed by tensors in Tucker format with a fixed rank, is a Banach
manifold modelled in a particular Banach space, for which we provide local
charts. The description of the local charts of these manifolds is crucial for
an algorithmic treatment of high-dimensional partial differential equations and
minimization problems. In order to describe the relationship between these
manifolds and the natural ambient space we prove under natural conditions that
each connected component can be immersed in a particular ambient Banach space.
This fact allows us to finally extend the Dirac-Frenkel variational principle
in the framework of topological tensor spaces.


title:
Major Maintenance Schedule Optimization for Electric Multiple Unit
  Considering Passenger Transport Demand

abstract:
  It is an important objective pursued in a railway agency or company to reduce
the major maintenance costs of electric multiple unit (EMU). The EMU major
maintenance schedule decides when to undergo major maintenance or undertake
transportation task for train-set, based on practical requirements, such as
passenger transport demand, workshop inspection capacity, and maintenance
requirements. Experienced railway practitioners can generally produce a
feasible major maintenance schedule; however, this manual process is
time-consuming, and an optimal solution is not guaranteed. This research
constructs a time-space network that can display the train-set status
transformation process between available and major maintenance status. On this
basis, a 0-1 integer programming model is developed to reduce the major
maintenance costs with consideration of all necessary regulations and practical
constraints. Compared with the manual process, the genetic algorithm with
simulated annealing survival mechanism is also developed to improve solution
quality and efficiency. It can reduce the complexity of the algorithm
substantially by excluding infeasible solutions when constructing the model.


title: The Regularity of Conformal Target Harmonic Maps

abstract:
  In a recent paper the author introduced a new method based on viscosity
techniques for producing minimal surfaces by minmax arguments. The present work
corresponds to the regularity part of the method. Precisely we establish that
any weakly conformal $W^{1,2}$ map from a riemann surface $S$ into a closed
oriented sub-manifold $N^n$ of an euclidian space ${\mathbb R}^m$ realizes a
stationary varifold if and only if it is a smooth conformal harmonic map form
$S$ into $N^n$.


title: On ranks of regular polygons

abstract:
  In this paper we study various versions of extension complexity for polygons
through the study of factorization ranks of their slack matrices. In
particular, we develop a new asymptotic lower bound for their nonnegative rank,
shortening the gap between the current bounds, we introduce a new upper bound
for their boolean rank, deriving from it some new numerical results, and we
study their complex semidefinite rank, uncovering the possibility of non
monotonicity of the ranks of regular $n$-gons.


title:
Bimodal Distribution of Galactic Disk Stars on the [alpha/Fe]-[Fe/H]
  Plane as a Possible Evidence of Discontinuous Radial Migration History

abstract:
  We investigate the role of radial migration history of stars in chemical
evolution of a disk galaxy, in particular in understanding the origin of their
bimodal distribution on the [alpha/Fe]-[Fe/H] plane. For this purpose, we
examine the three different models with no, continuous, and discontinuous
radial migration, respectively. We find that for the model with radial
migration, the [alpha/Fe] ratios of stars in outer disk regions decrease more
rapidly with time than the model without radial migration, because the
associated net transfer of intermediate and old disk stars from inner to outer
disk regions increases the rate of Type Ia relative to that of Type II
supernovae in the latter regions. Moreover, in the model assuming rapid and
discontinuous radial migration, its effect on the stellar abundances at larger
radii is significant enough to provide the large difference in the evolution of
stars on the [alpha/Fe]-[Fe/H] plane between inner and outer disk regions. As a
result we obtain the bimodal distribution of disk stars on the
[alpha/Fe]-[Fe/H] plane as observed in the Galactic stellar disk, thereby
implying that the event of discontinuous radial migration may play a key role
in reproducing the observed bimodality of stars on this abundance-ratio
diagram. We discuss possible mechanisms causing such discontinuous radial
migration in the early evolution of the Galactic disk, including the event of
minor merging of a relatively massive satellite onto the stellar disk.


title: Extremal product-one free sequences in $C_q \rtimes_s C_m$

abstract:
  Let $G$ be a finite group, written multiplicatively. The Davenport constant
of $G$ is the smallest positive integer $d$ such that every sequence of $G$
with $d$ elements has a non-empty subsequence with product $1$. Let $C_n \simeq
\mathbb Z_n$ be the cyclic group of order $n$. Bass (2007) showed that the
Davenport constant of the metacyclic group $C_q \rtimes_s C_m$, where $q$ is a
prime number and $\text{ord}_q(s) = m \ge 2$, is $m+q-1$. In this paper, we
explicit the form of all sequences $S$ of $C_q \rtimes_s C_m$, with $q+m-2$
elements, that are free of product-$1$ subsequences.


title: Primary spectrum of $\mathcal{C}^\infty(M)$ and jets theory

abstract:
  We consider, for each smooth manifold $M$, the set $\mathbb{M}$ comprised by
all the primary ideals of $\mathcal{C}^\infty(M)$ which are closed and whose
radical is maximal. The classical Lie theory of jets (jets of submanifolds)
must be extended to $\mathbb{M}$ in order to have nice functorial properties.
We will begin with the purely algebraic notions, referred always to the ring
$\mathcal{C}^\infty(M)$. Subsequently it will be introduced the differentiable
structures on each jets space of a given type. The theory of contact systems,
which generalizes the classical one, has a part purely algebraic and another
one which depends on the differentiable structures.


title:
Microscopic statistical description of incompressible Navier-Stokes
  granular fluids

abstract:
  Based on the recently-established Master kinetic equation and related Master
constant H-theorem which describe the statistical behavior of the
Boltzmann-Sinai classical dynamical system for smooth and hard spherical
particles, the problem is posed of determining a microscopic statistical
description holding for an incompressible Navier-Stokes fluid. The goal is
reached by introducing a suitable mean-field interaction in the Master kinetic
equation. The resulting Modified Master Kinetic Equation (MMKE) is proved to
warrant at the same time the condition of mass-density incompressibility and
the validity of the Navier-Stokes fluid equation. In addition, it is shown that
the conservation of the Boltzmann-Shannon entropy can similarly be warranted.
Applications to the plane Couette and Poiseuille flows are considered showing
that they can be regarded as final decaying states for suitable non-stationary
flows. As a result, it is shown that an arbitrary initial stochastic $1-$body
PDF evolving in time by means of MMKE necessarily exhibits the phenomenon of
Decay to Kinetic Equilibrium (DKE), whereby the $1-$body PDF asymptotically
relaxes to a stationary and spatially-uniform Maxwellian PDF.


title: The mid-IR water and silicate relation in protoplanetary disks

abstract:
  Mid-IR water lines from protoplanetary disks around T Tauri stars have a
detection rate of 50\%. Models have identified multiple physical properties of
disks such as dust-to-gas mass ratio, dust size power law distribution, disk
gas mass, disk inner radius, and disk scale height as potential explanation for
the current detection rate. We search for a connection between mid-IR water
line fluxes and the strength of the 10~$\mu$m silicate feature. We analyse
observed water line fluxes from three blends and compute the 10~$\mu$m silicate
feature strength from Spitzer spectra. We use a series of published models,
exploring disk dust and gas properties, and the effects of different stars. The
models also show that the increasing stellar luminosity enhance simultaneously
the strength of this dust feature and the water lines fluxes. No correlation is
found between the observed mid-IR water lines and the 10~$\mu$m silicate. Our
sample shows the same difference in the peak strength between amorphous and
crystalline silicates that was noted in earlier studies, but our models do not
support this intrinsic difference in silicate peak strength. Individual
properties of our model series are not able to reproduce the most extreme
observations, suggesting that more complex dust properties are required. A
parametrized settling prescription is able to boost the peak strength by a
factor 2 for the standard model. Water line fluxes are unrelated to the
composition of the dust. The pronounced regular trends seen in the model
results are washed out in the data due to the larger diversity in stellar and
disk properties compared to our model series. The disks with with weaker mid-IR
water line fluxes are depleted in gas or enhanced in dust in the inner 10~au.
In the case of gas depleted disks, settling produces very strong 10~$\mu$m
silicate features, with strong peak strength.


title: Anisotropic mesh adaptation in Firedrake with PETSc DMPlex

abstract:
  Despite decades of research in this area, mesh adaptation capabilities are
still rarely found in numerical simulation software. We postulate that the
primary reason for this is lack of usability. Integrating mesh adaptation into
existing software is difficult as non-trivial operators, such as error metrics
and interpolation operators, are required, and integrating available adaptive
remeshers is not straightforward. Our approach presented here is to first
integrate Pragmatic, an anisotropic mesh adaptation library, into DMPlex, a
PETSc object that manages unstructured meshes and their interactions with
PETSc's solvers and I/O routines. As PETSc is already widely used, this will
make anisotropic mesh adaptation available to a much larger community. As a
demonstration of this we describe the integration of anisotropic mesh
adaptation into Firedrake, an automated Finite Element based system for the
portable solution of partial differential equations which already uses PETSc
solvers and I/O via DMPlex. We present a proof of concept of this integration
with a three-dimensional advection test case.


title:
Loading Pricing of Catastrophe Bonds and Other Long-Dated,
  Insurance-Type Contracts

abstract:
  Catastrophe risk is a major threat faced by individuals, companies, and
entire economies. Catastrophe (CAT) bonds have emerged as a method to offset
this risk and a corresponding literature has developed that attempts to provide
a market-consistent pricing methodology for these and other long-dated,
insurance-type contracts. This paper aims to unify and generalize several of
the widely-used pricing approaches for long-dated contracts with a focus on
stylized CAT bonds and market-consistent valuation. It proposes a loading
pricing concept that combines the theoretically possible minimal price of a
contract with its formally obtained risk neutral price, without creating
economically meaningful arbitrage. A loading degree controls how much influence
the formally obtained risk neutral price has on the market price. A key finding
is that this loading degree has to be constant for a minimally fluctuating
contract, and is an important, measurable characteristic for prices of
long-dated contracts. Loading pricing allows long-dated, insurance-type
contracts to be priced less expensively and with higher return on investment
than under classical pricing approaches. Loading pricing enables insurance
companies to accumulate systematically reserves needed to manage its risk of
ruin in a market consistent manner.


title: Van der Waals force assisted heat transfer for vacuum gap spacings

abstract:
  Phonons (collective atomic vibrations in solids) are more effective in
transporting heat than photons. This is the reason why the conduction mode of
heat transport in nonmetals (mediated by phonons) is dominant compared to the
radiation mode of heat transport (mediated by photons). However, since phonons
are unable to traverse a vacuum gap (unlike photons) it is commonly believed
that two bodies separated by a gap cannot exchange heat via phonons. Recently,
a mechanism was proposed by which phonons can transport heat across a vacuum
gap - through Van der Waals interaction between two bodies with gap less than
wavelength of light. Such heat transfer mechanisms are highly relevant for
heating (and cooling) of nanostructures; the heating of the flying heads in
magnetic storage disks is a case in point. Here, the theoretical derivation for
modeling phonon transmission is revisited and extended to the case of two
bodies made of different materials separated by a vacuum gap. Magnitudes of
phonon transmission, and hence the heat transfer, for commonly used materials
in the micro and nano-electromechanical industry are calculated and compared
with the calculation of conduction heat transfer through air for small gaps.


title:
Joint Transceiver and Power Splitter Design Over Two-Way Relaying
  Channel with Lattice Codes and Energy Harvesting

abstract:
  This letter considers a compute-and-forward two-way relaying channel with
simultaneous wireless information and power transfer. Specifically, two
single-antenna users exchange information via a multi-antenna relay station
based on nested lattice codes. Meanwhile, wireless energies flow from the relay
to users for circuit consumption and uplink transmission. Based on this model,
an optimization problem is formulated to minimize the transmit power at relay,
while guaranteeing the minimal transmission rate at each user. To solve the
problem, we propose an efficient iterative algorithm to jointly optimize the
transmitter, receiver and power splitter, based on semi-definite relaxation and
semi-definite programming. Numerical results of relay transmission powers
validate our analysis.


title:
Blinded sample size re-estimation in three-arm trials with 'gold
  standard' design

abstract:
  The sample size of a clinical trial relies on information about nuisance
parameters such as the outcome variance. When no or only limited information is
available, it has been proposed to include an internal pilot study in the
design of the trial. Based on the results of the internal pilot study, the
initially planned sample size can be adjusted. In this paper, we study blinded
sample size re-estimation in the 'gold standard' design for normally
distributed outcomes. The 'gold standard' design is a three-arm clinical trial
design which includes an active and a placebo control in addition to an
experimental treatment. We compare several sample size re-estimation procedures
in a simulation study assessing operating characteristics including power and
type I error. We find that sample size re-estimation based on the popular
one-sample variance estimator results in overpowered trials. Moreover, sample
size re-estimation based on unbiased variance estimators such as the Xing-Ganju
variance estimator results in underpowered trials, as it is expected since an
overestimation of the variance and thus the sample size is in general required
for the re-estimation procedure to eventually meet the target power. Moreover,
we propose an inflation factor for the sample size re-estimation with the
Xing-Ganju variance estimator and show that this approach results in adequately
powered trials. Due to favorable features of Xing-Ganju variance estimator such
as unbiasedness and a distribution independent of the group means, the
inflation factor does not depend on the nuisance parameter and, therefore, can
be calculated prior to a trial.


title: Ultradistributional boundary values of harmonic functions on the sphere

abstract:
  We present a theory of ultradistributional boundary values for harmonic
functions defined on the Euclidean unit ball. We also give a characterization
of ultradifferentiable functions and ultradistributions on the sphere in terms
of their spherical harmonic expansions. To this end, we obtain explicit
estimates for partial derivatives of spherical harmonics, which are of
independent interest and refine earlier estimates by Calderon and Zygmund. We
apply our results to characterize the support of ultradistributions on the
sphere via Abel summability of their spherical harmonic expansions.


title:
A note on conical K\"ahler-Ricci flow on minimal elliptic K\"ahler
  surfaces

abstract:
  We prove that, under a semi-ampleness type assumption on the twisted
canonical line bundle, the conical K\"ahler-Ricci flow on a minimal elliptic
K\"ahler surface converges in the sense of currents to a generalized conical
K\"ahler-Einstein on its canonical model. Moreover, the convergence takes place
smoothly outside the singular fibers and the chosen divisor.


title:
Sharp global estimates for local and nonlocal porous medium-type
  equations in bounded domains

abstract:
  This paper provides a quantitative study of nonnegative solutions to
nonlinear diffusion equations of porous medium-type of the form $\partial_t u +
{\mathcal L}u^m=0$, $m>1$, where the operator ${\mathcal L}$ belongs to a
general class of linear operators, and the equation is posed in a bounded
domain $\Omega\subset{\mathbb R}^N$. As possible operators we include the three
most common definitions of the fractional Laplacian in a bounded domain with
zero Dirichlet conditions, and also a number of other nonlocal versions. In
particular, ${\mathcal L}$ can be a power of a uniformly elliptic operator with
$C^1$ coefficients. Since the nonlinearity is given by $u^m$ with $m>1$, the
equation is degenerate parabolic.
  The basic well-posedness theory for this class of equations has been recently
developed in [14,15]. Here we address the regularity theory: decay and
positivity, boundary behavior, Harnack inequalities, interior and boundary
regularity, and asymptotic behavior. All this is done in a quantitative way,
based on sharp a priori estimates. Although our focus is on the fractional
models, our results cover also the local case when ${\mathcal L}$ is a
uniformly elliptic operator, and provide new estimates even in this setting.
  A surprising aspect discovered in this paper is the possible presence of
non-matching powers for the long-time boundary behavior. More precisely, when
${\mathcal L}=(-\Delta)^s$ is a spectral power of the {Dirichlet} Laplacian
inside a smooth domain, we can prove that:
  - when $2s> 1-1/m$, for large times all solutions behave as ${\rm
dist}^{1/m}$ near the boundary;
  - when $2s\le 1-1/m$, different solutions may exhibit different boundary
behavior.
  This unexpected phenomenon is a completely new feature of the nonlocal
nonlinear structure of this model, and it is not present in the semilinear
elliptic equation ${\mathcal L}u^m=u$.


title: A Survey of Brain Inspired Technologies for Engineering

abstract:
  Cognitive engineering is a multi-disciplinary field and hence it is difficult
to find a review article consolidating the leading developments in the field.
The in-credible pace at which technology is advancing pushes the boundaries of
what is achievable in cognitive engineering. There are also differing
approaches to cognitive engineering brought about from the multi-disciplinary
nature of the field and the vastness of possible applications. Thus research
communities require more frequent reviews to keep up to date with the latest
trends. In this paper we shall dis-cuss some of the approaches to cognitive
engineering holistically to clarify the reasoning behind the different
approaches and to highlight their strengths and weaknesses. We shall then show
how developments from seemingly disjointed views could be integrated to achieve
the same goal of creating cognitive machines. By reviewing the major
contributions in the different fields and showing the potential for a combined
approach, this work intends to assist the research community in devising more
unified methods and techniques for developing cognitive machines.


title:
Construction and stability of blowup solutions for a non-variational
  semilinear parabolic system

abstract:
  We consider the following parabolic system whose nonlinearity has no gradient
structure: $$\left\{\begin{array}{ll} \partial_t u = \Delta u + |v|^{p-1}v,
\quad & \partial_t v = \mu \Delta v + |u|^{q - 1}u,\\ u(\cdot, 0) = u_0, \quad
& v(\cdot, 0) = v_0, \end{array}\right. $$ in the whole space $\mathbb{R}^N$,
where $p, q > 1$ and $\mu > 0$. We show the existence of initial data such that
the corresponding solution to this system blows up in finite time $T(u_0, v_0)$
simultaneously in $u$ and $v$ only at one blowup point $a$, according to the
following asymptotic dynamics: $$\left\{\begin{array}{c} u(x,t)\sim
\Gamma\left[(T-t) \left(1 + \dfrac{b|x-a|^2}{(T-t)|\log
(T-t)|}\right)\right]^{-\frac{(p + 1)}{pq - 1}},\\ v(x,t)\sim \gamma\left[(T-t)
\left(1 + \dfrac{b|x-a|^2}{(T-t)|\log (T-t)|}\right)\right]^{-\frac{(q + 1)}{pq
- 1}}, \end{array}\right.$$ with $b = b(p,q,\mu) > 0$ and $(\Gamma, \gamma) =
(\Gamma(p,q), \gamma(p,q))$. The construction relies on the reduction of the
problem to a finite dimensional one and a topological argument based on the
index theory to conclude. Two major difficulties arise in the proof: the
linearized operator around the profile is not self-adjoint even in the case
$\mu = 1$; and the fact that the case $\mu \ne 1$ breaks any symmetry in the
problem. In the last section, through a geometrical interpretation of
quantities of blowup parameters whose dimension is equal to the dimension of
the finite dimensional problem, we are able to show the stability of these
blowup behaviors with respect to perturbations in initial data.


title: Isolation probabilities in dynamic soft random geometric graphs

abstract:
  We consider soft random geometric graphs, constructed by distributing points
(nodes) randomly according to a Poisson Point Process, and forming links
between pairs of nodes with a probability that depends on their mutual
distance, the "connection function." Each node has a probability of being
isolated depending on the locations of the other nodes; we give analytic
expressions for the distribution of isolation probabilities. Keeping the node
locations fixed, the links break and reform over time, making a dynamic
network; this is a good model of a wireless ad-hoc network with communication
channels undergoing rapid fading. We use the above isolation probabilities to
investigate the distribution of the time to transmit information to all the
nodes, finding good agreement with numerics.


title: Realistic coasting cosmology from the Milne model

abstract:
  In the context of the recent synchronicity problem in $\Lambda$CDM cosmology,
coasting models such as the classic Milne model and the $R_h=ct$ model have
attracted much attention. Also, a very recent analysis of supernovae Ia data is
reported to favour models with constant expansion rates. We point out that the
nonempty $R_h=ct$ model has some known antecedents in the literature. Some of
these are published even before the discovery of the accelerated expansion and
were shown to have none of the cosmological problems and also that $H_0t_0=1$
and $\Omega_m/\Omega_{dark \; energy}$ = some constant of the order of unity.
In this paper, we also derive such a model by a complex extension of scale
factor in the Milne model.


title: Entropy of Reissner-Nordstr\"om-de Sitter black hole

abstract:
  Based on the consideration that the black hole horizon and the cosmological
horizon of Reissner-Nordstr\"om black hole in de Sitter space are not
independent each other, we conjecture the total entropy of the system should
have an extra term contributed from the entanglement between the two horizons,
except for the sum of the two horizon entropies. Making use of the globally
effective first law and the effective thermodynamic quantities, we derive the
total entropy and find that it will diverge as the two horizons tends to
coincide.


title:
Depth-Width Tradeoffs in Approximating Natural Functions with Neural
  Networks

abstract:
  We provide several new depth-based separation results for feed-forward neural
networks, proving that various types of simple and natural functions can be
better approximated using deeper networks than shallower ones, even if the
shallower networks are much larger. This includes indicators of balls and
ellipses; non-linear functions which are radial with respect to the $L_1$ norm;
and smooth non-linear functions. We also show that these gaps can be observed
experimentally: Increasing the depth indeed allows better learning than
increasing width, when training neural networks to learn an indicator of a unit
ball.