title:
Well separated trion and neutral excitons on superacid treated MoS2
  monolayers

abstract:
  Developments in optoelectronics and spin-optronics based on transition metal
dichalcogenide monolayers (MLs) need materials with efficient optical emission
and well-defined transition energies. In as-exfoliated MoS2 MLs the
photoluminescence (PL) spectra even at low temperature consists typically of
broad, overlapping contributions from neutral, charged excitons (trions) and
localized states. Here we show that in superacid treated MoS2 MLs the PL
intensity increases by up to 60 times at room temperature. The neutral and
charged exciton transitions are spectrally well separated in PL and
reflectivity at T=4 K, with linewidth for the neutral exciton of 15 meV, but
with similar intensities compared to the ones in as-exfoliated MLs at the same
temperature. Time resolved experiments uncover picoseconds recombination
dynamics analyzed separately for charged and neutral exciton emission. Using
the chiral interband selection rules, we demonstrate optically induced valley
polarization for both complexes and valley coherence for only the neutral
exciton.


title:
Determination of the Neutron-Capture Rate of 17C for the R-process
  Nucleosynthesis

abstract:
  With the R$^{3}$B-LAND setup at GSI we have measured exclusive
relative-energy spectra of the Coulomb dissociation of $^{18}$C at a projectile
energy around 425~AMeV on a lead target, which are needed to determine the
radiative neutron-capture cross sections of $^{17}$C into the ground state of
$^{18}$C. Those data have been used to constrain theoretical calculations for
transitions populating excited states in $^{18}$C. This allowed to derive the
astrophysical cross section $\sigma^{*}_{\mathrm{n}\gamma}$ accounting for the
thermal population of $^{17}$C target states in astrophysical scenarios. The
experimentally verified capture rate is significantly lower than those of
previously obtained Hauser-Feshbach estimations at temperatures
$T_{9}\leq{}1$~GK. Network simulations with updated neutron-capture rates and
hydrodynamics according to the neutrino-driven wind model as well as the
neutron-star merger scenario reveal no pronounced influence of neutron capture
of $^{17}$C on the production of second- and third-peak elements in contrast to
earlier sensitivity studies.


title: Concepts of Ferrovalley Material and Anomalous Valley Hall Effect

abstract:
  Valleytronics rooted in the valley degree of freedom is of both theoretical
and technological importance as it offers additional opportunities for
information storage and electronic, magnetic and optical switches. In analogy
to ferroelectric materials with spontaneous charge polarization in electronics,
as well as ferromagnetic materials with spontaneous spin polarization in
spintronics, here we introduce a new member of ferroic-family, i.e. a
ferrovalley material with spontaneous valley polarization. Combining a two-band
kp model with first-principles calculations, we show that 2H-VSe2 monolayer,
where the spin-orbit coupling coexists with the intrinsic exchange interaction
of transition-metal-d electrons, is such a room-temperature ferrovalley
material. We further predict that such system could demonstrate many
distinctive properties, for example, chirality-dependent optical band gap and
more interestingly, anomalous valley Hall effect. On account of the latter, a
series of functional devices based on ferrovalley materials, such as
valley-based nonvolatile random access memory, valley filter, are contemplated
for valleytronic applications.


title: Quantum discord as a tool for comparing collapse models and decoherence

abstract:
  The quantum to classical transition maybe caused by decoherence or by
dynamical collapse of the wave-function. We propose quantum discord as a tool,
1) for comparing and contrasting the role of a collapse model (Continuous
Spontaneous Localization) and various sources of decoherence (environmental and
fundamental), 2) for detecting collapse model and fundamental decoherence for
an experimentally demonstrated macroscopic entanglement. We discuss the
experimental times which will lead to the detection of either Continuous
Spontaneous Localization or fundamental decoherence. We further put bounds on
the collapse parameters from this experiment for quantum discord.


title:
Resonance-based Detection of Magnetic Nanoparticles and Microbeads Using
  Nanopatterned Ferromagnets

abstract:
  Biosensing with ferromagnet-based magnetoresistive devices has been dominated
by electrical detection of particle-induced changes to the devices' static
magnetic configuration. There are however potential advantages to be gained
from using field dependent, high frequency magnetization dynamics for magnetic
particle detection. Here we demonstrate the use of nano-confined ferromagnetic
resonances in periodically patterned magnetic films for the detection of
adsorbed magnetic particles with diameters ranging from 6 nm to 4 $\mu$m. The
nanopatterned films contain arrays of holes which can act as preferential
adsorption sites for small particles. Hole-localized particles act in unison to
shift the resonant frequencies of the various modes of the patterned layer with
shift polarities determined by the localization of each mode within the
nanopattern's repeating unit cell. The same polarity shifts are observed for a
large range of coverages, even when hole-localized particles are covered by
quasi-continuous particle sheets. For large particles however, preferential
adsorption no longer occurs, leading to resonance shifts with polarities which
are independent of the mode localization. Analogous shifts are seen in
continuous layers where, for small particles, the shift of the layer's
fundamental mode is typically about 10 times less than in patterned systems and
induced by relatively weak fields emanating beyond the particle in the
direction of the static applied field. This highlights the importance of having
confined modes consistently positioned with respect to nearby particles.


title: Lines in supersingular quartics

abstract:
  We show that the number of lines contained in a supersingular quartic surface
is 40 or at most 32, if the characteristic of the field equals 2, and it is
112, 58, or at most 52, if the characteristic equals 3. If the quartic is not
supersingular, the number of lines is at most 60 in both cases. We also give a
complete classification of large configurations of lines.


title:
A new angle for probing field-aligned irregularities with the Murchison
  Widefield Array

abstract:
  Electron density irregularities in the ionosphere are known to be
magnetically anisotropic, preferentially elongated along the lines of force.
While many studies of their morphology have been undertaken by topside sounding
and whistler measurements, it is only recently that detailed regional-scale
reconstructions have become possible, enabled by the advent of widefield radio
telescopes. Here we present a new approach for visualising and studying
field-aligned irregularities (FAIs), which involves transforming
interferometric measurements of TEC gradients onto a magnetic shell tangent
plane. This removes the perspective distortion associated with the oblique
viewing angle of the irregularities from the ground, facilitating the
decomposition of dynamics along and across magnetic field lines. We apply this
transformation to the dataset of Loi et al. [2015a], obtained on 15 October
2013 by the Murchison Widefield Array (MWA) radio telescope and displaying
prominent FAIs. We study these FAIs in the new reference frame, quantifying
field-aligned and field-transverse behaviour, examining time and altitude
dependencies, and extending the analysis to FAIs on sub-array scales. We show
that the inclination of the plane can be derived solely from the data, and
verify that the best-fit value is consistent with the known magnetic
inclination. The ability of the model to concentrate the fluctuations along a
single spatial direction may find practical application to future calibration
strategies for widefield interferometry, by providing a compact representation
of FAI-induced distortions.


title:
Vortex pinning and dynamics in high performance Sr0.6K0.4Fe2As2
  superconductor

abstract:
  We have studied vortex pinning and dynamics in a Sr0.6K0.4Fe2As2
superconducting tape with critical current density Jc~0.1 MA/cm2 at 4.2 K and
10 T. It is found that grain boundary pinning is dominant in the vortex pinning
mechanism. Furthermore, we observe large density of dislocations which can also
serve as effective pinning centers. We find that the temperature dependence of
critical current density is in agreement with the model of vortices pinned via
spatial fluctuation of charge carrier mean free path. Magnetic relaxation
measurement indicates that the magnetization depends on time in a logarithmic
way. The relaxation rate in the low and intermediate temperature region is
small, and it exhibits a weak temperature and field dependence. A crossover
from elastic creep to plastic creep regime is observed. Finally, we conclude a
vortex phase diagram for the high performance Sr0.6K0.4Fe2As2 superconducting
tape.


title:
Sur l'\'enum\'eration de structures discr\`etes, une approche par la
  th\'eorie des relations

abstract:
  Theory of relations is the framework of this thesis. It is about enumeration
of finite structures. Let $\mathscr C$ be a class of finite combinatorial
structures, the \emph{profile} of $\mathscr C$ is the function
$\varphi_{\mathscr C}$ which count, for every $n$, the number of members of
$\mathscr{C}$ defined on $n$ elements, isomorphic structures been identified.
The generating function for $\mathscr C$ is $\mathcal H_{\mathscr
C}(X):=\sum_{n\geqq 0}\varphi_{\mathscr C}(n)X^n$. Many results about the
behavior of the function $\varphi_{\mathscr C}$ have been obtained. Albert and
Atkinson have shown that the generating series of the profile of some classes
of permutations are algebraic. we show how this result extends to classes of
ordered binary structures using the notions of theory of relations. This is the
subject of the first part of this thesis. The second part is concerned with the
notion of minimality. An hereditary class of finite structures is minimal if it
is infinite and every proper hereditary subclass is finite. We show, in
particular, that ind-minimal classes are wqo ages and their number is the
continuum.
  The last part is motivated by the surprising phenomenon of the \emph{jump}
observed in the behavior of the profile of hereditary classes of finite
structures. We show that the profile of an hereditary classe made of ordered
structures which have finite monomorphic decomposition is a polynomial. We also
show that if the profile of a hereditary class of finite ordered binary
structures is not bounded by a polynomial then it is at least exponential. This
result generalizes the result obtained by Balogh, Bollob\'as and Morris (2006)
for ordered graphs.


title:
Photodiode Response in a CH$_3$NH$_3$PbI$_3$/CH$_3$NH$_3$SnI$_3$
  Heterojunction

abstract:
  Since the discovery of its photovoltaic properties organometallic salt
CH$_3$NH$_3$PbI$_3$ became the subject of vivid interest. The material exhibits
high light conversion efficiency, it lases in red color, and it can serve as
the basis for light emitting diodes and photodetectors. Here we report another
surprising feature of this material family, the photo-tunability of the diode
response of a heterojunction made of CH$_3$NH$_3$PbI$_3$ and its close
relative, CH$_3$NH$_3$SnI$_3$. In the dark state the device behaves as a diode,
with the Sn homologue acting as the "p" side. The junction is extremely
sensitive to illumination. A complete reversal of the diode polarity, the first
observation of its kind, is seen when the junction is exposed to red laser
light of 25 mW/cm$^2$ or larger power density. This finding opens up the
possibility for a novel class of opto-electronic devices.


title: Liveness-Based Garbage Collection for Lazy Languages

abstract:
  We consider the problem of reducing the memory required to run lazy
first-order functional programs. Our approach is to analyze programs for
liveness of heap-allocated data. The result of the analysis is used to preserve
only live data---a subset of reachable data---during garbage collection. The
result is an increase in the garbage reclaimed and a reduction in the peak
memory requirement of programs. While this technique has already been shown to
yield benefits for eager first-order languages, the lack of a statically
determinable execution order and the presence of closures pose new challenges
for lazy languages. These require changes both in the liveness analysis itself
and in the design of the garbage collector.
  To show the effectiveness of our method, we implemented a copying collector
that uses the results of the liveness analysis to preserve live objects, both
evaluated (i.e., in WHNF) and closures. Our experiments confirm that for
programs running with a liveness-based garbage collector, there is a
significant decrease in peak memory requirements. In addition, a sizable
reduction in the number of collections ensures that in spite of using a more
complex garbage collector, the execution times of programs running with
liveness and reachability-based collectors remain comparable.


title:
From Birth to Death of Protoplanetary Disks: Modeling Their Formation,
  Evolution, and Dispersal

abstract:
  Formation, evolution, and dispersal processes of protoplanetary disks are
investigated and the disk lifetime is estimated. Gravitational collapse of a
pre-stellar core forms both a central star and a protoplanetary disk. The
central star grows by accretion from the disk, and irradiation by the central
star heats up the disk and generates thermal wind, which results in the disk
dispersal. We calculate the evolution of protoplanetary disks from their parent
pre-stellar cores to dispersal of the disks. We find that the disk lifetimes of
typical pre-stellar cores are around 2--4 million years (Myr). A pre-stellar
core with high angular momentum forms a larger disk whose lifetime is long,
while a disk around a X-ray luminous star has a short lifetime. Integrating the
disk lifetimes under various mass and angular velocity of prestellar cores and
X-ray luminosities of young stellar objects, we obtain disk fraction at a given
stellar age and mean lifetime of the disks. Our model indicates that the mean
lifetime of protoplanetary disks is 3.7 Myr, which is consistent with the
observational estimate from young stellar clusters. We also find that the
dispersion of X-ray luminosity is needed to reproduce the observed disk
fraction.


title: Order-Invariance of Two-Variable Logic is Decidable

abstract:
  It is shown that order-invariance of two-variable first-logic is decidable in
the finite. This is an immediate consequence of a decision procedure obtained
for the finite satisfiability problem for existential second-order logic with
two first-order variables ($\mathrm{ESO}^2$) on structures with two linear
orders and one induced successor. We also show that finite satisfiability is
decidable on structures with two successors and one induced linear order. In
both cases, so far only decidability for monadic $\mathrm{ESO}^2$ has been
known. In addition, the finite satisfiability problem for $\mathrm{ESO}^2$ on
structures with one linear order and its induced successor relation is shown to
be decidable in non-deterministic exponential time.


title: Calder\'on's problem for p-Laplace type equations

abstract:
  We investigate a generalization of Calder\'on's problem of recovering the
conductivity coefficient in a conductivity equation from boundary measurements.
  As a model equation we consider the p-conductivity equation with p strictly
between one and infinity, which reduces to the standard conductivity equation
when p equals two, and to the p-Laplace equation when the conductivity is
constant.
  The thesis consists of results on the direct problem, boundary determination
and detecting inclusions. We formulate the equation as a variational problem
also when the conductivity may be zero or infinity in large sets. As a boundary
determination result we recover the first order derivative of a smooth
conductivity on the boundary. We use the enclosure method of Ikehata to recover
the convex hull of an inclusion of finite conductivity and find an upper bound
for the convex hull if the conductivity within an inclusion is zero or
infinite.


title:
A full, self-consistent, treatment of thermal wind balance on oblate
  fluid planets

abstract:
  The nature of the flow below the cloud level on Jupiter and Saturn is still
unknown. Relating the flow on these planets to perturbations in their density
field is key to the analysis of the gravity measurements expected from both the
Juno (Jupiter) and Cassini (Saturn) spacecrafts during 2016-17. Both missions
will provide latitude-dependent gravity fields, which in principle could be
inverted to calculate the vertical structure of the observed cloud-level zonal
flow on these planets. Theories to date connecting the gravity field and the
flow structure have been limited to potential theories under a barotropic
assumption, or estimates based on thermal wind balance that allow analyzing
baroclinic wind structures, but have made simplifying assumptions. Those
include the effects of the deviations from spherical symmetry, the centrifugal
force due to density perturbations, and self-gravitational effects of the
density perturbations. Recent studies attempted to include some effects but not
in a self-consistent manner. The present study introduces such a
self-consistent perturbation approach to the thermal wind balance that
incorporates all physical effects, and applies it to several example wind
structures, both barotropic and baroclinic. The contribution of each term is
analyzed, and the results are compared in the barotropic limit to those of
potential theory. It is found that the dominant balance involves the original
simplified thermal wind approach. This balance produces a good
order-of-magnitude estimate of the gravitational moments, and is able,
therefore, to address the order one question of how deep the flows are given
measurements of gravitational moments. The additional terms are significantly
smaller and none of these terms is dominant, so any approximation attempting to
improve over the simplified thermal wind approach needs to include all other
terms.


title: Quantization of Conductance Minimum and Index Theorem

abstract:
  We discuss the minimum value of the zero-bias differential conductance
$G_{\textrm{min}}$ in a junction consisting of a normal metal and a nodal
superconductor preserving time-reversal symmetry. Using the quasiclassical
Green function method, we show that $G_{\textrm{min}}$ is quantized at $
(4e^2/h) N_{\mathrm{ZES}}$ in the limit of strong impurity scatterings in the
normal metal. The integer $N_{\mathrm{ZES}}$ represents the number of perfect
transmission channels through the junction. An analysis of the chiral symmetry
of the Hamiltonian indicates that $N_{\mathrm{ZES}}$ corresponds to the
Atiyah-Singer index in mathematics.


title: Nef vector bundles on a projective space with first Chern class three

abstract:
  We classify nef vector bundles on a projective space with first Chern class
three over an algebraically closed field of characteristic zero; we see, in
particular, that these nef vector bundles are globally generated if the second
Chern class is less than eight, and that there exist nef but non-globally
generated vector bundles with second Chern class eight and nine on a projective
plane.


title: Scene Parsing with Integration of Parametric and Non-parametric Models

abstract:
  We adopt Convolutional Neural Networks (CNNs) to be our parametric model to
learn discriminative features and classifiers for local patch classification.
Based on the occurrence frequency distribution of classes, an ensemble of CNNs
(CNN-Ensemble) are learned, in which each CNN component focuses on learning
different and complementary visual patterns. The local beliefs of pixels are
output by CNN-Ensemble. Considering that visually similar pixels are
indistinguishable under local context, we leverage the global scene semantics
to alleviate the local ambiguity. The global scene constraint is mathematically
achieved by adding a global energy term to the labeling energy function, and it
is practically estimated in a non-parametric framework. A large margin based
CNN metric learning method is also proposed for better global belief
estimation. In the end, the integration of local and global beliefs gives rise
to the class likelihood of pixels, based on which maximum marginal inference is
performed to generate the label prediction maps. Even without any
post-processing, we achieve state-of-the-art results on the challenging
SiftFlow and Barcelona benchmarks.


title: Fixed point structure of the Abelian Higgs model

abstract:
  The order of the superconducting phase transition is analyzed via the
functional renormalization group approach. For the first time, we derive fully
analytic expressions for the $\beta$ functions of the charge and the
self-coupling in the Abelian Higgs model with one complex scalar field in $d=3$
dimensions that support the existence of two charged fixed points: an infrared
(IR) stable fixed point describing a second-order phase transition and a
tritical fixed point controlling the region of the parameter space that is
attracted by the former one. It is found that the region separating first- and
second-order transitions can be uniquely characterized by the Ginzburg-Landau
parameter $\kappa$, and the system undergoes a second order transition, only if
$\kappa>\kappa_c \approx 0.62/\sqrt2$.


title: On maximal parabolic regularity for non-autonomous parabolic operators

abstract:
  We consider linear inhomogeneous non-autonomous parabolic problems associated
to sesquilinear forms, with discontinuous dependence of time. We show that for
these problems, the property of maximal parabolic regularity can be
extrapolated to time integrability exponents $r\neq 2$. This allows us to prove
maximal parabolic $L^r$-regularity for discontinuous non-autonomous
second-order divergence form operators in very general geometric settings and
to prove existence results for related quasilinear equations.


title: Topological Insulators from Electronic Superstructures

abstract:
  The possibility of realizing topological insulators by spontaneous formation
of electronic superstructure is theoretically investigated in a minimal
two-orbital model including both the spin-orbit coupling and electron
correlations on a triangular lattice. Using the mean-field approximation, we
show that the model exhibits several different types of charge ordered
insulators, where the charge disproportionation forms a honeycomb or kagome
superstructure. We find that the charge ordered insulators in the presence of
strong spin-orbit coupling can be topological insulators showing quantized spin
Hall conductivity. Their band gap is dependent on electron correlations as well
as the spin-orbit coupling, and even vanishes with showing the massless Dirac
dispersion at the transition to a trivial charge ordered insulator. Our results
suggest a new route to realize and control topological states of quantum matter
by the interplay between the spin-orbit coupling and electron correlations.


title:
The conducting spin-crossover compound combining Fe(II) cation complex
  with TCNQ in a fractional reduction state

abstract:
  The radical anion salt [Fe{HC(pz)3}2](TCNQ)3 demonstrating conductivity and
spin-crossover transition (SCO) associated with Fe(II) complex cation subsystem
has been synthesized and structurally characterized. A pronounced change of the
dc resistivity and a robust broadening of the EPR signal triggered by the SCO
transition are found. Enhanced EPR line broadening is interpreted in terms of
cross relaxation between the TCNQ and Fe(II) spin subsystems


title: A simple proof of the short-time existence and uniqueness for Ricci flow

abstract:
  In this short note we give a simple proof for the local existence and
uniqueness for the Ricci flow on a compact manifold. We suggest a new setting
for studying the space of Riemannian metrics on a compact manifold.


title:
Manifestation of Universality in the Asymmetric Helium Trimer and in the
  Halo Nucleus $^{22}$C

abstract:
  We prove that the corner angle distributions in the bound three-body system
AAB, which consists of two particles of type A and one particle of type B,
approach universal form if the pair AA has a virtual state at zero energy and
the binding energy of AAB goes to zero. We derive explicit expressions for the
universal corner angle distributions in terms of elementary functions, which
depend solely on the mass ratio m(A)/m(B) and do not depend on pair
interactions. On the basis of experimental data and calculations we demonstrate
that such systems as the asymmetric Helium trimer $^3$He$^4$He$_2$ and the halo
nucleus $^{22}$C exhibit universal features. Thus our result establishes an
interesting link between atomic and nuclear physics through the few-body
universality.

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


title: On an inverse problem for Sturm-Liouville equation

abstract:
  In this study, the theorem on necessary and sufficient conditions for the
solvability of inverse problem for Sturm-Liouville operator with discontinuous
coefficient is proved and the algorithm of reconstruction of potential from
spectral data (eigenvalues and normalizing numbers) is given.


title:
The discrete-time quaternionic quantum walk and the second weighted zeta
  function on a graph

abstract:
  We define the quaternionic quantum walk on a finite graph and investigate its
properties. This walk can be considered as a natural quaternionic extension of
the Grover walk on a graph. We explain the way to obtain all the right
eigenvalues of a quaternionic matrix and a notable property derived from the
unitarity condition for the quaternionic quantum walk. Our main results
determine all the right eigenvalues of the quaternionic quantum walk by using
complex eigenvalues of the quaternionic weighted matrix which is easily
derivable from the walk. Since our derivation is owing to a quaternionic
generalization of the determinant expression of the second weighted zeta
function, we explain the second weighted zeta function and the relationship
between the walk and the second weighted zeta function.


title:
Towards an understanding of ramified extensions of structured ring
  spectra

abstract:
  We propose topological Hochschild homology as a tool for measuring
ramification of maps of structured ring spectra. We determine second order
topological Hochschild homology of the $p$-local integers. For the tamely
ramified extension of the map from the connective Adams summand to $p$-local
complex topological K-theory we determine the relative topological Hochschild
homology and show that it detects the tame ramification of this extension. We
also determine relative topological Hochschild homology for the
complexification map from connective real to complex topological K-theory and
for some quotient maps with commutative quotients.


title: Revisiting Stochastic Variability of AGNs with Structure Functions

abstract:
  Discrepancies between reported structure function (SF) slopes and their
overall flatness as compared to expectations from the damped random walk (DRW)
model, which generally well describes the variability of active galactic nuclei
(AGNs), have triggered us to study this problem in detail. We review common AGN
variability observables and identify their most common problems. Equipped with
this knowledge, we study ~9000 r-band AGN light curves from Stripe 82 of the
Sloan Digital Sky Survey, using SFs described by stochastic processes with the
power exponential covariance matrix of the signal. We model the "subensemble"
SFs in the redshift-absolute magnitude bins with the full SF equation
(including the turnover and the noise part) and a single power law (SPL; in the
"red noise regime" after subtracting the noise term). The distribution of
full-equation SF (SPL) slopes peaks at gamma = 0.55 +/- 0.08 (0.52 +/- 0.06)
and is consistent with the DRW model. There is a hint of a weak correlation of
gamma with the luminosity and a lack of correlation with the black hole mass.
The typical decorrelation timescale in the optical is tau = 0.97 +/- 0.46 year.
The SF amplitude at one year obtained from the SPL fitting is SF_0 = 0.22 +/-
0.06 mag and is overestimated because the SF is already at the turnover part,
so the true value is SF_0 = 0.20 +/- 0.06 mag. The asymptotic variability is
SF_\infty = 0.25 +/- 0.06 mag. It is strongly anticorrelated with both the
luminosity and the Eddington ratio and is correlated with the black hole mass.
The reliability of these results is fortified with Monte Carlo simulations.


title:
Influence of the impurity scattering on charge transport in
  unconventional superconductor junctions

abstract:
  We study the influence of non-magnetic impurity scatterings on the tunneling
conductance of a junction consisting of a normal metal and a disordered
unconventional superconductor by solving the quasiclassical Eilenberger
equation self-consistently. We find that the impurity scatterings in both the
Born and unitary limits affect the formation of the Andreev bound states and
modify strongly the tunneling spectra around zero bias. Our results are
interpreted well by the appearance of odd-frequency Cooper pairs near the
interface and by the divergent behavior of the impurity self-energy. The
present paper provides a useful tool to identify the pairing symmetry of
unconventional superconductors in experiments.


title: An anelastic approximation arising in astrophysics

abstract:
  We identify the asymptotic limit of the compressible non-isentropic
Navier-Stokes system in the regime of low Mach, low Froude and high Reynolds
number. The system is driven by a long range gravitational potential. We show
convergence to an anelastic system for ill-prepared initial data. The proof is
based on frequency localized Strichartz estimates for the acoustic equation
based on the recent work of Metcalfe and Tataru.


title:
First Experimental Demonstration of Secure NFV Orchestration over an
  SDN-Controlled Optical Network with Time-Shared Quantum Key Distribution
  Resources

abstract:
  We demonstrate, for the first time, a secure optical network architecture
that combines NFV orchestration and SDN control with quantum key distribution
(QKD) technology. A novel time-shared QKD network design is presented as a
cost-effective solution for practical networks.


title: Determination of a jump by Fourier and Fourier-Chebyshev series

abstract:
  By observing the equivalence of assertions on determining the jump of a
function by its differentiated or integrated Fourier series, we generalize a
previous result of Kvernadze, Hagstrom and Shapiro to the whole class of
functions of harmonic bounded variation and without finiteness assumption on
the number of discontinuities. Two results on determination of jump
discontinuities by means of the tails of integrated Fourier-Chebyshev series
are derived.


title: An isoperimetric inequality for planar triangulations

abstract:
  We prove a discrete analogue to a classical isoperimetric theorem of Weil for
surfaces with non-positive curvature. It is shown that hexagons in the
triangular lattice have maximal volume among all sets of a given boundary in
any triangulation with minimal degree 6.


title: The exact Laplacian spectrum for the Dyson hierarchical network

abstract:
  We consider the Dyson hierarchical graph $\mathcal{G}$, that is a weighted
fully-connected graph, where the pattern of weights is ruled by the parameter
$\sigma \in (1/2, 1]$. Exploiting the deterministic recursivity through which
$\mathcal{G}$ is built, we are able to derive explicitly the whole set of the
eigenvalues and the eigenvectors for its Laplacian matrix. Given that the
Laplacian operator is intrinsically implied in the analysis of dynamic
processes (e.g., random walks) occurring on the graph, as well as in the
investigation of the dynamical properties of connected structures themselves
(e.g., vibrational structures and the relaxation modes), this result allows
addressing analytically a large class of problems. In particular, as examples
of applications, we study the random walk and the continuous-time quantum walk
embedded in $\mathcal{G}$, and the relaxation times of a polymer whose
structure is described by $\mathcal{G}$.


title:
Estimating 3D Trajectories from 2D Projections via Disjunctive Factored
  Four-Way Conditional Restricted Boltzmann Machines

abstract:
  Estimation, recognition, and near-future prediction of 3D trajectories based
on their two dimensional projections available from one camera source is an
exceptionally difficult problem due to uncertainty in the trajectories and
environment, high dimensionality of the specific trajectory states, lack of
enough labeled data and so on. In this article, we propose a solution to solve
this problem based on a novel deep learning model dubbed Disjunctive Factored
Four-Way Conditional Restricted Boltzmann Machine (DFFW-CRBM). Our method
improves state-of-the-art deep learning techniques for high dimensional
time-series modeling by introducing a novel tensor factorization capable of
driving forth order Boltzmann machines to considerably lower energy levels, at
no computational costs. DFFW-CRBMs are capable of accurately estimating,
recognizing, and performing near-future prediction of three-dimensional
trajectories from their 2D projections while requiring limited amount of
labeled data. We evaluate our method on both simulated and real-world data,
showing its effectiveness in predicting and classifying complex ball
trajectories and human activities.


title: Towards Better: A motivated introduction to better-quasi-orders

abstract:
  The well-quasi-orders (WQO) play an important role in various fields such as
Computer Science, Logic or Graph Theory. Since the class of WQOs lacks closure
under some important operations, the proof that a certain quasi-order is WQO
consists often of proving it enjoys a stronger and more complicated property,
namely that of being a better-quasi-order (BQO).
  Several articles contains valuable introductory material to the theory of
BQOs. However, a textbook entitled "Introduction to better-quasi-order theory"
is yet to be written. Here is an attempt to give a motivated and self-contained
introduction to the deep concept defined by Nash-Williams that we would expect
to find in such a textbook.


title:
Vector chirality for effective total momentum $J_{\textrm{eff}}$ in a
  nonfrustrated Mott insulator: Effects of strong spin-orbit coupling and
  broken inversion symmetry

abstract:
  I propose the emergence of the spin-orbital-coupled vector chirality in a
non-frustrated Mott insulator with the strong spin-orbit coupling due to
$ab$-plane's inversion-symmetry (IS) breaking. I derive the superexchange
interactions for a $t_{2g}$-orbital Hubbard model on a square lattice with the
strong spin-orbit coupling and the IS-breaking-induced hopping integrals, and
explain the microscopic origins of the Dzyaloshinsky-Moriya (DM) -type and the
Kitaev-type interactions. Then, by adopting the mean-field approximation to a
minimal model including only the Heisenberg-type and the DM-type
nearest-neighbor interactions, I show that the IS breaking causes the
spin-orbital-coupled chirality as a result of stabilizing the screw state. I
also highlight the limit of the hard-pseudospin approximation in discussing the
stability of the screw states in the presence of both the DM-type and the
Kitaev-type interactions, and discuss its meaning. I finally discuss the
effects of tetragonal crystal field and $J_{\textrm{eff}}=\frac{3}{2}$ states,
and the application to the iridates near the $[001]$ surface of
Sr$_{2}$IrO$_{4}$ and the interface between Sr$_{2}$IrO$_{4}$ and
Sr$_{3}$Ir$_{2}$O$_{7}$.


title:
Predicting the intensity of partially observed data from a revisited
  kriging for point processes

abstract:
  We consider a stationary and isotropic spatial point process whose a
realisation is observed within a large window. We assume it to be driven by a
stationary random field $U$. In order to predict the local intensity of the
point process, $\lambda (x|U)$, we propose to define the first- and
second-order characteristics of a random field, defined as the regularized
counting process, from the ones of the point process and to interpolate the
local intensity by using a kriging adapted to the regularized process.


title:
A non-relativistic Model of Plasma Physics Containing a Radiation
  Reaction Term

abstract:
  While a fully relativistic collisionless plasma is modeled by the
Vlasov-Maxwell system a good approximation in the non-relativistic limit is
given by the Vlasov-Poisson system. We modify the Vlasov-Poisson system so that
damping due to the relativistic effect of radiation reaction is included. We
prove the existence and uniqueness as well as the higher regularity of local
classical solutions. These theorems also include the higher regularity of
classical solutions of the Vlasov-Poisson system depending on the regularity of
the initial datum.


title: Casimir Force between a Half-Space and a Plate of Finite Thickness

abstract:
  Zero-frequency Casimir theory is analyzed from different viewpoints, focusing
on the Drude-plasma issue that turns up when one considers thermal corrections
to the Casimir force. The problem is that the plasma model, although leaving
out dissipation in the material, apparently gives the best agreement with
recent experiments. We consider a dielectric plate separated from a dielectric
half-space by a vacuum gap, both media being similar. We consider the following
categories: (1) Making use of the statistical mechanical method developed by
H{\o}ye and Brevik (1998), implying that the quantized electromagnetic field is
replaced by interaction between dipole moments oscillating in harmonic
potentials, we first verify that the Casimir force is in agreement with the
Drude prediction. No use of Fresnel's reflection coefficients is made at this
stage. (2) Then turning to the field theoretical description implying use of
the reflection coefficients, we derive results in agreement with the forgoing
when first setting the frequency equal to zero, before letting the permittivity
becoming large. With the plasma relation the reflection coefficient for TE zero
frequency modes depend on the component of the wave vector parallel to the
surfaces and lies between 0 and 1. This contradicts basic electrostatic theory.
(3) Turning to high permeability magnetic materials the TE zero frequency mode
describes the static magnetic field in the same way as the TM zero frequency
modes describe the static electric fields in electrostatics. With the plasma
model magnetic fields, except for a small part, can not pass through metals.
i.e.~metals effectively become superconductors. However, recent experimental
results clearly favor the plasma model. We shortly discuss a possible
explanation for this apparent conflict with electrostatics.


title:
Resonant vibrational-excitation cross sections and rate constants for
  low-energy electron scattering by molecular oxygen

abstract:
  Resonant vibrational-excitation cross sections and rate constants for
electron scattering by molecular oxygen are presented. Transitions between all
42 vibrational levels of O$_2(\textrm{X}\ ^3\Sigma_g^- $) are considered.
Molecular rotations are parameterized by the rotational quantum number $J$
which is considered in the range 1 to 151. The lowest four resonant states of
O$_2^-$, $^2\Pi_g$, $^2\Pi_u$, $^4\Sigma_u^-$ and $^2\Sigma_u^-$, are taken
into account. The calculations are performed using the fixed-nuclei R-matrix
approach to determine the resonance positions and widths, and the boomerang
model to characterize the nuclei motion. Two energy regions below and above
4~eV are investigated: the first one is characterized by sharp structures in
the cross section, and the second by a broad resonance peaked at 10~eV. The
computed cross sections are compared with theoretical and experimental results
available in literature for both the energy regions, and are made available for
use by modelers. The effect of including rotational motion is found to be
non-negligible.


title: An algorithm for the optimization of finite element integration loops

abstract:
  We present an algorithm for the optimization of a class of finite element
integration loop nests. This algorithm, which exploits fundamental mathematical
properties of finite element operators, is proven to achieve a locally optimal
operation count. In specified circumstances the optimum achieved is global.
Extensive numerical experiments demonstrate significant performance
improvements over the state of the art in finite element code generation in
almost all cases. This validates the effectiveness of the algorithm presented
here, and illustrates its limitations.


title: Convergence of the Gutt Star Product: A strict Deformation Quantization

abstract:
  This work is the final version of my master thesis. Many, but not all of its
key results are already available as a preprint with Chiara Esposito and Stefan
Waldmann on arxiv.org under the title "Convergence of the Gutt Star Product",
which has been submitted to a journal. The main goal of this work is to
understand a certain deformation of the commutative product on the symmetric
tensor algebra over a given (locally convex) Lie algebra in a topological
setting. Therefore, the tensor algebra over the Lie algebra is topologized in a
locally convex manner. This finally provides a new example of a strict
deformation quantization, i.e. a continuous star product. The related formal
star product was found by Simone Gutt and is therefore called the Gutt star
product. Together with this star product, the symmetric tensor algebra is
isomorphic to the universal enveloping algebra of the Lie algebra. Hence, this
work also presents an explicit locally convex topology on the universal
enveloping algebra of certain locally convex Lie algebras. Since this
construction has good functorial properties, it is also an interesting object
of study not only in quantization and quantum group theory, but also in Lie
theory.


title: The two-particle problem in comb-like structures

abstract:
  Encounters between walkers performing a random motion on an appropriate
structure can describe a wide variety of natural phenomena ranging from
pharmacokinetics to foraging. On homogeneous structures the asymptotic
encounter probability between two walkers is (qualitatively) independent of
whether both walkers are moving or one is kept fixed. On infinite comb-like
structures this is no longer the case and here we deepen the mechanisms
underlying the emergence of a finite probability that two random walkers will
never meet, while one single random walker is certain to visit any site. In
particular, we introduce an analytical approach to address this problem and
even more general problems such as the case of two walkers with different
diffusivity, particles walking on a finite comb and on arbitrary bundled
structures, possibly in the presence of loops. Our investigations are both
analytical and numerical and highlight that, in general, the outcome of a
reaction involving two reactants on a comb-like architecture can be strongly
different according to whether both reactants are moving (no matter their
relative diffusivities) or only one, and according to the density of short-cuts
among the branches.


title: Distributed Entity Disambiguation with Per-Mention Learning

abstract:
  Entity disambiguation, or mapping a phrase to its canonical representation in
a knowledge base, is a fundamental step in many natural language processing
applications. Existing techniques based on global ranking models fail to
capture the individual peculiarities of the words and hence, either struggle to
meet the accuracy requirements of many real-world applications or they are too
complex to satisfy real-time constraints of applications.
  In this paper, we propose a new disambiguation system that learns specialized
features and models for disambiguating each ambiguous phrase in the English
language. To train and validate the hundreds of thousands of learning models
for this purpose, we use a Wikipedia hyperlink dataset with more than 170
million labelled annotations. We provide an extensive experimental evaluation
to show that the accuracy of our approach compares favourably with respect to
many state-of-the-art disambiguation systems. The training required for our
approach can be easily distributed over a cluster. Furthermore, updating our
system for new entities or calibrating it for special ones is a computationally
fast process, that does not affect the disambiguation of the other entities.


title:
A novel flexible field-aligned coordinate system for tokamak edge plasma
  simulation

abstract:
  Tokamak plasmas are confined by a magnetic field that limits the particle and
heat transport perpendicular to the field. Parallel to the field the ionised
particles can move freely, so to obtain confinement the field lines are
"closed" (ie. form closed surfaces of constant poloidal flux) in the core of a
tokamak. Towards, the edge, however, the field lines begin to intersect
physical surfaces, leading to interaction between neutral and ionised
particles, and the potential melting of the material surface. Simulation of
this interaction is important for predicting the performance and lifetime of
future tokamak devices such as ITER. Field-aligned coordinates are commonly
used in the simulation of tokamak plasmas due to the geometry and magnetic
topology of the system. However, these coordinates are limited in the geometry
they allow in the poloidal plane due to orthogonality requirements. A novel 3D
coordinate system is proposed herein that relaxes this constraint so that any
arbitrary, smoothly varying geometry can be matched in the poloidal plane while
maintaining a field-aligned coordinate. This system is implemented in BOUT++
and tested for accuracy using the method of manufactured solutions. A MAST edge
cross-section is simulated using a fluid plasma model and the results show
expected behaviour for density, temperature, and velocity. Finally, simulations
of an isolated divertor leg are conducted with and without neutrals to
demonstrate the ion-neutral interaction near the divertor plate and the
corresponding beneficial decrease in plasma temperature.


title: The omega-square hypothesis for the seismic source

abstract:
  The omega-square hypothesis assumes that the ground displacement u(t) in the
far-field zone decays as the inverse square of frequency in the range ~1-30 Hz.
This empirical fact remains theoretically unjustified. Our analysis of the
problem is based on an integral representation of u(t) in terms of the source
time function f and on the spectrum analysis of local features in f. The goal
is to select the local features that will enable one to generate the
omega-square behavior of u(t) on a large set of receivers. We found two
appropriate fragments of f : first , f exhibits a local inverse-square-root
behavior near the rupture front where the frontal surface is piecewise smooth
(but not smooth and not rough ); and second, f is bounded near the rupture
front where the frontal surface has a slight roughness (the Hurst parameter
near 1). These facts can be useful for understanding the omega-square spectral
behavior of the kinematic source models.


title:
A Factorization Machine Framework for Testing Bigram Embeddings in
  Knowledgebase Completion

abstract:
  Embedding-based Knowledge Base Completion models have so far mostly combined
distributed representations of individual entities or relations to compute
truth scores of missing links. Facts can however also be represented using
pairwise embeddings, i.e. embeddings for pairs of entities and relations. In
this paper we explore such bigram embeddings with a flexible Factorization
Machine model and several ablations from it. We investigate the relevance of
various bigram types on the fb15k237 dataset and find relative improvements
compared to a compositional model.


title:
Accuracy of Discrete Markov Approximation in the Problems of Estimation
  of Random Field Characteristics

abstract:
  The covariance matrix of measurements of Markov random fields (processes) has
useful properties that allow to develop effective computational algorithms for
many problems in the study of Markov fields on the basis of field observations
(parametric identification problems, filtering problems, interpolation problems
and others). Therefore, approximation of arbitrary random fields by Markov
fields is of great interest, as it gives an opportunity to use computationally
efficient algorithms of Markov fields analysis to study them. The paper deals
with approximation of the covariance matrix of the field being observed with
the help of covariance matrix of a multiply connected (m-connected) Markov
field. Using computer simulation, the accuracy of such replacements at
different values of the connectivity coefficient m for the problem of
parametric identification of deterministic component of the field has been
studied. Various models of deterministic polynomial component of the field and
a number of covariance functions that are often used as a mathematical model of
real random noise and measurements noise have been reviewed. It has been shown
that for many problems such approximation, even at small connectivity m values
of approximating Markov field, provides necessary accuracy. This allows to
achieve good compromise between accuracy of the estimates and complexity of
calculating them.


title:
Earth's albedo variations 1998-2014 as measured from ground-based
  earthshine observations

abstract:
  The Earth's albedo is a fundamental climate parameter for understanding the
radiation budget of the atmosphere. It has been traditionally measured from
space platforms, but also from the ground for sixteen years from Big Bear Solar
Observatory by observing the Moon. The photometric ratio of the dark
(earthshine) to the bright (moonshine) sides of the Moon is used to determine
nightly anomalies in the terrestrial albedo, with the aim is of quantifying
sustained monthly, annual and/or decadal changes. We find two modest decadal
scale cycles in the albedo, but with no significant net change over the sixteen
years of accumulated data. Within the evolution of the two cycles, we find
periods of sustained annual increases, followed by comparable sustained
decreases in albedo. The evolution of the earthshine albedo is in remarkable
agreement with that from the CERES instruments, although each method measures
different slices of the Earth's Bond albedo.


title: Commensurabilities between ETNOs: a Monte Carlo survey

abstract:
  Many asteroids in the main and trans-Neptunian belts are trapped in mean
motion resonances with Jupiter and Neptune, respectively. As a side effect,
they experience accidental commensurabilities among themselves. These
commensurabilities define characteristic patterns that can be used to trace the
source of the observed resonant behaviour. Here, we explore systematically the
existence of commensurabilities between the known ETNOs using their
heliocentric and barycentric semimajor axes, their uncertainties, and Monte
Carlo techniques. We find that the commensurability patterns present in the
known ETNO population resemble those found in the main and trans-Neptunian
belts. Although based on small number statistics, such patterns can only be
properly explained if most, if not all, of the known ETNOs are subjected to the
resonant gravitational perturbations of yet undetected trans-Plutonian planets.
We show explicitly that some of the statistically significant
commensurabilities are compatible with the Planet Nine hypothesis; in
particular, a number of objects may be trapped in the 5:3 and 3:1 mean motion
resonances with a putative Planet Nine with semimajor axis of about 700 au.


title: Ultrafast and gigantic spin injection in semiconductors

abstract:
  The injection of spin currents in semiconductors is one of the big challenges
of spintronics. Motivated by the ultrafast demagnetisation and spin injection
into metals, we propose an alternative femtosecond route based on the laser
excitation of superdiffusive spin currents in a ferromagnet such as Ni. Our
calculations show that even though only a fraction of the current crosses the
Ni-Si interface, the laser-induced creation of strong transient electrical
fields at a ferromagnet-semiconductor interface allows for the injection of
chargeless spin currents with a record spin polarisations of 80%. Beyond that
they are pulsed on the time scale of 100 femtoseconds which opens the door for
new experiments and ultrafast spintronics.


title: Categorification of Algebras: 2-Algebras

abstract:
  This paper introduces a categorification of $k$-algebras called 2 -algebras,
where k is a commutative ring. We define the 2-algebras as a 2-category with
single object in which collections of all 1-morphisms and all 2-morphisms are
k-algebras. It is shown that the category of 2 -algebras is equivalent to the
category of crossed modules in commutative k -algebras. Also we define the
notion of homotopy for 2-algebras and we explore the relations of crossed
module homotopy and 2-algebra homotopy.


title: Eigenvalues of Weighted-Laplacian under the extended Ricci flow

abstract:
  Let $\Delta_\varphi = \Delta -\nabla \varphi \nabla$ be a symmetric diffusion
operator with an invariant weighted volume measure $d\mu = e^{-\varphi} dv$ on
an $n$-dimensional compact Riemannian manifold $(M,g)$, where $g=g(t)$ solves
the extended Ricci flow. In this article we study the evolution and monotonicty
of the first nonzero eigenvalue of $\Delta_\varphi$ and we obatin several
monotone quantities along the extended Ricci flow and its volume preserving
version under some technical assumption. We also show that the eigenvalues
diverge in a finite time for the case $n\geq 3$. Our results are natural
extension of some known results for Laplace-Beltrami operator under various
geometric flows.


title:
Locally compact groups approximable by subgroups isomorphic to $\mathbb
  Z$ or $\mathbb R$

abstract:
  Let $G$ be a locally compact topological group, $G_0$ the connected component
of its identity element, and comp(G) the union of all compact subgroups. A
topological group will be called inductively monothetic if any subgroup
generated (as a topological group) by finitely many elements is generated (as a
topological group) by a single element. The space SUB(G) of all closed
subgroups of $G$ carries a compact Hausdorff topology called the Chabauty
topology. Let $F_1(G)$, respectively, $R_1(G)$, denote the subspace of all
discrete subgroups isomorphic to $\mathbb Z$, respectively, all subgroups
isomorphic to $\mathbb R$. It is shown that a necessary and sufficient
condition for $G\in\overline{F_1(G)}$ to hold is that $G$ is abelian, and
either that $G\cong \mathbb R\times {\rm comp}(G)$ and $G/G_0$ is inductively
monothetic, or else that $G$ is discrete and isomorphic to a subgroup of
$\mathbb Q$. It is further shown that a necessary and sufficient condition for
$G\in\overline{R_1(G)}$ to hold is that $G\cong\mathbb R\times C$ for a compact
connected abelian group $C$.


title: Cluster Glass Transition of Ultrasoft-Potential Fluids at High Density

abstract:
  Using molecular dynamics simulation, we investigate the slow dynamics of a
supercooled binary mixture of soft particles interacting with a generalized
Hertzian potential. At low density, it displays typical slow dynamics near its
glass transition temperature. At higher densities, particles bond together,
forming clusters, and the clusters undergo the glass transition. The number of
particles in a cluster increases one by one as the density increases. We
demonstrate that there exist the multiple cluster-glass phases characterized by
a different number of particles per cluster, each of which is separated by
distinct minima. Surprisingly, a so-called higher order singularity of the
mode-coupling theory signaled by a logarithmic relaxation is observed in the
vicinity of the boundaries between monomer and cluster glass phases. The system
also exhibits rich and anomalous dynamics in the cluster glass phases, such as
the decoupling of the self- and collective dynamics.


title: The Fundamental Theorem for weak braided bimonads

abstract:
  The theories of (Hopf) bialgebras and weak (Hopf) bialgebras have been
introduced for vector space categories over fields and make heavily use of the
tensor product. As first generalisations, these notions were formulated for
monoidal categories, with braidings if needed. The present authors developed a
theory of bimonads and Hopf monads $H$ on arbitrary categories $\mathbb{A}$,
employing distributive laws, allowing for a general form of the Fundamental
Theorem for Hopf algebras. For $\tau$-bimonads $H$, properties of braided
(Hopf) bialgebras were captured by requiring a Yang-Baxter operator $\tau:HH\to
HH$. The purpose of this paper is to extend the features of weak (Hopf)
bialgebras to this general setting including an appropriate form of the
Fundamental Theorem. This subsumes the theory of braided Hopf algebras (based
on weak Yang-Baxter operators) as considered by Alonso \'Alvarez and others.


title: A note on the ranking of earthquake forecasts

abstract:
  The ranking problem of earthquake forecasts is considered. We formulate
simple statistical requirements to forecasting quality measure R and analyze
some R-ranking methods on this basis, in particular, the pari-mutuel gambling
method by Zechar&Zhuang (2014).


title: On the dimension of classifying spaces for families of abelian subgroups

abstract:
  We show that a finitely generated abelian group $G$ of torsion-free rank
$n\geq 1$ admits a $n+r$ dimensional model for the classifying space with
isotropy in the family of subgroups of torsion-free rank less than or equal to
$r\geq 0$.


title:
3-Leibniz bialgebra in $N=6$ Chern-Simons gauge theories, multiple M2 to
  D2 branes and vice versa

abstract:
  Constructing M2-brane and its boundary conditions from D2-brane and the
related boundary conditions and vice versa has been possible in our recent work
by using 3-Lie bialgebra for BLG model with N = 8 supersymmetry. This could be
generalized for BL model with N = 6 by the concept of the 3-Leibniz bialgebra.
The 3-Lie bialgebra is an especial case of 3-Leibniz bialgebra, then more
comprehensive information will be obtained in this work. Consequently,
according to the correspondence of these 3-Leibniz bialgebras with Lie
bialgebras, we reduce to D2-brane such that with some restrictions on the gauge
field this D2-brane is related to the bosonic sector of an N = (4,4) WZW model
equipped with one 2-cocycle in its Lie bialgebra structure. Moreover, the
Basu-Harvey equation which is found by considering boundary conditions for BL
model containing Leibniz bialgebra structure is reduced to Nahm equation and
vice versa using this correspondence.


title: Broadband short term variability of the quasar PDS 456

abstract:
  We present a detailed analysis of a recent $500$ ks net exposure
\textit{Suzaku} observation, carried out in 2013, of the nearby ($z=0.184$)
luminous (L$_{\rm bol}\sim10^{47}$ erg s$^{-1}$) quasar PDS 456 in which the
X-ray flux was unusually low. The short term X-ray spectral variability has
been interpreted in terms of variable absorption and/or intrinsic continuum
changes. In the former scenario, the spectral variability is due to variable
covering factors of two regions of partially covering absorbers. We find that
these absorbers are characterised by an outflow velocity comparable to that of
the highly ionised wind, i.e. $\sim0.25$ c, at the $99.9\%$ $(3.26\sigma)$
confidence level. This suggests that the partially absorbing clouds may be the
denser clumpy part of the inhomogeneous wind. Following an obscuration event we
obtained a direct estimate of the size of the X-ray emitting region, to be not
larger than $20~R_{\rm g}$ in PDS 456.


title:
The luminosity dependence of quasar UV continuum slope: dust extinction
  scenario

abstract:
  We investigate the UV continuum slope $\alpha$ of a large quasar sample from
SDSS DR7. By using specific continuum windows, we build two samples at lower
($0.71<z<1.19$) and higher ($1.90<z<3.15$) redshifts, which correspond to the
continuum slopes at longer (NUV) and shorter (FUV) rest wavelength ranges
respectively. Overall, the average continuum slopes are $-0.36$ and $-0.51$ for
$\alpha_{\rm NUV}$ and $\alpha_{\rm FUV}$ with similar dispersions
$\sigma_{\alpha} \sim 0.5$. For both samples, we confirm the luminosity
dependence of the continuum slope, i.e., fainter quasars have redder spectra.
We further find that both $\alpha_{\rm NUV}$ and $\alpha_{\rm FUV}$ have a
common upper limit ($\sim 1/3$) which is almost independent of the quasar
luminosity $L_{\rm bol}$. This finding implies that the intrinsic quasar
continuum (or the bluest quasar), at any luminosity, obey the standard thin
disk model. We propose that the other quasars with redder $\alpha$ are caused
by the reddening from the dust {\it locally}. With this assumption, we employ
the dust extinction scenario to model the observed $L_{\rm bol}-\alpha$
relation. We find that, a typical value of $E(B-V)\sim0.1$ to $0.3$ mag
(depending on the types of extinction curve) of the quasar {\it local} dust is
enough to explain the discrepancy of $\alpha$ between the observation
($\sim-0.5$) and the standard accretion disk model prediction ($\sim 1/3$).


title: Population transfer driven by far-off-resonant fields

abstract:
  For a two-level system, it is believed that a far-off-resonant driving can
not help coherent population transfer between the states. In this work, we
propose a scheme to implement the coherent transfer with far-off-resonant
driving. The scheme works well with both constant driving and Gaussian driving.
The total time to finish population transfer is also minimized by optimizing
the detuning and coupling constants. We find that the scheme is sensitive to
spontaneous emission much more than dephasing. It might find potential
applications in X-ray quantum optics and population transfer in Rydberg atoms
as well.


title: Magnetic properties of ground-state mesons

abstract:
  Starting with the bag model a method for the study of the magnetic properties
(magnetic moments, magnetic dipole transition widths) of ground-state mesons is
developed. We calculate the M1 transition moments and use them subsequently to
estimate the corresponding decay widths. These are compared with experimental
data, where available, and with the results obtained in other approaches.
Finally, we give the predictions for the static magnetic moments of all
ground-state vector mesons including those containing heavy quarks. We have a
good agreement with experimental data for the M1 decay rates of light as well
as heavy mesons. Therefore, we expect our predictions for the static magnetic
properties (usual magnetic moments) to be of sufficiently high quality, too.


title:
HORACE: software for the analysis of data from single crystal
  spectroscopy experiments at time-of-flight neutron instruments

abstract:
  The HORACE suite of programs has been developed to work with large
multiple-measurement data sets collected from time-of-flight neutron
spectrometers equipped with arrays of position-sensitive detectors. The
software allows exploratory studies of the four dimensions of reciprocal space
and excitation energy to be undertaken, enabling multi-dimensional subsets to
be visualized, algebraically manipulated, and models for the scattering to
simulated or fitted to the data. The software is designed to be an extensible
framework, thus allowing user-customized operations to be performed on the
data. Examples of the use of its features are given for measurements exploring
the spin waves of the simple antiferromagnet RbMnF$_{3}$ and ferromagnetic
iron, and the phonons in URu$_{2}$Si$_{2}$.


title:
Random selection of factors preserves the correlation structure in a
  linear factor model to a high degree

abstract:
  In a very high-dimensional vector space, two randomly-chosen vectors are
almost orthogonal with high probability. Starting from this observation, we
develop a statistical factor model, the random factor model, in which factors
are chosen at random based on the random projection method. Randomness of
factors has the consequence that covariance matrix is well preserved in a
linear factor representation. It also enables derivation of probabilistic
bounds for the accuracy of the random factor representation of time-series,
their cross-correlations and covariances. As an application, we analyze
reproduction of time-series and their cross-correlation coefficients in the
well-diversified Russell 3,000 equity index.


title: CLAASIC: a Cortex-Inspired Hardware Accelerator

abstract:
  This work explores the feasibility of specialized hardware implementing the
Cortical Learning Algorithm (CLA) in order to fully exploit its inherent
advantages. This algorithm, which is inspired in the current understanding of
the mammalian neo-cortex, is the basis of the Hierarchical Temporal Memory
(HTM). In contrast to other machine learning (ML) approaches, the structure is
not application dependent and relies on fully unsupervised continuous learning.
We hypothesize that a hardware implementation will be able not only to extend
the already practical uses of these ideas to broader scenarios but also to
exploit the hardware-friendly CLA characteristics. The architecture proposed
will enable an unfeasible scalability for software solutions and will fully
capitalize on one of the many CLA advantages: low computational requirements
and reduced storage utilization. Compared to a state-of-the-art CLA software
implementation it could be possible to improve by 4 orders of magnitude in
performance and up to 8 orders of magnitude in energy efficiency. We propose to
use a packet-switched network to tackle this. The paper addresses the
fundamental issues of such an approach, proposing solutions to achieve scalable
solutions. We will analyze cost and performance when using well-known
architecture techniques and tools. The results obtained suggest that even with
CMOS technology, under constrained cost, it might be possible to implement a
large-scale system. We found that the proposed solutions enable a saving of 90%
of the original communication costs running either synthetic or realistic
workloads.


title: Lorentz and CPT violation in the Standard-Model Extension

abstract:
  Lorentz and CPT invariance are among the symmetries that can be investigated
with ultrahigh precision in subatomic physics. Being spacetime symmetries,
Lorentz and CPT invariance can be violated by minuscule amounts in many
theoretical approaches to underlying physics that involve novel spacetime
concepts, such as quantized versions of gravity. Regardless of the underlying
mechanism, the low-energy effects of such violations are expected to be
governed by effective field theory. This talk provides a survey of this idea
and includes an overview of experimental efforts in the field.


title: Decoding Interleaved Gabidulin Codes using Alekhnovich's Algorithm

abstract:
  We prove that Alekhnovich's algorithm can be used for row reduction of skew
polynomial matrices. This yields an $O(\ell^3 n^{(\omega+1)/2} \log(n))$
decoding algorithm for $\ell$-Interleaved Gabidulin codes of length $n$, where
$\omega$ is the matrix multiplication exponent, improving in the exponent of
$n$ compared to previous results.


title:
Thermal and quantum fluctuations of confined Bose-Einstein condensate
  beyond the Bogoliubov approximation

abstract:
  The formulation for zero mode of a Bose-Einstein condensate beyond the
Bogoliubov approximation at zero temperature [Y.Nakamura et al., Phys. Rev. A
89, 013613 (2014)] is extended to finite temperature. Both thermal and quantum
fluctuations are considered in a manner consistent with a concept of
spontaneous symmetry breakdown for a finite-size system. Therefore, we need a
proper treatment of the zero mode operators, which invoke non-trivial
enhancements in depletion condensate and thermodynamical quantities such as the
specific heat. The enhancements are visible in the weak interaction case. Our
approach reproduces the results of a homogeneous system in the Bogoliubov
approximation in a large particle number limit.


title:
Experimental investigation of the stronger uncertainty relations for all
  incompatible observables

abstract:
  The Heisenberg-Robertson uncertainty relation quantitatively expresses the
impossibility of jointly sharp preparation of incompatible observables. However
it does not capture the concept of incompatible observables because it can be
trivial even for two incompatible observables. We experimentally demonstrate
the new stronger uncertainty relations proposed by Maccone and Pati [Phys. Rev.
Lett. 113, 260401 (2014)] relating on that sum of variances are valid in a
state-dependent manner and the lower bound is guaranteed to be nontrivial for
two observables being incompatible on the state of the system being measured.
The behaviour we find agrees with the predictions of quantum theory and obeys
the new uncertainty relations even for the special states which trivialize
Heisenberg-Robertson relation. We realize a direct measurement model and give
the first experimental investigation of the strengthened relations.


title: Finite groups whose commuting graphs are integral

abstract:
  A finite non-abelian group $G$ is called commuting integral if the commuting
graph of $G$ is integral. In this paper, we show that a finite group is
commuting integral if its central factor is isomorphic to ${\mathbb{Z}}_p
\times {\mathbb{Z}}_p$ or $D_{2m}$, where $p$ is any prime integer and $D_{2m}$
is the dihedral group of order $2m$.


title: A declarative Language for Rapid Business Development

abstract:
  The motivation for ZoomBA are domain specific languages (DSL) like VERILOG,
VHDL, Spice. DSL for Software testing is not a new idea, many commercial tools
like Silk Suite use them, while Selenese, the DSL for Selenium IDE [6] is open
source. ZoomBA is a functionally motivated, embeddable, Turing Complete
language. It's philosophy is to expose the existing Java echo system in a
declarative fashion for the purpose of System Integration and software
validation. By design ZoomBA script size is meagre compared to Python or even
to Scala for business automation problems. Bayestree uses ZoomBA for system
integration/adapter/data manipulation purposes.


title:
Collapse of a self-gravitating Bose-Einstein condensate with attractive
  self-interaction

abstract:
  We study the collapse of a self-gravitating Bose-Einstein condensate with
attractive self-interaction. Equilibrium states in which the gravitational
attraction and the attraction due to the self-interaction are counterbalanced
by the quantum pressure exist only below a maximum mass $M_{\rm
max}=1.012\hbar/\sqrt{Gm|a_s|}$ where $a_s<0$ is the scattering length of the
bosons and $m$ is their mass. For $M>M_{\rm max}$ the system is expected to
collapse and form a black hole. We study the collapse dynamics by making a
Gaussian ansatz for the wave function. We find that the collapse time scales as
$(M/M_{\rm max}-1)^{-1/4}$ for $M\rightarrow M_{\rm max}^+$ and as $M^{-1/2}$
for $M\gg M_{\rm max}$. We apply our results to standard axions with mass
$m=10^{-4}\, {\rm eV}/c^2$ and scattering length $a_s=-5.8\times 10^{-53}\,
{\rm m}$ for which $M_{\rm max}=6.5\times 10^{-14}M_{\odot}$ and $R=3.3\times
10^{-4}\, R_{\odot}$. We confirm our previous claim that bosons with attractive
self-interaction, such as standard axions, may form low mass stars but cannot
form dark matter halos of relevant mass and size. These mini axions stars could
be the constituents of dark matter. They can collapse into mini black holes of
mass $\sim 10^{-14}\, M_{\odot}$ in a few hours. In that case, dark matter
halos would be made of mini black holes. We also apply our results to
ultralight axions with mass $m=1.93\times 10^{-20}\, {\rm eV}/c^2$ and
scattering length $a_s=-8.29\times 10^{-60}\, {\rm fm}$ for which $M_{\rm
max}=0.39\times 10^6\, M_{\odot}$ and $R=33\, {\rm pc}$. These ultralight
axions could cluster into dark matter halos. Axionic dark matter halos with
attractive self-interaction can collapse into supermassive black holes of mass
$\sim 10^{6}\, M_{\odot}$ in about one million years.


title:
Localized State in a Two-Dimensional Quantum Walk on a Disordered
  Lattice

abstract:
  We realize a pair of simultaneous ten-step one-dimensional quantum walks with
two walkers sharing coins, which we prove is analogous to the ten-step
two-dimensional quantum walk with a single walker holding a four-dimensional
coin. Our experiment demonstrates a ten-step quantum walk over an 11x11
two-dimensional lattice with a line defect, thereby realizing a localized
walker state.


title: The convective stability of fully stratified baroclinic discs

abstract:
  We examine the convective stability of hydrodynamic discs with full
stratification in the local approximation and in the presence of thermal
diffusion (or relaxation). Various branches of the relevant axisymmetric
dispersion relation derived by Urpin (2003) are discussed. We find that when
the vertical Richardson number is larger than or equal to the radial one (i.e.
$|Ri_z|\geq|Ri_x|$) and wavenumbers are comparable (i.e. $|k_x|\sim|k_z|$) the
disc becomes unstable, even in the presence of radial and vertical
stratifications with $Ri_x>0$ and $Ri_z>0$. The origin of this resides in an
hybrid radial-vertical Richardson number. We propose an equilibrium profile
with temperature depending on the radial and vertical coordinates and with
$Ri_z>0$ for which this destabilization mechanism occurs. We notice as well
that the dispersion relation of the "convective overstability" is the branch of
the one here discussed in the limit $|k_z|\gg|k_x|$ (i. e. two-dimensional
disc).


title:
Local Binary Pattern for Word Spotting in Handwritten Historical
  Document

abstract:
  Digital libraries store images which can be highly degraded and to index this
kind of images we resort to word spot- ting as our information retrieval
system. Information retrieval for handwritten document images is more
challenging due to the difficulties in complex layout analysis, large
variations of writing styles, and degradation or low quality of historical
manuscripts. This paper presents a simple innovative learning-free method for
word spotting from large scale historical documents combining Local Binary
Pattern (LBP) and spatial sampling. This method offers three advantages:
firstly, it operates in completely learning free paradigm which is very
different from unsupervised learning methods, secondly, the computational time
is significantly low because of the LBP features which are very fast to
compute, and thirdly, the method can be used in scenarios where annotations are
not available. Finally we compare the results of our proposed retrieval method
with the other methods in the literature.


title: 3D Massive MIMO Systems: Modeling and Performance Analysis

abstract:
  Multiple-input-multiple-output (MIMO) systems of current LTE releases are
capable of adaptation in the azimuth only. Recently, the trend is to enhance
system performance by exploiting the channel's degrees of freedom in the
elevation, which necessitates the characterization of 3D channels. We present
an information-theoretic channel model for MIMO systems that supports the
elevation dimension. The model is based on the principle of maximum entropy,
which enables us to determine the distribution of the channel matrix consistent
with the prior information on the angles. Based on this model, we provide
analytical expression for the cumulative density function (CDF) of the mutual
information (MI) for systems with a single receive and finite number of
transmit antennas in the general signal-to-interference-plus-noise-ratio (SINR)
regime. The result is extended to systems with finite receive antennas in the
low SINR regime. A Gaussian approximation to the asymptotic behavior of MI
distribution is derived for the large number of transmit antennas and paths
regime. We corroborate our analysis with simulations that study the performance
gains realizable through meticulous selection of the transmit antenna downtilt
angles, confirming the potential of elevation beamforming to enhance system
performance. The results are directly applicable to the analysis of 5G
3D-Massive MIMO-systems.


title: Control and manipulation of a magnetic skyrmionium in nanostructures

abstract:
  A magnetic skyrmionium is a nontopological soliton, which has a doughnut-like
out-of-plane spin texture in thin films, and can be phenomenologically viewed
as a coalition of two topological magnetic skyrmions with opposite topological
numbers. Due to its zero topological number ($Q=0$) and doughnut-like
structure, the skyrmionium has its distinctive characteristics as compared to
the skyrmion with $Q=\pm 1$. Here we systematically study the generation,
manipulation and motion of a skyrmionium in ultrathin magnetic nanostructures
by applying a magnetic field or a spin-polarized current. It is found that the
skyrmionium moves faster than the skyrmion when they are driven by the
out-of-plane current, and their velocity difference is proportional to the
driving force. However, the skyrmionium and skyrmion exhibit an identical
current-velocity relation when they are driven by the in-plane current. It is
also found that a moving skyrmionium is less deformed in the current-in-plane
geometry compared with the skyrmionum in the current-perpendicular-to-plane
geometry. Furthermore we demonstrate the transformation of a skyrmionium with
$Q=0$ into two skyrmions with $Q=+1$ in a nanotrack driven by a spin-polarized
current, which can be seen as the unzipping process of a skyrmionium. We
illustrate the energy and spin structure variations during the skyrmionium
unzipping process, where linear relations between the spin structure and
energies are found. These results could have technological implications in the
emerging field of skyrmionics.


title:
A Tutorial on Libra: R package for the Linearized Bregman Algorithm in
  High Dimensional Statistics

abstract:
  The R package, Libra, stands for the LInearized BRegman Al- gorithm in high
dimensional statistics. The Linearized Bregman Algorithm is a simple iterative
procedure to generate sparse regularization paths of model estimation, which
are rstly discovered in applied mathematics for image restoration and
particularly suitable for parallel implementation in large scale problems. The
limit of such an algorithm is a sparsity-restricted gradient descent ow, called
the Inverse Scale Space, evolving along a par- simonious path of sparse models
from the null model to over tting ones. In sparse linear regression, the
dynamics with early stopping regularization can provably meet the unbiased
Oracle estimator under nearly the same condition as LASSO, while the latter is
biased. Despite their successful applications, statistical consistency theory
of such dynamical algorithms remains largely open except for some recent
progress on linear regression. In this tutorial, algorithmic implementations in
the package are discussed for several widely used sparse models in statistics,
including linear regression, logistic regres- sion, and several graphical
models (Gaussian, Ising, and Potts). Besides the simulation examples, various
application cases are demonstrated, with real world datasets from diabetes,
publications of COPSS award winners, as well as social networks of two Chinese
classic novels, Journey to the West and Dream of the Red Chamber.


title:
Hi-GAL, the Herschel infrared Galactic Plane Survey: photometric maps
  and compact source catalogues. First data release for Inner Milky Way:
  +68{\deg}> l > -70{\deg}

abstract:
  (Abridged) We present the first public release of high-quality data products
(DR1) from Hi-GAL, the {\em Herschel} infrared Galactic Plane Survey. Hi-GAL is
the keystone of a suite of continuum Galactic Plane surveys from the near-IR to
the radio, and covers five wavebands at 70, 160, 250, 350 and 500 micron,
encompassing the peak of the spectral energy distribution of cold dust for 8 <
T < 50K. This first Hi-GAL data release covers the inner Milky Way in the
longitude range 68{\deg} > l > -70{\deg} in a |b|<1{\deg} latitude strip.
Photometric maps have been produced with the ROMAGAL pipeline, that optimally
capitalizes on the excellent sensitivity and stability of the bolometer arrays
of the {\em Herschel} PACS and SPIRE photometric cameras, to deliver images of
exquisite quality and dynamical range, absolutely calibrated with {\em Planck}
and {\em IRAS}, and recovering extended emission at all wavelengths and all
spatial scales. The compact source catalogues have been generated with the
CuTEx algorithm, specifically developed to optimize source detection and
extraction in the extreme conditions of intense and spatially varying
background that are found in the Galactic Plane in the thermal infrared. Hi-GAL
DR1 images will be accessible via a dedicated web-based image cutout service.
The DR1 Compact Source Catalogues are delivered as single-band photometric
lists containing, in addition to source position, peak and integrated flux and
source sizes, a variety of parameters useful to assess the quality and
reliability of the extracted sources, caveats and hints to help this assessment
are provided. Flux completeness limits in all bands are determined from
extensive synthetic source experiments and depend on the specific line of sight
along the Galactic Plane. Hi-GAL DR1 catalogues contain 123210, 308509, 280685,
160972 and 85460 compact sources in the five bands, respectively.


title: Magnetoresistance and Shubnikov-de Hass oscillation in YSb

abstract:
  YSb crystals are grown and the transport properties under magnetic field are
measured. The resistivity exhibits metallic behavior under zero magnetic field
and the low temperature resistivity shows a clear upturn once a moderate
magnetic field is applied. The upturn is greatly enhanced by increasing
magnetic field, finally resulting in a metal-to-insulator-like transition. With
temperature further decreased, a resistivity plateau emerges after the
insulator-like regime. At low temperature (2.5 K) and high field (14 T), the
transverse magnetoresistance (MR) is quite large (3.47 $\times 10^4\%$ ). In
addition, Shubnikov-de Haas (SdH) oscillation has also been observed in YSb.
Periodic behavior of the oscillation amplitude reveals the related information
about Fermi surface and two major oscillation frequencies can be obtained from
the FFT spectra of the oscillations. The trivial Berry phase extracted from SdH
oscillation, band structure revealed by angle-resolved photoemission
spectroscopy (ARPES) and first-principles calculations demonstrate that YSb is
a topologically trivial material.


title:
Comments on "Characteristic matrix of covering and its application to
  Boolean matrix decomposition[Information Sciences 263(1), 186-197, 2014]"

abstract:
  In this note, we show some improvements for Theorem 7 and Example 8 in
Shiping Wang[Information Sciences 263(1), 186-197, 2014]. Concretely, we study
further the sixth lower and upper approximations of sets for covering
approximation spaces. Furthermore, we present the sixth dual lower and upper
approximations of sets for covering approximation spaces. We also construct the
sixth dual lower and upper approximations of sets from the view of matrix.
Throughout, we use the same notations as Shiping Wang[Information Sciences
263(1), 186-197, 2014].


title: Parallel impurity dynamics in the TJ-II stellarator

abstract:
  We review in a tutorial fashion some of the causes of impurity density
variations along field lines and radial impurity transport in the moment
approach framework. An explicit and compact form of the parallel inertia force
valid for arbitrary toroidal geometry and magnetic coordinates is derived and
shown to be non-negligible for typical TJ-II plasma conditions. In the second
part of the article, we apply the fluid model including main ion-impurity
friction and inertia to observations of asymmetric emissivity patterns in
neutral beam heated plasmas of the TJ-II stellarator. The model is able to
explain qualitatively several features of the radiation asymmetry, both in
stationary and transient conditions, based on the calculated in-surface
variations of the impurity density.


title:
Using Binoculars for Fast Exploration and Map Construction in Chordal
  Graphs and Extensions

abstract:
  We investigate the exploration and mapping of anonymous graphs by a mobile
agent. It is long known that, without global information about the graph, it is
not possible to make the agent halt after the exploration except if the graph
is a tree. We therefore endow the agent with binoculars, a sensing device that
can show the local structure of the environment at a constant distance of the
agent's current location and investigate networks that can be efficiently
explored in this setting.
  In the case of trees, the exploration without binoculars is fast (i.e. using
a DFS traversal of the graph, there is a number of moves linear in the number
of nodes). We consider here the family of Weetman graphs that is a
generalization of the standard family of chordal graphs and present a new
deterministic algorithm that realizes Exploration of any Weetman graph, without
knowledge of size or diameter and for any port numbering. The number of moves
is linear in the number of nodes, despite the fact that Weetman graphs are not
sparse, some having a number of edges that is quadratic in the number of nodes.
  At the end of the Exploration, the agent has also computed a map of the
anonymous graph.


title: Phase transitions in the Hubbard model for the bismuth nickelate

abstract:
  We study low temperature properties of the Hubbard model for the bismuth
nickelate, where degenerate orbitals in the nickel ions and a single orbital in
the bismuth ions are taken into account, combining dynamical mean-field theory
with the continuous-time quantum Monte Carlo method. We discuss the effect of
the attractive interactions to mimic the valence skipping phenomenon in the
bismuth ions. We demonstrate how the charge and magnetically ordered states are
stable against thermal fluctuations. It is furthermore clarified that the
ferromagnetically ordered and orbital ordered states are stabilized due to the
presence of the orbital degeneracy at low temperatures. The crossover between
metallic and insulating states is also discussed.


title: Feynman rules for Gauss's law

abstract:
  I work on a set of Feynman rules that were derived in order to incorporate
the constraint of Gauss's law in the perturbation expansion of gauge field
theories and calculate the interaction energy of two static sources. The
constraint is implemented via a Lagrange multiplier field, $\lambda$, which, in
the case of the non-Abelian theory, develops a radiatively generated effective
potential term. After analysing the contributions of various solutions for
$\lambda$, the confining properties and the various phases of the theory are
discussed.


title:
Robust Picosecond writing of a Layered Antiferromagnet by Staggered
  Spin-Orbit-Fields

abstract:
  Ultrafast electrical switching by current-induced staggered spin-orbit
fields, with minimal risk of overshoot, is shown in layered easy-plane
antiferromagnets with basal-plane biaxial anisotropy. The reliable switching is
due to the field-like torque, relaxing stringent requirements with respect to
precision in the time-duration of the excitation pulse. We investigate the
switching characteristics as a function of the spin-orbit field strength, pulse
duration, pulse rise and fall time and damping by atomistic spin dynamics
simulations and an effective equation of motion for the antiferromagnetic
order-parameter. The condition, determining the critical spin-orbit field
strength for switching is determined and we go on to show that robust
picosecond writing is possible at feasible current magnitudes.


title:
A Novel Analytic Approach to Model Line Edge Roughness using Stochastic
  Exposure Distribution in Electron-beam Lithography

abstract:
  The line edge roughness (LER) becomes a issue of e-beam lithography when
feature size is reduced into nanometers. Therefore, minimizing the LER is a
important method to increase the density of circuit patterns. One of the
possible ways is through simulation. The stochastic exposure distributions in
the resist is generated by the Monte Carlo simulation. In addition a resist
development simulation needs to be carried out. Although there are several ways
to simulate or estimate LER but none of them can reveal as much the inner
relationship between LER and different parameters as theocratical analysing
methods can do. In this paper, a new approach to analytically derive the LER
based on the statistical exposure, is described. Our approach is based on
analytic model of stochastic exposure distribution, deriving standard deviation
of exposure and analyzing the variance of edge location after development. Even
though it may not be a complete modeling of LER, it can still show some strong
relationship between LER and some inner parameters.


title:
Unexpected aspects of strain relaxation and compensation in InGaAs
  metamorphic structures grown by MOVPE

abstract:
  We present a selection of stack designs for MOVPE grown InxGa1-xAs
metamorphic buffer layers following various convex-down compositional
continuous gradients of the In content, showing that defect generation and
strain can be managed in a variety of ways, some rather unexpected (and
unreported). Indeed, we observe that it is possible to grow surprisingly thick
tensile strained layers on metamorphic substrates, without significant
relaxation and defect generation. We believe our findings give significant
insights to the investigation of strain, relaxation and defect distribution in
metamorphic buffer design, so to obtain properly engineered/tailored structures
(the most successful ones already finding applications in device growth).


title:
Jansen-MIDAS: a multi-level photomicrograph segmentation software based
  on isotropic undecimated wavelets

abstract:
  Image segmentation, the process of separating the elements within an image,
is frequently used for obtaining information from photomicrographs. However,
segmentation methods should be used with reservations: incorrect segmentation
can mislead when interpreting regions of interest (ROI), thus decreasing the
success rate of additional procedures. Multi-Level Starlet Segmentation (MLSS)
and Multi-Level Starlet Optimal Segmentation (MLSOS) were developed to address
the photomicrograph segmentation deficiency on general tools. These methods
gave rise to Jansen-MIDAS, an open-source software which a scientist can use to
obtain a multi-level threshold segmentation of his/hers photomicrographs. This
software is presented in two versions: a text-based version, for GNU Octave,
and a graphical user interface (GUI) version, for MathWorks MATLAB. It can be
used to process several types of images, becoming a reliable alternative to the
scientist.


title: B\'ezout domains and lattice-valued modules

abstract:
  Let B be a commutative B\'ezout domain B and let MSpec(B) be the maximal
spectrum of B. We obtain a Feferman-Vaught type theorem for the class of
B-modules. We analyse the definable sets in terms, on one hand, of the
definable sets in the classes of modules over the localizations of B by the
maximal ideals of B, and on the other hand, of the constructible subsets of
MSpec(B). When B has good factorization, it allows us to derive decidability
results for the class B-modules, in particular when B is the ring of algebraic
integers or its intersection with real numbers or p-adic numbers.


title:
Reconstructing a website's lost past: Methodological issues concerning
  the history of www.unibo.it

abstract:
  This paper describes how born digital primary sources could be used to
reconstruct the recent history of scientific institutions. The case study is an
analysis of the first 25 years online of the University of Bologna. The focus
of this work is primarily methodological: several different issues are
presented, starting with the fact that the University of Bologna website has
been excluded for thirteen years from the Internet Archive's Wayback Machine,
and possible solutions are proposed and applied. The article is organised in
three parts: in the first one, some of the fundamental concepts on web archives
and the preservation of born digital sources are introduced. Then the
reconstruction of the University of Bologna web's past is presented. Finally
the future of this research is described, presenting a specific case study in
which the historian's craft will be challenged by a completely different issue,
namely the large amount of data available in the university digital library.


title: String coupling constant seems to be 1

abstract:
  We present a reasoning that the string coupling constant should be 1 from the
assumption that the area spectrum derived from loop quantum gravity must be
equal to the area spectrum calculated from "stringy differential geometry." To
this end, we will use the loop quantum gravity area spectrum constructions
proposed by Brian Kong and us, and stringy differential geometry based on
double field theory recently proposed by Imtak Jeon, Kanghoon Lee and
Jeong-Hyuck Park.


title: Charting an Intent Driven Network

abstract:
  The current strong divide between applications and the network control plane
is desirable for many reasons; but a downside is that the network is kept in
the dark regarding the ultimate purposes and intentions of applications and, as
a result, is unable to optimize for these. An alternative approach, explored in
this paper, is for applications to declare to the network their abstract
intents and assumptions; e.g. "this is a Tweet", or "this application will run
within a local domain". Such an enriched semantic has the potential to enable
the network better to fulfill application intent, while also helping optimize
network resource usage across applications. We refer to this approach as
'intent driven networking' (IDN), and we sketch an incrementally-deployable
design to serve as a stepping stone towards a practical realization of the IDN
concept within today's Internet.


title:
Optimal programmable unambiguous discriminator between two unknown
  latitudinal states

abstract:
  Two unknown states can be unambiguously distinguished by a universal
programmable discriminator, which has been widely discussed in previous works
and the optimal solution has also been obtained. In this paper, we investigate
the programmable unambiguous discriminator between two unknown "latitudinal"
states, which lie in a subspace of the total state space. By equivalence of
unknown pure states to known average mixed states, the optimal solution for
this problem is systematically derived, and the analytical success
probabilities for the optimal unambiguous discrimination are obtained. It is
beyond one's expectation that the optimal setting for the programmable
unambiguous discrimination between two unknown "latitudinal" states is the same
as that for the universal ones. The results in this work can be used for the
realization of the programmable discriminator in laboratory.


title: Some results on the computing of Tukey's halfspace medain

abstract:
  Depth of the Tukey median is investigated for empirical distributions. A
sharper upper bound is provided for this value for data sets in general
position. This bound is lower than the existing one in the literature, and more
importantly derived under the \emph{fixed} sample size practical scenario.
Several results obtained in this paper are interesting theoretically and useful
as well to reduce the computational burden of the Tukey median practically when
$p$ is large relative to large $n$.


title: Low entropy in graphene through the Co-C system

abstract:
  Uniform, mostly single-layer graphene with enhanced stability is demonstrated
over Co film. The polycrystalline Co film deposited on a SiO2/Si substrate
gives a continuous graphene layer that is easily transferred without the aid of
any polymeric support, but preserving the material quality, as evidenced by
Raman analysis. Great stability to the damaging action of the laser beam, as
compared to the Cu-grown material is also observed. The better structural and
electrical properties of the material are interpreted in terms of
thermodynamics of the cooling-down process. It is suggested that the reduction
in entropy, due annihilation of vacancies caused by C atoms precipitating
during cooling, directly depends on the activation energy of C solubility into
Co, which is considerably high, due to Co magnetic ordering at the process
temperature. Our work expands the possibility of synthesizing single-layer
graphene keeping into account the thermodynamics of various C-metal systems.


title: Super-oscillating Electron Wave Functions with Sub-diffraction Spots

abstract:
  Almost one and a half centuries ago, Ernst Abbe [1] and shortly after Lord
Rayleigh [2] showed that when an optical lens is illuminated by a plane wave, a
diffraction-limited spot with a radius 0.61*lambda/sin(alpha) is obtained,
where lambda is the wavelength and alpha is the semi-angle of the beam's
convergence cone. However, spots with much smaller features can be obtained at
the focal plane when the lens is illuminated by an appropriately structured
beam. Whereas this concept is known for light beam, here, we show how to
realize it for massive-particle wave function of a free electron. We
experimentally demonstrate an electron central spot of radius 106 pm, which is
more than two times smaller than the diffraction limit of the experimental
setup used. In addition, we demonstrate that this central spot can be
structured by adding orbital angular momentum to it. The resulting
super-oscillating vortex beam has a smaller dark core with respect to the
regular vortex beam. This new family of electron beams having hot-spots with
arbitrarily small features and tailored structure can be useful for studying
electron-matter interactions with sub-atomic resolution.