title:
QCD Factorization for $B \to \pi\pi\ell\nu$ Decays at Large Dipion
  Masses

abstract:
  We introduce a factorization formula for semi-leptonic $b \to u$ transitions
in the exclusive decay mode $B^- \to \pi^+\pi^-\ell^-\bar\nu_\ell$ in the limit
of large pion energies and large dipion invariant mass. One contribution can be
described in terms of a universal $B \to \pi$ form factor and the convolution
of a short-distance kernel $T^{\rm I}$ with the respective light-cone
distribution amplitudes (LCDAs) of the positively charged pion. The second
contribution, at leading power, completely factorizes, with a short-distance
kernel $T^{\rm II}$ convoluted with the leading-twist LCDAs for both pions and
the $B$-meson. We calculate the leading contributions to the short-distance
kernels $T^{\rm I}$ and $T^{\rm II}$ in fixed-order perturbation theory, and
discuss the approximate relations among the resulting $B \to \pi\pi$
partial-wave form factors. Our results provide useful theoretical constraints
for phenomenological models that aim to analyze the complete $B \to \pi\pi
\ell\nu$ phase space.


title: Hybrid surface waves in two-dimensional Rashba-Dresselhaus materials

abstract:
  We address the electromagnetic properties of two-dimensional electron gas
confined by a dielectric environment in the presence of both Rashba and
Dresselhaus spin-orbit interactions. It is demonstrated that off-diagonal
components of the conductivity tensor resulting from a delicate interplay
between Rashba and Dresselhaus couplings lead to the hybridization of
transverse electric and transverse magnetic surface electromagnetic modes
localized at the interface. We show that the characteristics of these hybrid
surface waves can be controlled by additional intense external off-resonant
coherent pumping.


title:
On the Hierarchical Preconditioning of the PMCHWT Integral Equation on
  Simply and Multiply Connected Geometries

abstract:
  We present a hierarchical basis preconditioning strategy for the
Poggio-Miller-Chang-Harrington-Wu-Tsai (PMCHWT) integral equation considering
both simply and multiply connected geometries.To this end, we first consider
the direct application of hierarchical basis preconditioners, developed for the
Electric Field Integral Equation (EFIE), to the PMCHWT. It is notably found
that, whereas for the EFIE a diagonal preconditioner can be used for obtaining
the hierarchical basis scaling factors, this strategy is catastrophic in the
case of the PMCHWT since it leads to a severly ill-conditioned PMCHWT system in
the case of multiply connected geometries. We then proceed to a theoretical
analysis of the effect of hierarchical bases on the PMCHWT operator for which
we obtain the correct scaling factors and a provably effective preconditioner
for both low frequencies and mesh refinements. Numerical results will
corroborate the theory and show the effectiveness of our approach.


title:
A primordial origin for molecular oxygen in comets: A chemical kinetics
  study of the formation and survival of O$_2$ ice from clouds to disks

abstract:
  Molecular oxygen has been confirmed as the fourth most abundant molecule in
cometary material O$_2$/H$_2$O $\sim 4$ %) and is thought to have a primordial
nature, i.e., coming from the interstellar cloud from which our solar system
was formed. However, interstellar O$_2$ gas is notoriously difficult to detect
and has only been observed in one potential precursor of a solar-like system.
Here, the chemical and physical origin of O$_2$ in comets is investigated using
sophisticated astrochemical models. Three origins are considered: i) in dark
clouds, ii) during forming protostellar disks, and iii) during luminosity
outbursts in disks. The dark cloud models show that reproduction of the
observed abundance of O$_2$ and related species in comet 67P/C-G requires a low
H/O ratio facilitated by a high total density ($\geq 10^5$ cm$^{-3}$), and a
moderate cosmic ray ionisation rate ($\leq 10^{-16}$ s$^{-1}$) while a
temperature of 20 K, slightly higher than the typical temperatures found in
dark clouds, also enhances the production of O$_2$. Disk models show that O$_2$
can only be formed in the gas phase in intermediate disk layers, and cannot
explain the strong correlation between O$_2$ and H$_2$O in comet 67P/C-G
together with the weak correlation between other volatiles and H$_2$O. However,
primordial O$_2$ ice can survive transport into the comet-forming regions of
disks. Taken together, these models favour a dark cloud (or "primordial")
origin for O$_2$ in comets, albeit for dark clouds which are warmer and denser
than those usually considered as solar system progenitors.


title: Ergodic boundary representations

abstract:
  We prove a von Neumann type ergodic theorem for averages of unitary operators
arising from the Furstenberg-Poisson boundary representation (the quasi-regular
representation) of any lattice in a non-compact connected semisimple Lie group
with finite center.


title:
Single-photon emitters based on NIR colour centres in diamond coupled
  with solid immersion lenses

abstract:
  Single-photon sources represent a key enabling technology in quantum optics,
and single colour centres in diamond are a promising platform to serve this
purpose, due to their high quantum efficiency and photostability at room
temperature. The widely studied nitrogen vacancy centres are characterized by
several limitations, thus other defects have recently been considered, with a
specific focus of centres emitting in the Near Infra-Red. In the present work,
we report on the coupling of native near-infrared-emitting centres in
high-quality single crystal diamond with Solid Immersion Lens structures
fabricated by Focused Ion Beam lithography. The reported improvements in terms
of light collection efficiency make the proposed system an ideal platform for
the development of single-photon emitters with appealing photophysical and
spectral properties.


title:
Magnetar-like X-ray Bursts from a Rotation Powered Pulsar, PSR
  J1119-6127

abstract:
  Two energetic hard X-ray bursts have recently triggered the Fermi and Swift
space observatories from the rotation powered pulsar, PSR J1119-6127. We have
performed in depth spectral and temporal analyses of these two events. Our
extensive searches in both observatory data for lower luminosity bursts
uncovered 10 additional events from the source. We report here on the timing
and energetics of the 12 bursts from PSR J1119-6127 during its burst active
phase of 2016 July 26 and 28. We also found a spectral softer X-ray flux
enhancement in a post burst episode, which shows evidence of cooling. We
discuss here the implications of these results on the nature of this unusual
high-field radio pulsar, which firmly place it within the typical magnetar
population.


title:
A 3-dimensional interdigitated electrode geometry for the enhancement of
  charge collection efficiency in diamond detectors

abstract:
  In this work, a single crystal CVD diamond film with a novel
three-dimensional (3D) interdigitated electrode geometry has been fabricated
with the Reactive Ion Etching (RIE) technique in order to increase the charge
collection efficiency (CCE) with respect to that obtained by standard
superficial electrodes. The geometrical arrangement of the electric field lines
due to the 3D patterning of the electrodes results in a shorter travel path for
the excess charge carriers, thus contributing to a more efficient charge
collection mech-anism. The CCE of the device was mapped by means of the Ion
Beam Induced Charge (IBIC) technique. A 1 MeV proton micro-beam was raster
scanned over the active area of the diamond detector under different bias
voltage conditions, enabling to probe the charge transport properties of the
detector up to a depth of 8 {\mu}m below the sample surface. The experimental
results, supported by the numerical simulations, show a significant improvement
in the 3D-detector performance (i.e. CCE, energy resolution, extension of the
active area) if compared with the results obtained by standard surface metallic
electrodes.


title: Multi-photon absorption in optical gratings for matter waves

abstract:
  We present a theory for the diffraction of large molecules or nanoparticles
at a standing light wave. Such particles can act as a genuine photon absorbers
due to their numerous internal degrees of freedom effecting fast internal
energy conversion. Our theory incorporates the interplay of three light-induced
properties: the coherent phase modulation due to the dipole interaction, a
non-unitary absorption-induced amplitude modulation described as a generalized
measurement, and a coherent recoil splitting that resembles a quantum random
walk in steps of the photon momentum. We discuss how these effects show up in
near-field and far-field interference schemes, and we confirm our effective
description by a dynamic evaluation of the grating interaction, which accounts
for the internal states.


title: Velocity, acceleration and gravity in Einstein's relativity

abstract:
  Einstein's relativity theory demands that all meaningful physical objects
should be defined covariantly, i.e. in a coordinate independent way. Concepts
of relative velocity, acceleration, gravity acceleration and gravity potential
are fundamental in Newton's theory and they are imprinted in everyone's
physical intuition. Unfortunately, relativistic definitions of them are not
commonly known or appreciated. Every now and then some confused authors use
wrong, non-covariant, definitions of velocity, acceleration and gravity, based
on their vague Newtonian intuitions and hidden in a superficial, often purely
semantic, relativistic disguise. A recent example of such a confusion (Gorkavyi
& Vasilkov, 2016) is discussed at the end of this Note.


title: Gapped spectrum in pair-superfluid bosons

abstract:
  We study the ground state of a bilayer system of dipolar bosons with dipoles
oriented by an external field perpendicularly to the two parallel planes. By
decreasing the interlayer distance, for a fixed value of the strength of the
dipolar interaction, the system undergoes a quantum phase transition from an
atomic to a pair superfluid. We investigate the excitation spectrum across this
transition by using microscopic approaches. Quantum Monte Carlo methods are
employed to obtain the static structure factors and intermediate scattering
functions in imaginary time. The dynamic response is calculated using both the
correlated basis functions (CBF) method and the approximate inversion of the
Laplace transform of the quantum Monte Carlo imaginary time data. In the atomic
phase, both density and spin excitations are gapless. However, in the
pair-superfluid phase a gap opens in the excitation energy of the spin mode.
For small separation between layers, the minimal spin excitation energy equals
the binding energy of a dimer and is twice the gap value.


title:
Sympathy for the Details: Dense Trajectories and Hybrid Classification
  Architectures for Action Recognition

abstract:
  Action recognition in videos is a challenging task due to the complexity of
the spatio-temporal patterns to model and the difficulty to acquire and learn
on large quantities of video data. Deep learning, although a breakthrough for
image classification and showing promise for videos, has still not clearly
superseded action recognition methods using hand-crafted features, even when
training on massive datasets. In this paper, we introduce hybrid video
classification architectures based on carefully designed unsupervised
representations of hand-crafted spatio-temporal features classified by
supervised deep networks. As we show in our experiments on five popular
benchmarks for action recognition, our hybrid model combines the best of both
worlds: it is data efficient (trained on 150 to 10000 short clips) and yet
improves significantly on the state of the art, including recent deep models
trained on millions of manually labelled images and videos.


title:
Time-dependent solutions for a stochastic model of gene expression with
  molecule production in the form of a compound Poisson process

abstract:
  We study a stochastic model of gene expression, in which protein production
has a form of random bursts whose size distribution is arbitrary, whereas
protein decay is a first-order reaction. We find exact analytical expressions
for the time evolution of the cumulant-generating function for the most general
case when both the burst size probability distribution and the model parameters
depend on time in an arbitrary (e.g. oscillatory) manner, and for arbitrary
initial conditions. We show that in the case of periodic external activation
and constant protein degradation rate, the response of the gene is analogous to
the RC low-pass filter, where slow oscillations of the external driving have a
greater effect on gene expression than the fast ones. We also demonstrate that
the $n$-th cumulant of the protein number distribution depends on the $n$-th
moment of the burst size distribution. We use these results to show that
different measures of noise (coefficient of variation, Fano factor, fractional
change of variance) may vary in time in a different manner. Therefore, any
biological hypothesis of evolutionary optimization based on the nonmonotonicity
of a chosen measure of noise must justify why it assumes that biological
evolution quantifies noise in that particular way. Finally, we show that not
only for exponentially distributed burst sizes but also for a wider class of
burst size distributions (e.g. Dirac delta and gamma) the control of gene
expression level by burst frequency modulation gives rise to proportional
scaling of variance of the protein number distribution to its mean, whereas the
control by amplitude modulation implies proportionality of protein number
variance to the mean squared.


title:
Ferroelectricity-induced asymmetrical two-dimensional electron gas in
  superlattices consisteing of insulating GdTiO3 and ferroelectric BaTiO3

abstract:
  Two-dimensional electron gas due to semiconductor interfaces can have high
mobility and exhibits superconductivity, magnetism, and other exotic properties
that are unexpected in constituent bulk materials. We study crystal structures,
electronic states, and magnetism of short-period (BTO)$_m$/(GTO)$_2$ ($m$=2 and
4) superlattices consisting of ferroelectric BaTiO$_3$ (BTO) and ferrimagnetic
insulating polar GdTiO$_3$ (GTO) by first principles calculations. Our
investigation shows that the middle Ti-O monolayer in the GTO layer becomes
metallic because the ferroelectricity in the insulating BTO layer induces an
inhomogeneous electric field against the polarity-produced electric field in
the GTO layer and thus differentially changes the d energy levels of the three
Ti-O monolayers related with the GTO layer. Through avoiding electron
reconstruction, the ferroelectric polarization also makes the electronic states
and magnetism of two interfacial Ti-O monolayers become substantially different
from those in the GTO/SrTiO$_3$ superlattices without ferroelectricity. Such
superlattices are interesting for potential spintronics applications because of
their unique asymmetrical two-dimensional electron-gas properties and possible
useful spin-orbit effects.


title: On panel-regular ~A_2 lattices

abstract:
  We study lattices on ~A_2 buildings that preserve types, act regularly on
each type of edge, and whose vertex stabilizers are cyclic. We show that
several of their properties, such as their automorphism group and isomorphism
class, can be determined from purely combinatorial data. As a consequence we
can show that the number of such lattices (up to isomorphism) grows
super-exponentially with the thickness parameter q.
  We look in more detail at the 3295 lattices with q in {2,3,4,5}. We show that
with one exception for each q these are all exotic. For the exotic examples we
prove that the automorphism group of the lattice and of the building coincide,
and that two lattices are quasi-isometric only if they are isomorphic.


title: On $q$-de Rham cohomology via $\Lambda$-rings

abstract:
  We show that Aomoto's $q$-deformation of de Rham cohomology arises as a
natural cohomology theory for $\Lambda$-rings. Moreover, Scholze's $(q-1)$-adic
completion of $q$-de Rham cohomology depends only on the Adams operations at
each residue characteristic. This gives a fully functorial cohomology theory,
including a lift of the Cartier isomorphism, for smooth formal schemes in mixed
characteristic equipped with a suitable lift of Frobenius. If we attach
$p$-power roots of $q$, the resulting theory is independent even of these lifts
of Frobenius, refining a comparison by Bhatt, Morrow and Scholze.


title:
Magnetoresistence engineering and singlet/triplet switching in InAs
  nanowire quantum dots with ferromagnetic sidegates

abstract:
  We present magnetoresistance (MR) experiments on an InAs nanowire quantum dot
device with two ferromagnetic sidegates (FSGs) in a split-gate geometry. The
wire segment can be electrically tuned to a single dot or to a double dot
regime using the FSGs and a backgate. In both regimes we find a strong MR and a
sharp MR switching of up to 25\% at the field at which the magnetizations of
the FSGs are inverted by the external field. The sign and amplitude of the MR
and the MR switching can both be tuned electrically by the FSGs. In a double
dot regime close to pinch-off we find {\it two} sharp transitions in the
conductance, reminiscent of tunneling MR (TMR) between two ferromagnetic
contacts, with one transition near zero and one at the FSG switching fields.
These surprisingly rich characteristics we explain in several simple resonant
tunneling models. For example, the TMR-like MR can be understood as a
stray-field controlled transition between singlet and a triplet double dot
states. Such local magnetic fields are the key elements in various proposals to
engineer novel states of matter and may be used for testing electron spin-based
Bell inequalities.


title:
The existence of continuous weak selections and orderability-type
  properties in products and filter spaces

abstract:
  Orderability, weak orderability and the existence of continuous weak
selections on filter spaces (i.e., spaces with a single non-isolated point) and
their products are discussed. We prove that a closed continuous image X of a
suborderable space must be hereditarily paracompact provided that its product
X\times Y with some non-discrete space Y has a separately continuous weak
selection.


title:
Semi-leptonic Production of $D_{sJ}(3040)$ and $D_J(3000)$ in $B_s$ and
  $B$ Decays

abstract:
  In this paper, we study the productions of the newly detected states
$D_{sJ}(3040)$ and $D_J(3000)$ observed by BABAR Collaboration and LHCb
Collaboration. We assume these states to be the $D_s(2P)$ and $D(2P)$ states
with the quantum number $J^P=1^+$ in our work. The results of improved
Bethe-Salpeter method indicate that the semi-leptonic decays via $B_s$ and $B$
into $D_{sJ}(3040)$ and $D_J(3000)$ have considerable branching ratios, for
example, Br($\bar{B}_s^0 \rightarrow
D{_{sJ}^+}(3040)e^-\bar{\nu}{_e}$)=$5.79\times10^{-4}$,
Br($\bar{B}^0\rightarrow D_{J}^+(3000)e^-\bar{\nu}{_e}$)=$2.63\times10^{-4}$,
which shows that these semi-leptonic decays can be accessible in experiments.


title:
The feasibility of launching physical layer attacks in visible light
  communication networks

abstract:
  One of the areas in which wireless networks based on visible light
communication (VLC) are considered superior to traditional radio-based
communication is security. The common slogan summarizing VLC security features
is: WYSIWYS - "What You See Is What You Send". However, especially in the case
of infrastructure downlink communication, security with respect to data
snooping, jamming and modification must be carefully provided for. This paper
examines the physical layer aspects of VLC networks with respect to possible
disruptions caused by rogue transmitters. We present the theoretical system
model that we use in simulations to evaluate various rogue transmission
scenarios in a typical office environment. We use estimated Bit Error Rate
(BER) as a measure of the effectiveness of jamming and rogue data transmission.
We find that it is quite easy to disrupt, and in some cases to even hijack
legitimate transmission.


title: On functions K and E generated by a sequence of moments

abstract:
  We study the asymptotic behaviour of the entire function \[ E(z) = \sum_{n\ge
0} \frac{z^n}{\gamma (n+1)} \] and the analytic function \[ K(z) = \frac1{2\pi
{\rm i}}\, \int_{c-{\rm i}\infty}^{c+{\rm i}\infty} z^{-s}\gamma (s)\, {\rm
d}s\,, \] which naturally appear in various classical problems of analysis.


title:
High order moment model for polydisperse evaporating sprays towards
  interfacial geometry

abstract:
  In this paper we propose a new Eulerian modeling and related accurate and
robust numerical methods, describing polydisperse evaporating sprays, based on
high order moment methods in size. The main novelty of this model is its
capacity to describe some geometrical variables of the droplet-gas interface,
by analogy with the liquid-gas interface in interfacial flows. For this
purpose, we use fractional size-moments, where the size variable is taken as
the droplet surface. In order to evaluate the evaporation of the polydisperse
spray, we use a smooth reconstruction which maximizes the Shannon entropy.
However, the use of fractional moments introduces some theoretical and
numerical difficulties, which need to be tackled. First, relying on a study of
the moment space, we extend the Maximum Entropy (ME) reconstruction of the size
distribution to the case of fractional moments. Then, we propose a new accurate
and realizable algorithm to solve the moment evolution due to evaporation,
which preserves the structure of the moment space. This algorithm is based on a
mathematical analysis of the kinetic evolution due to evaporation, where it
shown that the evolution of some negative order fractional moments have to be
properly predicted, a peculiarity related to the use of fractional moments. The
present model and numerical schemes yield an accurate and stable evaluationof
the moment dynamics with minimal number of variables, as well as a minimal
computational cost as with the EMSM model, but with the very interesting
additional capacity of coupling with diffuse interface model and transport
equation of averaged geometrical interface variables, which are essential in
oder to describe atomization.


title:
Time inhomogeneous Stochastic Differential Equations involving the local
  time of the unknown process, and associated parabolic operators

abstract:
  In this paper we study time-inhomogeneous versions of one-dimensional
Stochastic Differential Equations (SDE) involving the Local Time of the unknown
process on curves. After proving existence and uniqueness for these SDE under
mild assumptions, we explore their link with Parabolic Differential Equations
(PDE) with transmission conditions. We study the regularity of solutions of
such PDE and ensure the validity of a Feynman-Kac representation formula. These
results are then used to characterize the solutions of these SDE as
time-inhomogeneous Markov Feller processes.


title: Caract\`eres automorphes d'un groupe r\'eductif

abstract:
  Let $G$ be a reductive group defined over a number field. Denote $Z(\hat G)$
the center of the dual group. Langlands has defined some homomorphism from some
cohomology group of $Z(\hat G)$ into the group of automorphic characters of
$G$. We prove that it is bijective.


title: Complex refractive index variation in proton-damaged diamond

abstract:
  An accurate control of the optical properties of single crystal diamond
during microfabrication processes such as ion implantation plays a crucial role
in the engineering of integrated photonic devices. In this work we present a
systematic study of the variation of both real and imaginary parts of the
refractive index of single crystal diamond, when damaged with 2 and 3 MeV
protons at low-medium fluences (range: 10^15 - 10^17 cm^-2). After implanting
in 125x125 um^2 areas with a scanning ion microbeam, the variation of optical
pathlength of the implanted regions was measured with laser interferometric
microscopy, while their optical transmission was studied using a spectrometric
set-up with micrometric spatial resolution. On the basis of a model taking into
account the strongly non-uniform damage profile in the bulk sample, the
variation of the complex refractive index as a function of damage density was
evaluated.


title:
Appropriate probe condition for absorption imaging of ultracold $^6$Li
  atoms

abstract:
  One of the readily accessible observables in trapped cold-atom experiments is
the column density, which is determined from optical depth (OD) obtained from
absorption imaging and the absorption cross-section ($\sigma_{\rm abs}$). Here
we report on simple and accurate determination of OD for dense gases of light
atoms such as lithium-6. We investigate theoretically and experimentally an
appropriate condition for the probe intensity and duration to achieve good
signal-to-noise ratio by considering the influences of photon recoils and
photon shot noises. As a result, we have succeeded in measuring OD which
reached 2.5 with a signal-to-noise ratio of 10 under spatial resolution of 1.7
$\mu$m.


title:
Geometry of the vacant set left by random walk on random graphs,
  Wright's constants, and critical random graphs with prescribed degrees

abstract:
  We provide an explicit algorithm for sampling a uniform simple connected
random graph with a given degree sequence. By products of this central result
include:
  (i) continuum scaling limits of uniform simple connected graphs with given
degree sequence and asymptotics for the number of simple connected graphs with
given degree sequence under some regularity conditions, and
  (ii) scaling limits for the metric space structure of the maximal components
in the critical regime of both the configuration model and the uniform simple
random graph model with prescribed degree sequence under finite third moment
assumption on the degree sequence.
  As a substantive application we answer a question raised by Cerny and
Teixeira by obtaining the metric space scaling limit of maximal components in
the vacant set left by random walks on random regular graphs.


title:
Coupling quantum Monte Carlo and independent-particle calculations:
  self-consistent constraint for the sign problem based on density or density
  matrix

abstract:
  Quantum Monte Carlo (QMC) methods are one of the most important tools for
studying interacting quantum many-body systems. The vast majority of QMC
calculations in interacting fermion systems require a constraint to control the
sign problem. The constraint involves an input trial wave function which
restricts the random walks. We introduce a systematically improvable constraint
which relies on the fundamental role of the density or one-body density matrix.
An independent-particle calculation is coupled to an auxiliary-field QMC
calculation. The independent-particle solution is used as the constraint in
QMC, which then produces the input density or density matrix for the next
iteration. The constraint is optimized by the self-consistency between the
many-body and independent-particle calculations. The approach is demonstrated
in the two-dimensional Hubbard model by accurately determining the ground state
when collective modes separated by tiny energy scales are present in the
magnetic and charge correlations. Our approach also provides an ab initio way
to predict effective interaction parameters for independent-particle
calculations.


title:
A new kind of parallelism and its programming in the Explicitly
  Many-Processor Approach

abstract:
  The processor accelerators are effective because they are working not
(completely) on principles of stored program computers. They use some kind of
parallelism, and it is rather hard to program them effectively: a parallel
architecture by means of (and thinking in) sequential programming. The recently
introduced EMPA architecture uses a new kind of parallelism, which offers the
potential of reaching higher degree of parallelism, and also provides extra
possibilities and challenges. It not only provides synchronization and inherent
parallelization, but also takes over some duties typically offered by the OS,
and even opens the till now closed machine instructions for the end-user. A
toolchain for EMPA architecture with Y86 cores has been prepared, including an
assembler and a cycle-accurate simulator. The assembler is equipped with some
meta-instructions, which allow to use all advanced possibilities of the EMPA
architecture, and at the same time provide a (nearly) conventional-style
programming. The cycle accurate simulator is able to execute the EMPA-aware
object code, and is a good tool for developing algorithms for EMPA


title: An upper limit on the lateral vacancy diffusion length in diamond

abstract:
  Ion implantation is widely used to modify the structural, electrical and
optical properties of materials. By appropriate masking, this technique can be
used to define nano- and micro-structures. However, depending on the type of
mask used, experiments have shown that vacancy-related substrate modification
can be inferred tens of microns away from the edge of the mask used to define
the implanted region. This could be due to fast diffusion of vacancies from the
implanted area during annealing or to a geometric effect related to ion
scattering around the mask edges. For quantum and single-atom devices, stray
ion damage can be deleterious and must be minimized. In order to profile the
distribution of implantation-induced damage, we have used the nitrogen-vacancy
colour centre as a sensitive marker for vacancy concentration and distribution
following MeV He ion implantation into diamond and annealing. Results show that
helium atoms implanted through a mask clamped to the diamond surface are
scattered underneath the mask to distances in the range of tens of micrometers
from the mask edge. Implantation through a lithographically defined and
deposited mask, with no spacing between the mask and the substrate,
significantly reduces the scattering to <5 m but does not eliminate it. These
scattering distances are much larger than the theoretically estimated vacancy
diffusion distance of 260 nm under similar conditions. This paper shows that
diffusion, upon annealing, of vacancies created by ion implantation in diamond
is limited and the appearance of vacancies many tens of micrometers from the
edge of the mask is due to scattering effects.


title: The nature of the light variability of magnetic Of?p star HD 191612

abstract:
  A small fraction of hot OBA stars host global magnetic fields with field
strengths of the order of 0.1-10 kG. This leads to the creation of persistent
surface structures (spots) in stars with sufficiently weak winds as a result of
the radiative diffusion. These spots become evident in spectroscopic and
photometric variability. This type of variability is not expected in stars with
strong winds, where the wind inhibits the radiative diffusion. Therefore, a
weak photometric variability of the magnetic Of?p star HD 191612 is attributed
to the light absorption in the circumstellar clouds. We study the nature of the
photometric variability of HD 191612. We assume that the variability results
from variable wind blanketing induced by surface variations of the magnetic
field tilt and modulated by stellar rotation. We used our global kinetic
equilibrium (NLTE) wind models with radiative force determined from the
radiative transfer equation in the comoving frame (CMF) to predict the stellar
emergent flux. Our models describe the stellar atmosphere in a unified manner
and account for the influence of the wind on the atmosphere. The models are
calculated for different wind mass-loss rates to mimic the effect of magnetic
field tilt on the emergent fluxes. We integrate the emergent fluxes over the
visible stellar surface for individual rotational phases, and calculate the
rotationally modulated light curve of HD 191612. The wind blanketing that
varies across surface is able to explain a part of the observed light
variability in this star. The mechanism is able to operate even at relatively
low mass-loss rates. The remaining variability is most likely caused by the
flux absorption in circumstellar clouds. The variable wind blanketing is an
additional source of the light variability in massive stars. The presence of
the rotational light variability may serve as a proxy for the magnetic field.


title: The randomised Heston model

abstract:
  We propose a randomised version of the Heston model-a widely used stochastic
volatility model in mathematical finance-assuming that the starting point of
the variance process is a random variable. In such a system, we study the
small-and large-time behaviours of the implied volatility, and show that the
proposed randomisation generates a short-maturity smile much steeper (`with
explosion') than in the standard Heston model, thereby palliating the
deficiency of classical stochastic volatility models in short time. We
precisely quantify the speed of explosion of the smile for short maturities in
terms of the right tail of the initial distribution, and in particular show
that an explosion rate of~$t^\gamma$ ($\gamma\in[0,1/2]$) for the squared
implied volatility--as observed on market data--can be obtained by a suitable
choice of randomisation. The proofs are based on large deviations techniques
and the theory of regular variations.


title: Active Robust Learning

abstract:
  In many practical applications of learning algorithms, unlabeled data is
cheap and abundant whereas labeled data is expensive. Active learning
algorithms developed to achieve better performance with lower cost. Usually
Representativeness and Informativeness are used in active learning algoirthms.
Advanced recent active learning methods consider both of these criteria.
Despite its vast literature, very few active learning methods consider noisy
instances, i.e. label noisy and outlier instances. Also, these methods didn't
consider accuracy in computing representativeness and informativeness. Based on
the idea that inaccuracy in these measures and not taking noisy instances into
consideration are two sides of a coin and are inherently related, a new loss
function is proposed. This new loss function helps to decrease the effect of
noisy instances while at the same time, reduces bias. We defined "instance
complexity" as a new notion of complexity for instances of a learning problem.
It is proved that noisy instances in the data if any, are the ones with maximum
instance complexity. Based on this loss function which has two functions for
classifying ordinary and noisy instances, a new classifier, named
"Simple-Complex Classifier" is proposed. In this classifier there are a simple
and a complex function, with the complex function responsible for selecting
noisy instances. The resulting optimization problem for both learning and
active learning is highly non-convex and very challenging. In order to solve
it, a convex relaxation is proposed.


title:
Growth description of $p$th means of the Green potential in the unit
  ball

abstract:
  We describe the growth of $p$th means, $1<p<\frac{2n-1}{2(n-1)}$, of the
invariant Green potential in the unit ball in $\mathbb{C}^n$ in terms of
smoothness properties of a measure.
  In particular, a criterion of boundedness of $p$th means of the potential is
obtained, a result of M. Stoll is generalized.


title: A Simple Guide to S3 Methods

abstract:
  Writing functions in R is an important skill for anyone using R. S3 methods
allow for functions to be generalised across different classes and are easy to
implement. Whilst many R users are be adept at creating their own functions, it
seems that there is room for many more to take advantage of R's S3 methods.
This paper provides a simple and targeted guide to explain what S3 methods are,
why people should them, and how they can do it.


title: Monte-Carlo study of Dirac semimetals phase diagram

abstract:
  In this paper the phase diagram of Dirac semimetals is studied within lattice
Monte-Carlo simulation. In particular, we concentrate on the dynamical chiral
symmetry breaking which results in semimetal/insulator transition. Using
numerical simulation we determined the values of the critical coupling constant
of the semimetal/insulator transition for different values of the anisotropy of
the Fermi velocity. This measurement allowed us to draw tentative phase diagram
for Dirac semimetals. It turns out that within the Dirac model with Coulomb
interaction both Na$_3$Bi and Cd$_3$As$_2$ known experimentally to be Dirac
semimetals would lie deeply in the insulating region of the phase diagram. It
probably shows a decisive role of screening of the interelectron interaction in
real materials, similar to the situation in graphene.


title:
Total Recursion over Lexicographical Orderings: Elementary Recursive
  Operators Beyond PR

abstract:
  In this work we generalize primitive recursion in order to construct a
hierarchy of terminating total recursive operators which we refer to as {\em
leveled primitive recursion of order $i$}($\mathbf{PR}_{i}$). Primitive
recursion is equivalent to leveled primitive recursion of order $1$
($\mathbf{PR}_{1}$). The functions constructable from the basic functions make
up $\mathbf{PR}_{0}$. Interestingly, we show that $\mathbf{PR}_{2}$ is a
conservative extension of $\mathbf{PR}_{1}$. However, members of the hierarchy
beyond $\mathbf{PR}_{2}$, that is $\mathbf{PR}_{i}$ where $i\geq 3$, can
formalize the Ackermann function, and thus are more expressive than primitive
recursion. It remains an open question which members of the hierarchy are more
expressive than the previous members and which are conservative extensions. We
conjecture that for all $i\geq 1$ $\mathbf{PR}_{2i} \subset
\mathbf{PR}_{2i+1}$. Investigation of further extensions is left for future
work.


title: On Hypohamiltonian Snarks and a Theorem of Fiorini

abstract:
  We discuss an omission in the statement and proof of Fiorini's 1983 theorem
on hypohamiltonian snarks and present a version of this theorem which is more
general in several ways. Using Fiorini's erroneous result, Steffen showed that
hypohamiltonian snarks exist for some $n \ge 10$ and each even $n \ge 92$. We
rectify Steffen's proof by providing a correct demonstration of a technical
lemma on flower snarks, which might be of separate interest. We then strengthen
Steffen's theorem to the strongest possible form by determining all orders for
which hypohamiltonian snarks exists. This also strengthens a result of
M\'{a}\v{c}ajov\'{a} and \v{S}koviera. Finally, we verify a conjecture of
Steffen on hypohamiltonian snarks up to 36 vertices.


title: Lots of Aperiodic Sets of Tiles

abstract:
  Aperiodic tiling --- a form of complex global geometric structure arising
through locally checkable, constant-time matching rules --- has long been
closely tied to a wide range of physical, information-theoretic, and
foundational applications, but its study and use has been hindered by a lack of
easily generated examples. Through readily generalized, robust techniques for
controlling hierarchical structure, we increase the catalogue of explicit
constructions of aperiodic sets of tiles hundreds-fold, in lots, easily
assembled and configured from atomic subsets of 211 tiles, enforcing 25,380
distinct "domino" substitution tiling systems. Among these, we notice three
non-periodic, non-unique decomposition substitution tiling systems.


title: The Pegasus Tiles: an aperiodic pair of tiles

abstract:
  The Pegasus tiles are an aperiodic pair of tiles with "tip to tip" matching
rules, first drawn in 1996. We present them here.


title: The Trilobite and Crab: a full explanation

abstract:
  The trilobite and crab are among the very simplest aperiodic sets of tiles
known: two tiles in eight translation classes. Yet the proof that they are an
aperiodic set is surprisingly complex.


title: Matching Rules for the Sphinx Tiling Substitution

abstract:
  We give a set of tiles that enforces the sphinx tiling substitution system;
the tiles are thus aperiodic.


title:
The Moser-Trudinger inequality and its extremals on a disk via energy
  estimates

abstract:
  We study the Dirichlet energy of non-negative radially symmetric critical
points $u_\mu$ of the Moser-Trudinger inequality on the unit disc in
$\mathbb{R}^2$, and prove that it expands as
$$4\pi+\frac{4\pi}{\mu^{4}}+o(\mu^{-4})\le \int_{B_1}|\nabla u_\mu|^2dx\le
4\pi+\frac{6\pi}{\mu^{4}}+o(\mu^{-4}),\quad \text{as }\mu\to\infty,$$ where
$\mu=u_\mu(0)$ is the maximum of $u_\mu$. As a consequence, we obtain a new
proof of the Moser-Trudinger inequality, of the Carleson-Chang result about the
existence of extremals, and of the Struwe and Lamm-Robert-Struwe multiplicity
result in the supercritical regime (only in the case of the unit disk).
  Our results are stable under sufficiently weak perturbations of the
Moser-Trudinger functional. We explicitly identify the critical level of
perturbation for which, although the perturbed Moser-Trudinger inequality still
holds, the energy of its critical points converges to $4\pi$ from below. We
expect, in some of these cases, that the existence of extremals does not hold,
nor the existence of critical points in the supercritical regime.


title: A bound on the Carath\'eodory number

abstract:
  The Carath\'eodory number k(K) of a pointed closed convex cone K is the
minimum among all the k for which every element of K can be written as a
nonnegative linear combination of at most k elements belonging to extreme rays.
Carath\'eodory's Theorem gives the bound k(K) <= dim (K). In this work we
observe that this bound can be sharpened to k(K) <= l-1, where l is the length
of the longest chain of nonempty faces contained in K, thus tying the
Carath\'eodory number with a key quantity that appears in the analysis of
facial reduction algorithms. We show that this bound is tight for several
families of cones, which include symmetric cones and the so-called smooth
cones. We also give a family of examples showing that this bound can also fail
to be sharp. In addition, we furnish a new proof of a result by G\"uler and
Tun\c{c}el which states that the Carath\'eodory number of a symmetric cone is
equal to its rank. Finally, we connect our discussion to the notion of cp-rank
for completely positive matrices.


title:
Ultra-smooth single crystal diamond surfaces resulting from implantation
  and lift-off processes

abstract:
  A method for obtaining a smooth, single crystal diamond surface is presented,
whereby a sacrificial defective layer is created by implantation and
graphitized by annealing before being selectively etched. We have used O+ at
240 keV, the main process variables being the ion fluence (ranging from 3x10^15
cm^-2 to 3x10^17 cm^-2) and the final etching process (wet etch, H2 plasma and
annealing in air). The substrates were characterized by atomic force
microscopy, optical profilometry and white beam X-ray topography. The influence
of the various process parameters on the resulting lift-off efficiency and
final surface roughness is discussed. An O+ fluence of 2x10^17 cm^-2 was found
to result in sub-nanometre roughness over tens of um^2.


title:
Sunspot positions, areas, and group tilt angles for 1611-1631 from
  observations by Christoph Scheiner

abstract:
  Digital images of the observations printed in the books "Rosa Ursina sive
solis" and "Prodromus pro sole mobili" by Christoph Scheiner as well as the
drawings from Scheiner's letters to Marcus Welser are analysed in order to
obtain information on positions and sizes of sunspots that appeared before the
Maunder minimum. In most cases, the given orientation of the ecliptic is used
to set up the heliographic coordinate system for the drawings. Positions and
sizes are measured manually on the screen. Very early drawings have no
indication of their orientation. A rotational matching using common spots of
adjacent days is used in some cases, while in other cases, the assumption of
images being aligned with a zenith-horizon coordinate system appeared to be the
most probable. In total, 8167 sunspots were measured. A distribution of sunspot
latitudes versus time (butterfly diagram) is obtained for Scheiner's
observations. The observations of 1611 are very inaccurate, the drawings of
1612 have at least an indication of their orientation, while the remaining part
of the spot positions from 1618-1631 have good to very good accuracy. We also
computed 697 tilt angles of apparently bipolar sunspot groups observed in the
period 1618-1631. We find that the average tilt angle of nearly 4 degrees is
not significantly different from 20th-century values.


title: Multiscale Blind Source Separation

abstract:
  We provide a new methodology for statistical recovery of single linear
mixtures of piecewise constant signals (sources) with unknown mixing weights
and change points in a multiscale fashion. We show exact recovery within an
$\epsilon$-neighborhood of the mixture when the sources take only values in a
known finite alphabet. Based on this we provide the SLAM (Separates Linear
Alphabet Mixtures) estimators for the mixing weights and sources. For Gaussian
error, we obtain uniform confidence sets and optimal rates (up to log-factors)
for all quantities. SLAM is efficiently computed as a nonconvex optimization
problem by a dynamic program tailored to the finite alphabet assumption. Its
performance is investigated in a simulation study. Finally, it is applied to
assign copy-number aberrations from genetic sequencing data to different clones
and to estimate their proportions.


title: Composition arithmetic for locally one-to-one entire mappings

abstract:
  This paper describes a part of the factorization theory of the family of all
the entire functions with non vanishing derivatives. In particular it proves
that this family of mappings contains primes. This assures that this family of
entire functions has two non degenerate fractal representations.


title: On Particles and Primes

abstract:
  Primes in the two complete associative normed division algebras C and H have
affinities with structures seen in the standard model of particle physics. On
the integers in the two algebras, there are two equivalence relations: a strong
one, related to a U(1) and SU(3) symmetry allowing to permute and switch signs
of the coordinates of the integers, as well as a weak relation with origins
from units U(1),SU(2) in the algebra. Weak equivalence classes within the
strong equivalence classes of odd primes in C case relate to leptons, the inert
ones being neutrino like, and the split ones resembling electron-positron
pairs. In the H case, for odd primes, the equivalence classes come in groups of
two or three, leading to a caricature of hadrons featuring either mesons built
by a quark pair or then baryons obtained by quark triplets. We can now list for
every rational prime p all these particles and attach fractional charges to its
constituents.


title: Modification of the structure of diamond with MeV ion implantation

abstract:
  We present experimental results and numerical simulations to investigate the
modification of structural-mechanical properties of ion-implanted
single-crystal diamond. A phenomenological model is used to derive an
analytical expression for the variation of mass density and elastic properties
as a function of damage density in the crystal. These relations are applied
together with SRIM Monte Carlo simulations to set up Finite Element simulations
for the determination of internal strains and surface deformation of
MeV-ion-implanted diamond samples. The results are validated through comparison
with high resolution X-ray diffraction and white-light interferometric
profilometry experiments. The former are carried out on 180 keV B implanted
diamond samples, to determine the induced structural variation, in terms of
lattice spacing and disorder, whilst the latter are performed on 1.8 MeV He
implanted diamond samples to measure surface swelling. The effect of thermal
processing on the evolution of the structural-mechanical properties of damaged
diamond is also evaluated by performing the same profilometric measurements
after annealing at 1000 {\deg}C, and modeling the obtained trends with a
suitably modified analytical model. The results allow the development of a
coherent model describing the effects of MeV-ion-induced damage on the
structural-mechanical properties of single-crystal diamond. In particular, we
suggest a more reliable method to determine the so-called diamond
"graphitization threshold" for the considered implantation type.


title: Ambiguity in deriving Larmor's formula from the LAD equation of motion

abstract:
  The power radiated by a moving charge is given by Larmor's formula which can
be derived by integrating the Li\'enard-Wiechert potential over the whole past
history of the charge. However, extracting the same result from the
Lorent-Abraham-Dirac (LAD) equation of motion is problematic. This is well
known for uniform proper acceleration for which case the radiation force
vanishes and hence the very origin of the radiated energy is not clear, leading
to an energy balance paradox. The purpose of this letter is first to evince
that this problem occurs in the general case and not only for uniform
acceleration. Second we show that the widely accepted treatment based on the
bound field technique cannot fix the energy balance discrepancy. Indeed the
related Schott term is not a legitimate four-momentum for being indefinite and
not conserved.


title:
Constraints on hadronic models in extensive air showers with the Pierre
  Auger Observatory

abstract:
  Extensive air showers initiated by ultra-high energy cosmic rays are
sensitive to the details of hadronic interactions models, so we present the
main results obtained using the data of the Pierre Auger Observatory. The depth
at which the maximum of the electromagnetic development takes place is the most
sensitive parameter to infer the nature of the cosmic rays. However, the
hadronic models cannot describe consistently the maximum and the muon
measurements at energies higher than those reached at the LHC.


title: Minimizing Quadratic Functions in Constant Time

abstract:
  A sampling-based optimization method for quadratic functions is proposed. Our
method approximately solves the following $n$-dimensional quadratic
minimization problem in constant time, which is independent of $n$:
$z^*=\min_{\mathbf{v} \in \mathbb{R}^n}\langle\mathbf{v}, A \mathbf{v}\rangle +
n\langle\mathbf{v}, \mathrm{diag}(\mathbf{d})\mathbf{v}\rangle +
n\langle\mathbf{b}, \mathbf{v}\rangle$, where $A \in \mathbb{R}^{n \times n}$
is a matrix and $\mathbf{d},\mathbf{b} \in \mathbb{R}^n$ are vectors. Our
theoretical analysis specifies the number of samples $k(\delta, \epsilon)$ such
that the approximated solution $z$ satisfies $|z - z^*| = O(\epsilon n^2)$ with
probability $1-\delta$. The empirical performance (accuracy and runtime) is
positively confirmed by numerical experiments.


title:
Bayesian Inference for Sequential Treatments under Latent Sequential
  Ignorability

abstract:
  We focus on causal inference for longitudinal treatments, where units are
assigned to treatments at multiple time points, aiming to assess the effect of
different treatment sequences on an outcome observed at a final point. A common
assumption in similar studies is Sequential Ignorability (SI): treatment
assignment at each time point is assumed independent of future potential
outcomes given past observed outcomes and covariates. SI is questionable when
treatment participation depends on individual choices, and treatment assignment
may depend on unobservable quantities associated with future outcomes. We rely
on Principal Stratification to formulate a relaxed version of SI: Latent
Sequential Ignorability (LSI) assumes that treatment assignment is
conditionally independent on future potential outcomes given past treatments,
covariates and principal stratum membership, a latent variable defined by the
joint value of observed and missing intermediate outcomes. We evaluate SI and
LSI, using theoretical arguments and simulation studies to investigate the
performance of the two assumptions when one holds and inference is conducted
under both. Simulations show that when SI does not hold, inference performed
under SI leads to misleading conclusions. Conversely, LSI generally leads to
correct posterior distributions, irrespective of which assumption holds.


title:
Time resolved spectroscopy and photometry of three little known bright
  cataclysmic variables: LS IV -08$^{\rm o}$ 3, HQ Monocerotis and ST
  Chamaeleontis

abstract:
  As part of a project to better characterize comparatively bright but so far
little studied cataclysmic variables in the southern hemisphere, we have
obtained spectroscopic and photometric data of the nova-like variables LS IV
-08$^{\rm o}$ 3 and HQ Mon, and of the Z Cam type dwarf nova ST Cha. The
spectra of all systems are as expected for their respective types. We derive
improved orbital ephemeris of LS IV -08$^{\rm o}$ 3 and map its accretion disk
in the light of the H$\alpha$ emission using Doppler tomography. We find that
the emission has a two component origin, arising in the outer parts of the
accretion disk and possibly on the illuminated face of the secondary star. The
light curve of LS IV -08$^{\rm o}$ 3 exhibits a low level of flickering and
indications for a modulation on the orbital period. Spectroscopy of HQ Mon
suggests an orbital period of $\approx$5.15 hours which is incompatible with
previous (uncertain) estimates. The light curves show the typical low scale
flickering of UX UMa type nova-like systems, superposed upon variations on
longer time scales. During one night a modulation with a period of $\approx$41
min is observed, visible for at least 4 hours. However, it does not repeat
itself in other nights. A spectroscopic orbital period of $\approx$5.5 hours is
derived for ST Cha. A previously suspected period of 6.8 hours (or
alternatively 9.6 hours), based on historical photographic photometry is
incompatible with the spectroscopic period. Moreover, we show that our new as
well as previous photometry does not contain evidence for the quoted
photometric period.


title:
New Technology Assessment in Entrepreneurial Financing - Can
  Crowdfunding Predict Venture Capital Investments?

abstract:
  Recent years have seen an upsurge of novel sources of new venture financing
through crowdfunding (CF). We draw on 54,943 successfully crowdfunded projects
and 3,313 venture capital (VC) investments throughout the period
04/2012-06/2015 to investigate, on the aggregate level, how crowdfunding is
related to a more traditional source of entrepreneurial finance, venture
capital. Granger causality tests support the view that VC investments follow
crowdfunding investments. Cointegration tests also suggest a long-run
relationship between crowdfunding and VC investments, while impulse response
functions (IRF) indicate a positive effect running from CF to VC within two to
six months. Crowdfunding seems to help VC investors in assessing future trends
rather than crowding them out of the market.


title: Quantum Mutual Information as a Probe for Many-Body Localization

abstract:
  We demonstrate that the quantum mutual information (QMI) is a useful probe to
study many-body localization (MBL). First, we focus on the detection of a
metal--insulator transition for two different models, the noninteracting
Aubry-Andr\'e-Harper model and the spinless fermionic disordered Hubbard chain.
We find that the QMI in the localized phase decays exponentially with the
distance between the regions traced out, allowing us to define a correlation
length, which converges to the localization length in the case of one particle.
Second, we show how the QMI can be used as a dynamical indicator to distinguish
an Anderson insulator phase from an MBL phase. By studying the spread of the
QMI after a global quench from a random product state, we show that the QMI
does not spread in the Anderson insulator phase but grows logarithmically in
time in the MBL phase.


title:
Search for gamma-ray line features from Milky Way satellites with
  Fermi-LAT Pass 8 data

abstract:
  With 91 months of the publicly available Fermi-LAT Pass 8 data, we analyze
the gamma-ray emission from the Milky Way satellites to search for potential
line signals due to the annihilation of dark matter particles into double
photons. The searched targets include a sample of dwarf spheroidal galaxies,
the Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC). No
significant line emission has been found neither in the stacked dwarf galaxy
sample nor in the direction of LMC/SMC. The corresponding upper limits on the
cross section of DM annihilation into two photons are derived. Compared with
results of previous gamma-ray line searches with the Pass 7 data, the current
constraints on the line emission from dwarf spheroidal galaxies has been
significantly improved in a wide energy range. With the rapid increase of the
sample of dwarf spheroidal galaxies (candidates), we expect that the
sensitivity of gamma ray line searches will be significantly improved in the
near future.


title: Comment on "Non-representative Quantum Mechanical Weak Values"

abstract:
  Svensson [Found. Phys. 45, 1645 (2015)] argued that the concept of the weak
value of an observable of a pre- and post-selected quantum system cannot be
applied when the expectation value of the observable in the initial state
vanishes. Svensson's argument is analyzed and shown to be inconsistent using
several examples.


title: Higher order asymptotics of Generalized Fiducial Distribution

abstract:
  Generalized Fiducial Inference (GFI) is motivated by R.A. Fisher's approach
of obtaining posterior-like distributions when there is no prior information
available for the unknown parameter. Without the use of Bayes' theorem GFI
proposes a distribution on the parameter space using a technique called
increasing precision asymptotics \cite{hannig2013generalized}. In this article
we analyzed the regularity conditions under which the Generalized Fiducial
Distribution (GFD) will be first and second order exact in a frequentist sense.
We used a modification of an ingenious technique named "Shrinkage method"
\cite{bickel1990decomposition}, which has been extensively used in the
probability matching prior contexts, to find the higher order expansion of the
frequentist coverage of Fiducial quantile. We identified when the higher order
terms of one-sided coverage of Fiducial quantile will vanish and derived a
workable recipe for obtaining such GFDs. These ideas are demonstrated on
several examples.


title:
Semantics derived automatically from language corpora contain human-like
  biases

abstract:
  Artificial intelligence and machine learning are in a period of astounding
growth. However, there are concerns that these technologies may be used, either
with or without intention, to perpetuate the prejudice and unfairness that
unfortunately characterizes many human institutions. Here we show for the first
time that human-like semantic biases result from the application of standard
machine learning to ordinary language---the same sort of language humans are
exposed to every day. We replicate a spectrum of standard human biases as
exposed by the Implicit Association Test and other well-known psychological
studies. We replicate these using a widely used, purely statistical
machine-learning model---namely, the GloVe word embedding---trained on a corpus
of text from the Web. Our results indicate that language itself contains
recoverable and accurate imprints of our historic biases, whether these are
morally neutral as towards insects or flowers, problematic as towards race or
gender, or even simply veridical, reflecting the {\em status quo} for the
distribution of gender with respect to careers or first names. These
regularities are captured by machine learning along with the rest of semantics.
In addition to our empirical findings concerning language, we also contribute
new methods for evaluating bias in text, the Word Embedding Association Test
(WEAT) and the Word Embedding Factual Association Test (WEFAT). Our results
have implications not only for AI and machine learning, but also for the fields
of psychology, sociology, and human ethics, since they raise the possibility
that mere exposure to everyday language can account for the biases we replicate
here.


title: Root Sparse Bayesian Learning for Off-Grid DOA Estimation

abstract:
  The performance of the existing sparse Bayesian learning (SBL) methods for
off-gird DOA estimation is dependent on the trade off between the accuracy and
the computational workload. To speed up the off-grid SBL method while remain a
reasonable accuracy, this letter describes a computationally efficient root SBL
method for off-grid DOA estimation, where a coarse refinable grid, whose
sampled locations are viewed as the adjustable parameters, is adopted. We
utilize an expectation-maximization (EM) algorithm to iteratively refine this
coarse grid, and illustrate that each updated grid point can be simply achieved
by the root of a certain polynomial. Simulation results demonstrate that the
computational complexity is significantly reduced and the modeling error can be
almost eliminated.


title:
Infinite Barriers and Symmetries for a Few Trapped Particles in One
  Dimension

abstract:
  This article investigates the properties of a few interacting particles
trapped in a few wells and how these properties change under adiabatic tuning
of interaction strength and inter-well tunneling. While some system properties
are dependent on the specific shapes of the traps and the interactions, this
article applies symmetry analysis to identify generic features in the spectrum
of stationary states of few-particle, few-well systems. Extended attention is
given to a simple but flexible three-parameter model of two particles in two
wells in one dimension. A key insight is that two limiting cases, hard-core
repulsion and no inter-well tunneling, can both be treated as emergent
symmetries of the few-particle Hamiltonian. These symmetries are the
mathematical consequences of infinite barriers in configuration space. They are
necessary to explain the pattern of degeneracies in the energy spectrum, to
understand how degeneracies are broken for models away from limiting cases, and
to explain separability and integrability. These symmetry methods are
extendable to more complicated models and the results have practical
consequences for stable state control in few-particle, few-well systems with
ultracold atoms in optical traps.

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


title: Luminescence centers in proton irradiated single crystal CVD diamond

abstract:
  Diamond displays a large variety of luminescence centers which define its
optical properties and can be either created or modified by irradiation. The
main purpose of the present work is to study the radiation hardness of several
of such centers in homoepitaxial single crystal CVD diamond by following the
evolution of photoluminescence and ionoluminescence upon 2 MeV proton
irradiation. Luminescence decays were observed with values of the fluence at
half of the starting luminescence (F1/2) of the order of 1014 cm-2. The 3H
center displayed a non monotonic behavior, with a growing behavior and a
subsequent decay with a rather high F1/2 value (in the order of few 1016 cm-2),
maintaining at the highest fluences an intensity significantly higher than the
blue A-band. A simple model based on a double-exponential trend was defined to
fit with satisfactory accuracy the evolution of the 3H center. Several PL
centers (namely: 3H, TR12, 491 nm, 494 nm) exhibited clear correlations and
anti-correlations in their fluence dependences, which were considered in the
attempt to acquire some insight into their possible alternative attributions.


title: A new $G$-parity violating amplitude in the $J/\psi$ decay?

abstract:
  The $J/\psi$ meson has negative $G$-parity so that, in the limit of isospin
conservation, its decay into $\pi^+\pi^-$ should be purely electromagnetic.
However, the measured branching fraction $\mathcal{B}(J/\psi\to\pi^+\pi^-)$
exceeds by more than 3.9 standard deviations the expectation computed according
to BaBar data on the $e^+e^-\to\pi^+\pi^-$ cross section. The possibility that
the two-gluon plus one-photon decay mechanism is not suppressed by $G$-parity
conservation is discussed, even by considering other multi-pion decay channels.
As also obtained by phenomenological computation, such a decay mechanism could
be responsible for the observed discrepancy. Finally, we notice that the BESIII
experiment, having the potential to perform an accurate measurement of the
$e^+e^-\to\pi^+\pi^-$ cross section in the 3 GeV energy region, can definitely
prove or disprove this strong $G$-parity-violating mechanism by confirming or
confuting the BaBar data.


title:
Design of two combined health recommender systems for tailoring messages
  in a smoking cessation app

abstract:
  In this article, we describe the design of two recommender systems (RS)
designed to support the smoking cessation process through a mobile application.
We plan to use a hybrid RS (content-based, utility-based, and demographic
filtering) to tailor health recommendation messages, and a content-based RS to
schedule a timely delivery of the message. We also define metrics that we will
use to assess their performance, helping people quit smoking when we run the
pilot.


title:
Quantile Dependence between Stock Markets and its Application in
  Volatility Forecasting

abstract:
  This paper examines quantile dependence between international stock markets
and evaluates its use for improving volatility forecasting. First, we analyze
quantile dependence and directional predictability between the US stock market
and stock markets in the UK, Germany, France and Japan. We use the
cross-quantilogram, which is a correlation statistic of quantile hit processes.
The detailed dependence between stock markets depends on specific quantile
ranges and this dependence is generally asymmetric; the negative spillover
effect is stronger than the positive spillover effect and there exists strong
directional predictability from the US market to the UK, Germany, France and
Japan markets. Second, we consider a simple quantile-augmented volatility model
that accommodates the quantile dependence and directional predictability
between the US market and these other markets. The quantile-augmented
volatility model provides superior in-sample and out-of-sample volatility
forecasts.


title:
On Anderson Localization and Chiral Anomaly in Disordered Time-Reversal
  Invariant Weyl Semimetals: Nonperturbative and Berry Phase Effects

abstract:
  Weyl semimetal, a three-dimensional electronic system with relativistic
linear energy dispersion around gapless points carrying nontrivial Berry
charge, is predicted to exhibit a wealth of unique response and transport
properties.A crucial question is whether those properties are robust against
disorder and whether Anderson localization occurs.In this work, the effects of
nonperturbative topological (vortex loop) excitations and Berry phase in
disordered time-reversal invariant 3d Weyl semimetal are studied.It is shown
that the chiral symmetry is restored in the nonlinear sigma model describing
the diffusons upon disorder average as any net topological term and its
delocalization result do not take effect at sufficiently short length
scales.Anderson localization occurs at sufficiently strong disorder and we
predict that chirality and related phenomena disappear at such
transition.Nevertheless, we uncover a mechanism that originates from Berry
phase that impedes such localization effect.We show the occurrence of
destructive interference between the vortex loops and between scattering paths
due to the the vortex loops' Berry phase which resists the Anderson
localization.We emphasize the applicability of our theory to the candidate Weyl
materials where we point out the consistency of our theory with a recent
experimental finding of the absent chiral anomaly in a noncentrosymmetric Weyl
semimetal.


title: Is Electroweak Symmetry Breaking Still Natural in the MSSM?

abstract:
  The absence of any signal of supersymmetry (SUSY) at the LHC has raised the
SUSY particle mass scale compared to $Z$ boson mass $M_Z$. We investigate the
naturalness of the electroweak symmetry breaking after considering radiative
symmetry breaking along with 125 GeV Higgs mass. We find that the important
quantity to measure the naturalness of the hierarchy between the SUSY scale and
$M_Z$ is the separation between the radiative symmetry breaking scale, i.e.,
where $m_{H_u}^2+\mu^2$ turns negative for large $\tan\beta$ case ($\mu$ is the
Higgsino mass and $m_{H_u}$ is the SUSY breaking up-type Higgs boson mass) and
the average stop mass. Using this measure, one can show that the electroweak
symmetry breaking can be natural even if $\mu$ is large contrary to the
prevailing claim that $\mu$ is needed to be small to maintain the naturalness.


title: Charting the future frontier(s) of particle production

abstract:
  This short note describes the long collaborative effort between Arizona and
Krak\'ow, showing some of the key strangeness signatures of quark-gluon plasma.
It further presents an annotated catalog of foundational questions defining the
research frontiers which I believe can be addressed in the foreseeable future
in the context of relativistic heavy ion collision experiments. The list
includes topics that are specific to the field, and ventures towards the
known-to-be-unknown that may have a better chance with ions as compared to
elementary interactions.


title: Real identifiability vs complex identifiability

abstract:
  Let $T$ be a real tensor of (real) rank $r$. $T$ is 'identifiable' when it
has a unique decomposition in terms of rank $1$ tensors. There are cases in
which the identifiability fails over the complex field, for general tensors of
rank $r$. This behavior is quite peculiar when the rank $r$ is submaximal.
Often, the failure is due to the existence of an elliptic normal curve through
general points of the corresponding Segre, Veronese or Grassmann variety. We
prove the existence of nonempty euclidean open subsets of some variety of
tensors of rank $r$, whose elements have several decompositions over $\mathbb
C$, but only one of them is formed by real summands. Thus, in the open sets,
tensors are not identifiable over $\mathbb C$, but are identifiable over
$\mathbb R$.
  We also provide examples of non trivial euclidean open subsets in a whole
space of symmetric tensors (of degree $7$ and $8$ in three variables) and of
almost unbalanced tensors Segre Product ($\mathbb P^2\times \mathbb P^4\times
\mathbb P^9$) whose elements have typical real rank equal to the complex rank,
and are identifiable over $\mathbb R$, but not over $\mathbb C$. On the
contrary, we provide examples of tensors of given real rank, for which real
identifiability cannot hold in non-trivial open subsets.


title: Spitzer Space Telescope Mid-IR Light Curves of Neptune

abstract:
  We have used the Spitzer Space Telescope in February 2016 to obtain high
cadence, high signal-to-noise, 17-hour duration light curves of Neptune at 3.6
and 4.5 $\mu$m. The light curve duration was chosen to correspond to the
rotation period of Neptune. Both light curves are slowly varying with time,
with full amplitudes of 1.1 mag at 3.6 $\mu$m and 0.6 mag at 4.5 $\mu$m. We
have also extracted sparsely sampled 18-hour light curves of Neptune at W1 (3.4
$\mu$m) and W2 (4.6 $\mu$m) from the WISE/NEOWISE archive at six epochs in
2010-2015. These light curves all show similar shapes and amplitudes compared
to the Spitzer light curves but with considerable variation from epoch to
epoch. These amplitudes are much larger than those observed with Kepler/K2 in
the visible (amplitude $\sim$0.02 mag) or at 845 nm with the Hubble Space
Telescope in 2015 and at 763 nm in 2016 (amplitude $\sim$ 0.2 mag). We
interpret the Spitzer and WISE light curves as arising entirely from reflected
solar photons, from higher levels in Neptune's atmosphere than for K2. Methane
gas is the dominant opacity source in Neptune's atmosphere, and methane
absorption bands are present in the HST 763, and 845 nm, WISE W1, and Spitzer
3.6 $\mu$m filters.


title: A Two-weight inequality between $L^p(\ell^2)$ and $L^p$

abstract:
  We consider boundedness of a certain positive dyadic operator $$ T^\sigma
\colon L^p(\sigma; \ \! \ell^2) \to L^p(\omega), $$ that arose during our
attempts to develop a two-weight theory for the Hilbert transform in $L^p$.
Boundedness of $T^\sigma$ is characterized when $p \in [2, \infty)$ in terms of
certain testing conditions. This requires a new Carleson-type embedding theorem
that is also proved.


title: Bulk-synchronous pseudo-streaming algorithms for many-core accelerators

abstract:
  The bulk-synchronous parallel (BSP) model provides a framework for writing
parallel programs with predictable performance. In this paper we extend the BSP
model to support what we will call pseudo-streaming algorithms for
accelerators. We also generalize the BSP cost function to these algorithms, so
that it is possible to predict the running time for programs targeting
many-core accelerators and to identify possible bottlenecks. Several examples
of algorithms within this new framework will be explored. We extend the BSPlib
standard by proposing a small number of new BSP primitives to create and use
streams in a portable way. We will introduce a software library called Epiphany
BSP that implements these ideas for the Parallella development board. Finally
we will give experimental results for pseudo-streaming algorithms on the
Parallella platform.


title:
Jet-like correlations with neutral pion triggers in pp and central Pb-Pb
  collisions at 2.76 TeV

abstract:
  We present measurements of two-particle correlations with neutral pion
trigger particles of transverse momenta $8 < p_{\mathrm{T}}^{\rm trig} <
16~\mathrm{GeV}/c$ and associated charged particles of $0.5 <
p_{\mathrm{T}}^{\rm assoc} < 10~\mathrm{GeV}/c$ versus the azimuthal angle
difference $\Delta\varphi$ at midrapidity in pp and central Pb-Pb collisions at
$\sqrt{s_{\mathrm{NN}}}=2.76$ TeV with ALICE. The new measurements exploit
associated charged hadrons down to $0.5~\mathrm{GeV}/c$, which significantly
extends our previous measurement that only used charged hadrons above
$3~\mathrm{GeV}/c$. After subtracting the contributions of the flow background,
$v_2$ to $v_5$, the per-trigger yields are extracted for $|\Delta\varphi|<0.7$
on the near and for $|\Delta\varphi-\pi| < 1.1$ on the away side. The ratio of
per-trigger yields in Pb--Pb to those in pp collisions, $I_{\mathrm{AA}}$, is
measured on the near and away side for the $0$--$10$\% most central Pb--Pb
collisions. On the away side, the per-trigger yields in Pb--Pb are strongly
suppressed to the level of $I_{\mathrm{AA}} \approx 0.6$ for
$p_{\mathrm{T}}^{\rm assoc} > 3~\mathrm{GeV}/c$, while with decreasing momenta
an enhancement develops reaching about $5$ at low $p_{\mathrm{T}}^{\rm assoc}$.
On the near side, an enhancement of $I_{\mathrm{AA}}$ between $1.2$ at the
highest to $1.8$ at the lowest $p_{\mathrm{T}}^{\rm assoc}$ is observed. The
data are compared to parton-energy-loss predictions of the JEWEL and AMPT event
generators, as well as to a perturbative QCD calculation with medium-modified
fragmentation functions. All calculations qualitatively describe the away-side
suppression at high $p_{\mathrm{T}}^{\rm assoc}$. Only AMPT captures the
enhancement at low $p_{\mathrm{T}}^{\rm assoc}$, both on the near and away
side. However, it also underpredicts $I_{\mathrm{AA}}$ above $5$ GeV/$c$, in
particular on the near-side.


title:
Capacity-achieving and Flicker-free FEC coding scheme for Dimmable
  Visible Light Communication Based on Polar Codes

abstract:
  Visible light communication (VLC) could provide short-range optical wireless
communication together with illumination using LED lighting. However,
conventional forward error correction (FEC) codes for reliable communication do
not have the features for dimming support and flicker mitigation which are
required in VLC for the main functionality of lighting. Therefore, auxiliary
coding techniques are usually needed, which eventually reduce the coding
efficiency and increase the complexity. In this paper, a polar codes-based FEC
coding scheme for dimmable VLC is proposed to increase the coding efficiency
and simplify the coding structure. Experimental results show that the proposed
scheme has the following advantages: 1) equal probability of 1's and 0's in
codewords, which is inherently supporting 50% dimming balance; 2) short run
length property (about 90% bits have runs shorter than 5) which can avoid
flickers and additional run-length limited line coding; 3) higher coding
efficiency about twofold than that of other coding schemes; 4) capacity
achieving error correction performance with low-complexity encoding and
decoding, which is about 3 dB higher coding gain than that of RS(64,32) in IEEE
standard for dimming ratio 50% and about 1 dB higher coding gain than that of
LDPC codes for dimming ratio 25% (or 75%).


title:
First-principles phase stability, bonding, and electronic structure of
  actinide metals

abstract:
  The actinide elemental metals are scare, often toxic and radio active,
causing challenges for both experiments and theory while offering fascinating
physics. For practical purposes they are the prevalent building blocks for
materials where nuclear properties are of interest. Here, however, we are
focusing on fundamental properties of the actinides related to their electronic
structure and characteristic bonding in the condensed state. The series of
actinides is naturally divided into two segments. First, the set of lighter
actinides thorium through plutonium, often referred to as the early actinides,
display variations of their atomic volume reminiscent of transition metals
suggesting a gradual occupation of bonding 5f states. Second, the heavier (or
late) actinides, Am and onwards, demonstrate a volume behavior comparable to
the rare-earth metals thus implying nonbonding 5f states. Arguably, one can
distinguish plutonium metal as special case lying between these two subsets
because it shares some features from both. Therefore, we discuss the early
actinides, plutonium metal, and the late actinides separately applying
first-principles density-functional-theory (DFT) calculations. The analysis
includes successes and failures of the theory to describe primarily phase
stability, bonding, and electronic structure.


title:
Empirical Null Estimation using Discrete Mixture Distributions and its
  Application to Protein Domain Data

abstract:
  In recent mutation studies, analyses based on protein domain positions are
gaining popularity over gene-centric approaches since the latter have
limitations in considering the functional context that the position of the
mutation provides. This presents a large-scale simultaneous inference problem,
with hundreds of hypothesis tests to consider at the same time. This paper aims
to select significant mutation counts while controlling a given level of Type I
error via False Discovery Rate (FDR) procedures. One main assumption is that
there exists a cut-off value such that smaller counts than this value are
generated from the null distribution. We present several data-dependent methods
to determine the cut-off value. We also consider a two-stage procedure based on
screening process so that the number of mutations exceeding a certain value
should be considered as significant mutations. Simulated and protein domain
data sets are used to illustrate this procedure in estimation of the empirical
null using a mixture of discrete distributions.


title: Thermodynamics of the Fermi gas in a quantum well

abstract:
  For the ideal Fermi gas that fills a quantum well confined by two parallel
planes, there are calculated the thermodynamic characteristics in general form
for arbitrary temperatures, namely: the thermodynamic potential, energy,
entropy, equations of state, heat capacities and compressibilities. The
distance between planes is considered as an additional thermodynamic variable.
Owing to the anisotropy, the pressure of the Fermi gas along and transverse to
the planes is different, so that the system is characterized by two equations
of state and a set of different heat capacities. Limiting cases of low and high
temperatures are considered. The temperature dependencies of the entropy and
heat capacities at low temperatures remain linear, just as in the volume case,
and their dependencies on the chemical potential and density undergo jumps at
the beginning of the filling of new discrete levels. It is shown that the
behavior of thermodynamic quantities with the distance between plates can be
either oscillating or monotonic, depending on what quantity is assumed to be
fixed: the volume or surface density. For high temperatures the corrections to
thermodynamic quantities are obtained, which are proportional to the ratio of
the thermal de Broglie wavelength to the distance between planes.


title: Embedded SML using the MLton compiler

abstract:
  In this extended abstract we present our current work on leveraging Standard
ML for developing embedded and real-time systems. Specifically we detail our
experiences in modifying MLton, a whole program, optimizing compiler for
Standard ML, for use in such contexts. We focus primarily on the language
runtime, re-working the threading subsystem and garbage collector, as well as
necessary changes for integrating MLton generated programs into a light weight
operating system kernel. We compare and contrast these changes to our previous
work on extending MLton for multicore systems, which focused around acheiving
scalability.


title:
Computing log-likelihood and its derivatives for restricted maximum
  likelihood methods

abstract:
  Recent large scale genome wide association analysis involves large scale
linear mixed models. Quantifying (co)-variance parameters in the mixed models
with a restricted maximum likelihood method results in a score function which
is the first derivative of a log-likelihood. To obtain a statistically
efficient estimate of the variance parameters, one needs to find the root of
the score function via the Newton method. Most elements of the Jacobian matrix
of the score involve a trace term of four parametric matrix-matrix
multiplications. It is computationally prohibitively for large scale data sets.
By a serial matrix transforms and an averaged information splitting technique,
an approximate Jacobian matrix can be obtained by splitting the average of the
Jacobian matrix and its expected value. In the approximated Jacobian, its
elements only involve Four matrix vector multiplications which can be
efficiently evaluated by solving sparse linear systems with the multi-frontal
factorization method.


title:
Competing nematic interactions in a generalized XY model in two and
  three dimensions

abstract:
  We study a generalization of the XY model with an additional nematic-like
term through extensive numerical simulations and finite-size techniques, both
in two and three dimensions. While the original model favors local alignment,
the extra term induces angles of $2\pi/q$ between neighboring spins. We focus
here on the $q=8$ case (while presenting new results for other values of $q$ as
well) whose phase diagram is much richer than the well known $q=2$ case. In
particular, the model presents not only continuous, standard transitions
between Berezinskii-Kosterlitz-Thouless (BKT) phases as in $q=2$, but also
infinite order transitions involving intermediate, competition driven phases
absent for $q=2$ and 3. Besides presenting multiple transitions, our results
show that having vortices decoupling at a transition is not a suficient
condition for it to be of BKT type.


title: Coupled K\"ahler-Einstein metrics

abstract:
  We propose new types of canonical metrics on K\"ahler manifolds, called
coupled K\"ahler-Einstein metrics, generalizing K\"ahler-Einstein metrics. We
prove existence and uniqueness results in the cases when the canonical bundle
is ample and when the manifold is K\"ahler-Einstein Fano. In the Fano case we
also prove that existence of coupled K\"ahler-Einstein metrics imply a certain
algebraic stability condition, generalizing $K$-polystability.


title:
Superconductivity on a Quasiperiodic Lattice: Extended-to-Localized
  Crossover of Cooper Pairs

abstract:
  We study a possible superconductivity in quasiperiodic systems, by portraying
the issue within the attractive Hubbard model on a Penrose lattice. Applying a
real-space dynamical mean-field theory to the model consisting of 4181 sites,
we find a superconducting phase at low temperatures. Reflecting the
nonperiodicity of the Penrose lattice, the superconducting state exhibits an
inhomogeneity. According to the type of the inhomogeneity, the superconducting
phase is categorized into three different regions which cross over each other.
Among them, the weak-coupling region exhibits spatially extended Cooper pairs,
which are nevertheless distinct from the conventional pairing of two electrons
with opposite momenta.


title:
Dynamics of atomic spin-orbit-state wave packets produced by short-pulse
  laser photodetachment

abstract:
  We analyse the experiment by Hultgren et al. [Phys. Rev. A {\bf 87}, 031404
(2013)] on orbital alignment and quantum beats in coherently excited atomic
fine-structure manifolds produced by short-pulse laser photodetachment of
C$^-$, Si$^-$ and Ge$^-$ negative ions, and derive a formula that describes the
beats. Analysis of the experimental data enables us to extract the non-coherent
background contribution for each species, and indicates the need for a full
density matrix treatment of the problem.


title:
Nature of the soft ULX in NGC 247: super-Eddington outflow and
  transition between the supersoft and soft ultraluminous regimes

abstract:
  We report on XMM-Newton/Chandra/Swift/HST observations of the ultraluminous
X-ray source (ULX) in NGC 247, which is found to make transitions between the
supersoft ultraluminous (SSUL) regime with a spectrum dominated by a cool
($\sim 0.1$ keV) blackbody component and the soft ultraluminous (SUL) regime
with comparable luminosities shared by the blackbody and power-law components.
Multi-epoch observations revealed an anti-correlation between the blackbody
radius and temperature, $R_{\rm bb} \propto T_{\rm bb}^{-2.8 \pm 0.3}$, ruling
out a standard accretion disk as the origin of the soft X-ray emission. The
soft X-ray emission is much more variable on both short and long timescales in
the SSUL regime than in the SUL regime. We suggest that the SSUL regime may be
an extension of the ultraluminous state toward the high accretion end, being an
extreme case of the SUL regime, with the blackbody emission arising from the
photosphere of thick outflows and the hard X-rays being emission leaked from
the embedded accretion disk via the central low-density funnel or advected
through the wind. However, the scenario that the supersoft ULXs are standard
ULXs viewed nearly edge-on cannot be ruled out. Flux dips on a timescale of 200
s were observed. The dips cannot be explained by an increase of absorption, but
could be due to the change of accretion rate or related to thermal fluctuations
in the wind or disk. The optical emission of NGC 247 ULX exhibits a blackbody
spectrum at a temperature of 19,000 K with a radius of 20 $R_\odot$, likely
arising from an OB supergiant companion star.


title: Optical source of individual pairs of color-conjugated photons

abstract:
  We demonstrate that Kerr nonlinearity in optical circuits can lead to both
resonant four-wave mixing and photon blockade, which can be used for high-yield
generation of high-fidelity individual photon pairs with conjugated
frequencies. We propose an optical circuit, which, in the optimal pulsed-drive
regime, would produce photon pairs at the rate up to $10^5s^{-1}$ (0.5 pairs
per pulse) with $g^{(2)}<10^{-2}$ for one of the conjugated frequencies. We
show that such a scheme can be utilised to generate color-entangled photons.


title:
Analysis of fluid velocity vector field divergence $\nabla\cdot\vec{u}$
  in function of variable fluid density $\rho(\vec{x},t)\neq const$ and
  conditions for vanishing viscosity of compressible Navier-Stokes equations

abstract:
  In this paper, we perform analysis of the fluid velocity vector field
divergence $\nabla \cdot \vec{u}$ derived from the continuity equation, and we
explore its application in the Navier-Stokes equations for compressible fluids
$\rho (\vec{x},t)\ne const$, occupying all of $\vec{x}\in R^{3} $ space at any
$t\geq 0$. The resulting velocity vector field divergence $\nabla \cdot
\vec{u}=-\frac{1}{\rho } (\frac{\partial \rho }{\partial t} +\vec{u}\cdot
\nabla \rho )$ is a direct consequence of the fluid density rate of change over
time $\frac{\partial \rho }{\partial t}$ and over space $\nabla \rho $, in
addition to the fluid velocity vector field $\vec{u}(\vec{x},t)$ and the fluid
density $\rho (\vec{x},t)$ itself. We derive the conditions for the
divergence-free fluid velocity vector field $\nabla \cdot \vec{u}=0$ in
scenarios when the fluid density is not constant $\rho(\vec{x},t)\neq const$
over space nor time, and we analyze scenarios of the non-zero divergence
$\nabla \cdot \vec{u}\ne 0$. We apply the statement for divergence in the
Navier-Stokes equation for compressible fluids, and we deduct the condition for
vanishing (zero) viscosity term of the compressible Navier-Stokes equation:
$\nabla (\frac{1}{\rho } (\frac{\partial \rho }{\partial t} +\vec{u}\cdot
\nabla \rho ))=-3\Delta \vec{u}$. In addition to that, we derive even more
elementary condition for vanishing viscosity, stating that vanishing viscosity
is triggered once scalar function $d(\vec{x},t)=-\frac{1}{\rho }
(\frac{\partial \rho }{\partial t} +\vec{u}\cdot \nabla \rho )$ is harmonic
function. Once that condition is satisfied, the viscosity related term of the
Navier-Stokes equations for compressible fluids equals to zero, which is known
as related to turbulent fluid flows.


title:
A Demonstration of Spectral Level Reconstruction of Intrinsic $B$-mode
  Power

abstract:
  We investigate the prospects and consequences of the spectral level
reconstruction of primordial $B$-mode power by solving the systems of linear
equations assuming that the lensing potential together with the lensed
polarization spectra are already in hand. We find that this reconstruction
technique may be very useful to have an estimate of the amplitude of primordial
gravity waves or more specifically the value of tensor to scalar ratio. We also
see that one can have cosmic variance limited reconstruction of the intrinsic
$B$-mode power up to few hundred multipoles ($\ell\sim500$) which is more than
sufficient to have an estimate of the tensor to scalar ratio. Since the small
scale cosmic microwave background (CMB henceforth) anisotropies are not sourced
by the primordial gravity waves generated during inflation. We also find that
the impact of instrumental noise may be bypassed within this reconstruction
algorithm. A simple demonstration for the nullification of the instrumental
noise anticipating COrE like futuristic space mission complemented with Planck
2013 cosmology has been presented.


title: Skyrmion Hall Effect Revealed by Direct Time-Resolved X-Ray Microscopy

abstract:
  Magnetic skyrmions are highly promising candidates for future spintronic
applications such as skyrmion racetrack memories and logic devices. They
exhibit exotic and complex dynamics governed by topology and are less
influenced by defects, such as edge roughness, than conventionally used domain
walls. In particular, their finite topological charge leads to a predicted
"skyrmion Hall effect", in which current-driven skyrmions acquire a transverse
velocity component analogous to charged particles in the conventional Hall
effect. Here, we present nanoscale pump-probe imaging that for the first time
reveals the real-time dynamics of skyrmions driven by current-induced spin
orbit torque (SOT). We find that skyrmions move at a well-defined angle
{\Theta}_{SH} that can exceed 30{\deg} with respect to the current flow, but in
contrast to theoretical expectations, {\Theta}_{SH} increases linearly with
velocity up to at least 100 m/s. We explain our observation based on internal
mode excitations in combination with a field-like SOT, showing that one must go
beyond the usual rigid skyrmion description to unravel the dynamics.


title: The Poincar\'e problem in the dicritical case

abstract:
  We develop a study on local polar invariants of planar complex analytic
foliations at $(\mathbb{C}^{2},0)$, which leads to the characterization of
second type foliations and of generalized curve foliations, as well as a
description of the $GSV$-index. We apply it to the Poincar\'e problem for
foliations on the complex projective plane $\mathbb{P}^{2}_{\mathbb{C}}$,
establishing, in the dicritical case, conditions for the existence of a bound
for the degree of an invariant algebraic curve $S$ in terms of the degree of
the foliation $\mathcal{F}$. We characterize the existence of a solution for
the Poincar\'e problem in terms of the structure of the set of local
separatrices of $\mathcal{F}$ over the curve $S$. Our method, in particular,
recovers the known solution for the non-dicritical case, ${\rm deg}(S) \leq
{\rm deg}(\mathcal{F}) + 2$.


title:
Pattern formation in polymerising actin flocks: spirals, spots and waves
  without nonlinear chemistry

abstract:
  We propose a model solely based on actin treadmilling and polymerisation
which describes many characteristic states of actin wave formation: spots,
spirals and travelling waves. In our model, as in experiments on cell
recovering motility following actin depolymerisation, we choose an isotropic
low density initial condition; polymerisation of actin filaments then raises
the density towards the Onsager threshold where they align. We show that this
alignment, in turn, destabilizes the isotropic phase and generically induces
transient actin spots or spirals as part of the dynamical pathway towards a
polarized phase which can either be uniform or consist of a series of
actin-wave trains (flocks). Our results uncover a universal route to actin wave
formation in the absence of any system specific nonlinear biochemistry, and it
may help understand the mechanism underlying the observation of actin spots and
waves in vivo. They also suggest a minimal setup to design similar patterns in
vitro.


title:
Discrete Gauge Groups in F-theory Models on Genus-One Fibered Calabi-Yau
  4-folds without Section

abstract:
  We determine the discrete gauge symmetries that arise in F-theory
compactifications on examples of genus-one fibered Calabi-Yau 4-folds without a
section. We construct genus-one fibered Calabi-Yau 4-folds using Fano
manifolds, cyclic 3-fold covers of Fano 4-folds, and Segre embeddings of
products of projective spaces. Discrete $\mathbb{Z}_5$, $\mathbb{Z}_4$,
$\mathbb{Z}_3$ and $\mathbb{Z}_2$ symmetries arise in these constructions. We
introduce a general method to obtain multisections for several constructions of
genus-one fibered Calabi-Yau manifolds. The pullbacks of hyperplane classes
under certain projections represent multisections to these genus-one
fibrations. We determine the degrees of these multisections by computing the
intersection numbers with fiber classes. As a result, we deduce the discrete
gauge symmetries that arise in F-theory compactifications. This method applies
to various Calabi-Yau genus-one fibrations.


title:
Yet Another Condition for Absence of Collisions for Competing Brownian
  Particles

abstract:
  Consider a finite system of rank-based competing Brownian particles, where
the drift and diffusion of each particle depend only on its current rank
relative to other particles. We present a simple sufficient condition for
absence of multiple collisions of a given order, continuing the earlier work by
Bruggeman and Sarantsev (2015). Unlike in that paper, this new condition works
even for infinite systems.


title: Bulk graphanes synthesized from benzene and pyridine

abstract:
  We report a high-pressure high-temperature synthesis of several
millimeter-sized samples of bulk graphanes with the composition C-H(D) from
benzene and graphene-derivative C-H-N$_{0.2}$ from pyridine. X-ray diffraction,
transmission electron microscopy, and infrared spectroscopy of new materials
reveal relatively large (several nanometers in size) crystalline grains of an
sp3-bonded graphane lattice (3-cycle-4-step, the orthorhombic structure with
Pbca space group and parameters a = 9.5-9.8, b = 8.9-9.1, c = 17.1-17.3 $\AA$).
The main hydrogen groups in samples are C-H groups connected by aliphatic
bonds. The synthesized graphanes at atmospheric pressure are stable up to 500
C. The macroscopic density of CH samples is 1.5-1.57 g cm$^{-3} $ and the
refractive index is 1.78-1.80. The absorption spectra of samples with a high
degree of crystallization exhibits a weak absorption maximum at 2.8 eV, which
is responsible for the yellow-orange color, large absorption maximum at 4 eV
and an absorption edge associated with the width of the optical gap at 5.2 eV.
The bulk modulus (30-37 GPa) and shear modulus (15-18 GPa) of the fabricated
samples, as well as their hardness (1-1.5 GPa), are about twice as high as the
respective values for polycrystalline graphite. The solution of metalorganic
complexes in benzene and pyridine makes it possible to obtain doped graphanes,
which can have extraordinary electron transport and magnetic properties.


title: Edge Mode Amplification in Disordered Elastic Networks

abstract:
  We study theoretically and numerically the propagation of a displacement
field imposed at the edge of a disordered elastic material. While some modes
decay with some inverse penetration depth $\kappa$, other exponentially {\it
amplify} with rate $|\kappa|$, where $\kappa$'s are Lyapounov exponents
analogous to those governing electronic transport in a disordered conductors.
We obtain an analytical approximation for the full distribution $g(\kappa)$,
which decays exponentially for large $|\kappa|$ and is finite when
$\kappa\rightarrow0$. Our analysis shows that isostatic materials generically
act as levers with possibly very large gains, suggesting a novel principle to
design molecular machines that behave as elastic amplifiers.