title: Software Quality - Traditional vs. Agile: an Empirical Investigation

abstract:
  It is well known that the software process impacts the quality of the
resulting product. There are also anecdotal claims that agile processes result
in higher level of quality than traditional methodologies. However, still solid
evidence of this is missing. This work reports in an empirical analysis of the
correlation between software process and software quality with specific
reference to agile and traditional processes. More than 100 software developers
and engineers from 21 countries have been surveyed with an online
questionnaire. We have used the percentage of satisfied customers estimated by
the software developers and engineers as the main dependent variable. The
results evidence some interesting patterns: architectural styles may not have a
significant influence on quality, agile methodologies might result in happier
customers, larger companies and shorter projects seems to produce better
products.


title: Skyrmion production on demand by homogeneous DC currents

abstract:
  Topological magnetic textures - like skyrmions - have become a major player
in the design of next-generation magnetic storage technology due to their
stability and the control of their motion by ultra-low current densities. A
major challenge to develop this new skyrmion-based technology is to achieve the
controlled and deterministic creation of magnetic skyrmions without the need of
complex setups. We demonstrate a solution to this challenge by showing how to
create skyrmions and other magnetic textures in ferromagnetic thin films by
means of a homogeneous DC current and without requiring Dzyaloshinskii-Moriya
interactions. This is possible by exploiting a static loss of stability arising
from the interplay of current-induced spin-transfer torque and a spatially
inhomogeneous magnetization, which can be achieved, e.g., by locally
engineering the anisotropy, the magnetic field, or other magnetic interactions.
The magnetic textures are created controllably, efficiently, and periodically
with a period that can be tuned by the applied current strength. We propose
specific experimental setups realizable with simple materials, such as cobalt
based materials, to observe the periodic formation of skyrmions. We show that
adding chiral interactions will not influence the basics of the generations but
then influence the consequent dynamics with respect to the stabilization of
topological textures. Our findings allow for the production of skyrmions on
demand in simple ferromagnetic thin films by homogeneous DC currents.


title:
The energy budget of stellar magnetic fields: comparing non-potential
  simulations and observations

abstract:
  The magnetic geometry of the surface magnetic fields of more than 55 cool
stars have now been mapped using spectropolarimetry. In order to better
understand these observations, we compare the magnetic field topology at
different surface scale sizes of observed and simulated cool stars. For ease of
comparison between the high-resolution non-potential magnetofrictional
simulations and the relatively low-resolution observations, we filter out the
small-scale field in the simulations using a spherical harmonics decomposition.
We show that the large-scale field topologies of the solar-based simulations
produce values of poloidal/toroidal fields and fractions of energy in
axisymmetric modes that are similar to the observations. These global
non-potential evolution model simulations capture key magnetic features of the
observed solar-like stars through the processes of surface flux transport and
magnetic flux emergence. They do not, however, reproduce the magnetic field of
M-dwarfs or stars with dominantly toroidal field. Furthermore, we analyse the
magnetic field topologies of individual spherical harmonics for the simulations
and discover that the dipole is predominately poloidal, while the quadrupole
shows the highest fraction of toroidal fields. Magnetic field structures
smaller than a quadrupole display a fixed ratio between the poloidal and
toroidal magnetic energies.


title:
Squared width and profile of the confining flux tube in the U(1) LGT in
  3D

abstract:
  The dual formulation of the compact U(1) lattice gauge theory in three
spacetime dimensions allows to finely study the squared width and the profile
of the confining flux tube on a wide range of physical interquark distances.
The results obtained in Monte Carlo simulations are compared with the
predictions of the effective bosonic-string model and with the dual
superconductor model. While the former fails at describing the data from a
quantitative point of view, the latter is in good agreement with it. An
interpretation of these results is proposed in light of the particular features
of the U(1) lattice gauge theory in 3D and a comparison with non-Abelian gauge
theories in four spacetime dimensions is discussed.


title:
A prescription for transforming polarization states of light using two
  quarter waveplates

abstract:
  It is well known that state transformation from one polarization state to
another can be achieved with a minimal gadget consisting of two quarter
waveplates. A constructive, geometric approach is presented, which provides a
direct prescription for the fast axis setting of the waveplates to transform
any completely polarized states of light to any other, including orthogonal
ones.


title:
On the nature of the magnetic Rayleigh-Taylor instability in
  Astrophysical Plasma: The case of uniform magnetic field strength

abstract:
  The magnetic Rayleigh-Taylor instability has been shown to play a key role in
many astrophysical systems. The equation for the growth rate of this
instability in the incompressible limit, and the most-unstable mode that can be
derived from it, are often used to estimate the strength of the magnetic field
that is associated with the observed dynamics. However, there are some issues
with the interpretations given. Here we show that the class of most unstable
modes $k_u$ for a given $\theta$, the class of modes often used to estimate the
strength of the magnetic field from observations, for the system leads to the
instability growing as $\sigma^2=1/2 A g k_u$, a growth rate which is
independent of the strength of the magnetic field and which highlights that
small scales are preferred by the system, but not does not give the fastest
growing mode for that given $k$. We also highlight that outside of the
interchange ($\mathbf{k}\cdot\mathbf{B}=0$) and undular ($\mathbf{k}$ parallel
to $\mathbf{B}$) modes, all the other modes have a perturbation pair of the
same wavenumber and growth rate that when excited in the linear regime can
result in an interference pattern that gives field aligned filamentary
structure often seen in 3D simulations. The analysis was extended to a sheared
magnetic field, where it was found that it was possible to extend the results
for a non-sheared field to this case. We suggest that without magnetic shear it
is too simplistic to be used to infer magnetic field strengths in astrophysical
systems.


title:
GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM)
  survey I: A low-frequency extragalactic catalogue

abstract:
  Using the Murchison Widefield Array (MWA), the low-frequency Square Kilometre
Array (SKA1 LOW) precursor located in Western Australia, we have completed the
GaLactic and Extragalactic All-sky MWA (GLEAM) survey, and present the
resulting extragalactic catalogue, utilising the first year of observations.
The catalogue covers 24,831 square degrees, over declinations south of
$+30^\circ$ and Galactic latitudes outside $10^\circ$ of the Galactic plane,
excluding some areas such as the Magellanic Clouds. It contains 307,455 radio
sources with 20 separate flux density measurements across 72--231MHz, selected
from a time- and frequency- integrated image centred at 200MHz, with a
resolution of $\approx 2$'. Over the catalogued region, we estimate that the
catalogue is 90% complete at 170mJy, and 50% complete at 55mJy, and large areas
are complete at even lower flux density levels. Its reliability is 99.97% above
the detection threshold of $5\sigma$, which itself is typically 50mJy. These
observations constitute the widest fractional bandwidth and largest sky area
survey at radio frequencies to date, and calibrate the low frequency flux
density scale of the southern sky to better than 10%. This paper presents
details of the flagging, imaging, mosaicking, and source
extraction/characterisation, as well as estimates of the completeness and
reliability. All source measurements and images are available online
(http://www.mwatelescope.org/science/gleam-survey). This is the first in a
series of publications describing the GLEAM survey results.


title:
Quantum state readout of individual quantum dots by electrostatic force
  detection

abstract:
  Electric charge detection by atomic force microscopy (AFM) with single-
electron resolution (e-EFM) is a promising way to investigate the electronic
level structure of individual quantum dots (QD). The oscillating AFM tip
modulates the energy of the QDs, causing single electrons to tunnel between QDs
and an electrode. The resulting oscillating electrostatic force changes the
resonant frequency and damping of the AFM cantilever, enabling electrometry
with a single-electron sensitivity. Quantitative electronic level spectroscopy
is possible by sweeping the bias voltage. Charge stability diagram can be
obtained by scanning the AFM tip around the QD. e-EFM technique enables to
investigate individual colloidal nanoparticles and self- assembled QDs without
nanoscale electrodes. e-EFM is a quantum electromechanical system where the
back-action of a tunneling electron is detected by AFM; it can also be
considered as a mechanical analog of admittance spectroscopy with a radio
frequency resonator, which is emerging as a promising tool for quantum state
readout for quantum computing. In combination with the topography imaging
capability of the AFM, e-EFM is a powerful tool for investigating new nanoscale
material systems which can be used as quantum bits.


title:
Matrix product construction for Koornwinder polynomials and fluctuations
  of the current in the open ASEP

abstract:
  Starting from the deformed current-counting transition matrix for the open
boundary ASEP, we prove that with a further deformation, the symmetric
Koornwinder polynomials for partitions with equal row lengths appear as the
normalisation of the twice deformed ground state. We give a matrix product
construction for this ground state and the corresponding symmetric Koornwinder
polynomials. Based on the form of this construction and numerical evidence, we
conjecture a relation between the generating function of the cumulants of the
current, and a certain limit of the symmetric Koornwinder polynomials.

categories: math-ph cond-mat.stat-mech math.MP math.RT


title:
Using radiative energy losses to constrain the magnetisation and
  magnetic reconnection rate at the base of black hole jets

abstract:
  We calculate the severe radiative energy losses which occur at the base of
black hole jets using a relativistic fluid jet model, including in-situ
acceleration of non-thermal leptons by magnetic reconnection. Our results
demonstrate that including a self-consistent treatment of radiative energy
losses is necessary to perform accurate MHD simulations of powerful jets and
that jet spectra calculated via post-processing are liable to vastly
overestimate the amount of non-thermal emission. If no more than 95% of the
initial total jet power is radiated away by the plasma travels as it travels
along the length of the jet, we can place a lower bound on the magnetisation of
the jet plasma at the base of the jet. For typical powerful jets, we find that
the plasma at the jet base is required to be highly magnetised, with at least
10,000 times more energy contained in magnetic fields than in non-thermal
leptons. Using a simple power-law model of magnetic reconnection, motivated by
simulations of collisionless reconnection, we determine the allowed range of
the large-scale average reconnection rate along the jet, by restricting the
total radiative energy losses incurred and the distance at which the jet first
comes into equipartition. We calculate analytic expressions for the cumulative
radiative energy losses due to synchrotron and inverse-Compton emission along
jets, and derive analytic formulae for the constraint on the initial
magnetisation.


title: Agencies and Science-Experiment Risk

abstract:
  There is a curious absence of legal constraints on U.S. government agencies
undertaking potentially risky scientific research. Some of these activities may
present a risk of killing millions or even destroying the planet. Current law
leaves it to agencies to decide for themselves whether their activities fall
within the bounds of acceptable risk. This Article explores to what extent and
under what circumstances the law ought to allow private actions against such
non-regulatory agency endeavors. Engaging with this issue is not only
interesting in its own right, it allows us to test fundamental concepts of
agency competence and the role of the courts.
  Two case studies provide a foundation for discussion: NASA's use of plutonium
power supplies on spacecraft, which critics say could cause millions of cancers
in the event of atmospheric disintegration, and a Department of Energy
particle-collider experiment (the RHIC, or Relativistic Heavy Ion Collider)
that allegedly poses a small risk of collapsing the Earth (via a "killer
strangelet"). These extreme examples serve as a test-bed for applying insights
from neoclassical economics, behavioral economics, risk-management studies, and
cognitive psychology. The resulting analysis suggests that in
low-probability/high-harm scenarios, agencies are likely to do a poor job of
judging the acceptability of risk to the public. Instead, generalist judges
working in a common-law vein may have surprising advantages. This in turns
suggests that under certain circumstances the government should be subject to
legal action that provides non-deferential review of discretionary agency
actions that are non-regulatory in nature.


title:
Evidence for vacuum birefringence from the first optical polarimetry
  measurement of the isolated neutron star RX\, J1856.5$-$3754

abstract:
  The "Magnificent Seven" (M7) are a group of radio-quiet Isolated Neutron
Stars (INSs) discovered in the soft X-rays through their purely thermal surface
emission. Owing to the large inferred magnetic fields ($B\approx 10^{13}$ G),
radiation from these sources is expected to be substantially polarised,
independently on the mechanism actually responsible for the thermal emission. A
large observed polarisation degree is, however, expected only if
quantum-electrodynamics (QED) polarisation effects are present in the
magnetised vacuum around the star. The detection of a strongly linearly
polarised signal would therefore provide the first observational evidence of
QED effects in the strong-field regime. While polarisation measurements in the
soft X-rays are not feasible yet, optical polarisation measurements are within
reach also for quite faint targets, like the M7 which have optical counterparts
with magnitudes $\approx 26$--$28$. Here, we report on the measurement of
optical linear polarisation for the prototype, and brightest member, of the
class, RX\, J1856.5$-$3754 ($V\sim 25.5$), the first ever for one of the M7,
obtained with the Very Large Telescope. We measured a polarisation degree
$\mathrm{P.D.} =16.43\% \pm5.26\%$ and a polarisation position angle
$\mathrm{P.A.}=145\fdg39\pm9\fdg44$, computed east of the North Celestial
Meridian. The $\mathrm{P.D.}$ that we derive is large enough to support the
presence of vacuum birefringence, as predicted by QED.


title:
Inter-event correlations from avalanches hiding below the detection
  threshold

abstract:
  Numerous systems ranging from deformation of materials to earthquakes exhibit
bursty dynamics, which consist of a sequence of events with a broad event size
distribution. Very often these events are observed to be temporally correlated
or clustered, evidenced by power-law distributed waiting times separating two
consecutive activity bursts. We show how such inter-event correlations arise
simply because of a finite detection threshold, created by the limited
sensitivity of the measurement apparatus, or used to subtract background
activity or noise from the activity signal. Data from crack propagation
experiments and numerical simulations of a non-equilibrium crack line model
demonstrate how thresholding leads to correlated bursts of activity by
separating the avalanche events into sub-avalanches. The resulting temporal
sub-avalanche correlations are well-described by our general scaling
description of thresholding-induced correlations in crackling noise.


title:
Social Groups and Pedestrian Crowds: Experiment on Dyads in a Counter
  Flow Scenario

abstract:
  The calibration and validation of pedestrian simulations require the
acquisition of empirical evidences of human behaviour. The current work
presents the results of an experiment focused on the potentially combined
effect of counter flow and grouping on pedestrian dynamics. In particular, we
focused on: (i) four different configurations of flow ratio (the rate between
the minor flow and the total flow in bidirectional scenarios); (ii) dyads, as
the most frequently observed and basic social groups of crowds. Results showed
that the increase of flow ratio negatively impacted the speed of pedestrians.
Dyads walked significantly slower than singletons, due to the difficulty in
movement coordination among group members (proxemics) in case of counter flow.
The collected results represent an useful contribution towards the validation
of pedestrian simulations.


title:
Highly efficient frequency conversion with bandwidth compression of
  quantum light

abstract:
  Hybrid quantum networks rely on efficient interfacing of dissimilar quantum
nodes, since elements based on parametric down-conversion sources, quantum
dots, color centres or atoms are fundamentally different in their frequencies
and bandwidths. While pulse manipulation has been demonstrated in very
different systems, to date no interface exists that provides both an efficient
bandwidth compression and a substantial frequency translation at the same time.
Here, we demonstrate an engineered sum-frequency-conversion process in Lithium
Niobate that achieves both goals. We convert pure photons at telecom
wavelengths to the visible range while compressing the bandwidth by a factor of
7.47 under preservation of non-classical photon-number statistics. We achieve
internal conversion efficiencies of 75.5%, significantly outperforming spectral
filtering for bandwidth compression. Our system thus makes the connection
between previously incompatible quantum systems as a step towards usable
quantum networks.


title: Transition from the C3-dominated discharge to the sooting plasma

abstract:
  Mass spectrometry and photoemission spectroscopy of a graphite hollow cathode
source identify the parameters of the transition from the C(3) dominated
discharge to the sooting plasma. The transition is a function of the shape and
profile of a special cusp magnetic field which is a function of radius and
azimuth angle, the geometry of the source, the discharge current, and pressure.
Characteristic atomic and molecular emission lines and bands in the C(3)
discharge transform into broad bands emitted by the excited soot. We identify
four prominent emission bands between 300 to 400 nm to be the hallmark of the
sooting plasma.


title: Event generator tuning using Bayesian optimization

abstract:
  Monte Carlo event generators contain a large number of parameters that must
be determined by comparing the output of the generator with experimental data.
Generating enough events with a fixed set of parameter values to enable making
such a comparison is extremely CPU intensive, which prohibits performing a
simple brute-force grid-based tuning of the parameters. Bayesian optimization
is a powerful method designed for such black-box tuning applications. In this
article, we show that Monte Carlo event generator parameters can be accurately
obtained using Bayesian optimization and minimal expert-level physics
knowledge. A tune of the PYTHIA 8 event generator using $e^+e^-$ events, where
20 parameters are optimized, can be run on a modern laptop in just two days.
Combining the Bayesian optimization approach with expert knowledge should
enable producing better tunes in the future, by making it faster and easier to
study discrepancies between Monte Carlo and experimental data.


title:
quantreg.nonpar: An R Package for Performing Nonparametric Series
  Quantile Regression

abstract:
  The R package quantreg.nonpar implements nonparametric quantile regression
methods to estimate and make inference on partially linear quantile models.
quantreg.nonpar obtains point estimates of the conditional quantile function
and its derivatives based on series approximations to the nonparametric part of
the model. It also provides pointwise and uniform confidence intervals over a
region of covariate values and/or quantile indices for the same functions using
analytical and resampling methods. This paper serves as an introduction to the
package and displays basic functionality of the functions contained within.


title: Space-time symmetry is broken

abstract:
  Space-time intervals corresponding to different events on the worldline of
any ponderable object (for example a clock) are time-like. In consequence, in
the analysis of any space-time experiment involving clocks only the region for
$c\Delta t \ge 0$ between the line $\Delta x = 0$ and the light cone projection
$c\Delta t = \Delta x$ of the $c\Delta t$ versus $\Delta x$ Minkowski plot is
physically relevant. This breaks the manifest space-time symmetry of the plot.
A further consequence is the unphysical nature of the `relativity of
simultaneity' and `length contraction' effects of conventional special
relativity theory. The only modification of space-time transformation laws in
passing from Galilean to special relativity is then the replacement of
universal Newtonian time by a universal (position independent) time dilation
effect for moving clocks.


title:
The Contemporary State of Fundamental Physical Research and the Future
  Path to Scientific Knowledge

abstract:
  Classical physics has enabled the acquisition of significant knowledge of the
physical properties of nature on a standard macroscopic scale. These
achievements were driven by use of the causal ontological approach (proposed
originally by Aristotle) to formulate models of physical reality. At the
beginning of the 20th century, however, the physics community began to prefer
models based on a fundamentally different approach to human knowledge.
Copenhagen quantum mechanics (CQM) was used to describe the micro-world. The
special theory of relativity was used to describe the kinematics of objects
moving at high velocity values in both the macroscopic and microscopic regions.
This phenomenological approach to knowledge has been more focused on how things
appear - instead of their actual properties and causal sequence. In the middle
of the 20th century, the causal ontological approach was used to develop a
significant scientific advance: the systematization of fundamental strongly
interacting particles on the basis of unified algebra in three-dimensional
isotopic spin space for spin values 1, 1/2, and 0. However, it was later
strongly deformed under the influence of the phenomenological approach and the
quark model. This paper will show that practically all contemporary theoretical
models of physical reality contain mistakes or unresolved problems. Further
scientific progress can be obtained if (and only if) scientists return to the
successful causal ontological approach and falsification. Classical physics may
be slightly generalized to enable the description of inertia mass increase in
dependence on velocity, replacing the relativity theory and CQM. New
assumptions may then be employed using generalized classical physics (GCP) to
formulate new descriptions of observed phenomena that were previously
inaccurately interpreted and used to promote fundamentally inadequate theories.


title: Distortion Contribution Analysis with the Best Linear Approximation

abstract:
  A Distortion Contribution Analysis (DCA) obtains the distortion at the output
of an analog electronic circuit as a sum of distortion contributions of its
sub-circuits. Similar to a noise analysis, a DCA helps a designer to pinpoint
the actual source of the distortion. Classically, the DCA uses the Volterra
theory to model the circuit and its sub-circuits. This DCA has been proven
useful for small circuits or heavily simplified examples. In more complex
circuits however, the amount of contributions increases quickly, making the
interpretation of the results difficult. In this paper, the Best Linear
Approximation (BLA) is used to perform the DCA instead. The BLA represents the
behaviour of a sub-circuit as a linear circuit with the unmodelled distortion
represented by a noise source. Combining the BLA with a classic noise analysis
yields a DCA that is simple to understand, yet capable to handle complex
excitation signals and complex strongly non-linear circuits.


title: Properties of minimal mutation-infinite quivers

abstract:
  We study properties of minimal mutation-infinite quivers. In particular we
show that every minimal-mutation infinite quiver of at least rank 4 is Louise
and has a maximal green sequence. It then follows that the cluster algebras
generated by these quivers are locally acyclic and hence equal to their upper
cluster algebra. We also study which quivers in a mutation-class have a maximal
green sequence. For any rank 3 quiver there are at most 6 quivers in its
mutation class that admit a maximal green sequence. We also show that for every
rank 4 minimal mutation-infinite quiver there is a finite connected subgraph of
the unlabelled exchange graph consisting of quivers that admit a maximal green
sequence.


title:
Connection between Symmetrical Special Relativity and the Gravitational
  Bose Einstein Condensate of a Gravastar/Dark Energy Star: Are there
  singularities in spacetime like black holes?

abstract:
  We aim to search for a connection between an invariant minimum speed that
breaks down the Lorentz symmetry and the Gravitational Bose Einstein Condensate
(GBEC), which is the central core of a star of gravitating vacuum
(Gravastar/Dark Energy Star) by introducing a cosmological constant into
compact objects. This model was designed to circumvent the embarrassment
generated by the paradoxes of a singularity as the final stage of a
gravitational collapse, by introducing in place of the singularity of event
horizon a spatial-temporal phase transition, a concept with which the causal
structure of Symmetrical Special Relativity (SSR) helps us to elucidate by
providing a quantum interpretation for GBEC and explaining the origin of
anisotropy, which has been introduced in ad-hoc way before in the literature.


title:
Non-existence of solutions for non-autonomous elliptic systems of
  Hamiltonian type

abstract:
  We extend the classical Pohozaev's identity to semilinear elliptic systems of
Hamiltonian type, providing a simpler approach, and a generalization, of the
results of E. Mitidieri [6], R.C.A.M. Van der Vorst [14], and Y. Bozhkov and E.
Mitidieri [1].


title:
The Event-Camera Dataset and Simulator: Event-based Data for Pose
  Estimation, Visual Odometry, and SLAM

abstract:
  New vision sensors, such as the Dynamic and Active-pixel Vision sensor
(DAVIS), incorporate a conventional global-shutter camera and an event-based
sensor in the same pixel array. These sensors have great potential for
high-speed robotics and computer vision because they allow us to combine the
benefits of conventional cameras with those of event-based sensors: low
latency, high temporal resolution, and very high dynamic range. However, new
algorithms are required to exploit the sensor characteristics and cope with its
unconventional output, which consists of a stream of asynchronous brightness
changes (called "events") and synchronous grayscale frames. For this purpose,
we present and release a collection of datasets captured with a DAVIS in a
variety of synthetic and real environments, which we hope will motivate
research on new algorithms for high-speed and high-dynamic-range robotics and
computer-vision applications. In addition to global-shutter intensity images
and asynchronous events, we provide inertial measurements and ground-truth
camera poses from a motion-capture system. The latter allows comparing the pose
accuracy of ego-motion estimation algorithms quantitatively. All the data are
released both as standard text files and binary files (i.e., rosbag). This
paper provides an overview of the available data and describes a simulator that
we release open-source to create synthetic event-camera data.


title:
A microscopic rotational cranking model and its connection to
  conventional cranking and other collective rotational models

abstract:
  A microscopic time-reversal invariant cranking model (MCRM) for nuclear
collective rotation about a single axis and its coupling to intrinsic motion is
derived. The MCRM is derived by transforming the stationary nuclear Schrodinger
equation using a collective rotation-intrinsic product wavefunction, imposing
no constraints on the wavefunction and the nucleon coordinates, and using no
relative co-ordinates. The derivatives of the collective-rotation angle are
defined in terms of a combination of rigid and irrotational collective flows of
the nucleons. The collective wavefunction is chosen to be an eigenstate of the
angular momentum, yielding a MCRM Schrodinger equation for the intrinsic
wavefunction that contains a cranking Coriolis energy term that is linear in
the angular momentum and shear operators, a collective centrifugal energy term,
and a rotation-fluctuation energy term. In absence of the irrotational-flow
component and fluctuation energy term, the MCRM equation reduces to that of the
conventional cranking model (CCRM), but with a dynamic rigid-flow angular
velocity and rigid-flow centrifugal-energy term. The expectation of the angular
momentum operator, which is the sum of the collective rotation angular momentum
and the expectation of the angular momentum in the intrinsic state, would
reduce to that in the CCRM if the collective rotation angular momentum were
small. However, it is shown that, even for the simple case of the anisotropic
harmonic oscillator mean-field potential in , the collective rotation angular
momentum is not small in the current version of the MCRM, and that this problem
needs further study. It is also shown that the MCRM Schrodinger equation is
reducible to the equations of the particle-plus-rotor, phenomenological and
microscopic collective rotation-vibration, and two-fluid semi-classical
collective models.


title:
Collisions of three-dimensional bipolar optical solitons in an array of
  carbon nanotubes

abstract:
  We study interactions of extremely short three-dimensional bipolar
electromagnetic pulses propagating towards each other in an array of
semiconductor carbon nanotubes, along any direction perpendicular to their
axes. The analysis provides a full account of the effects of the nonuniformity
of the pulses' fields along the axes. The evolution of the electromagnetic
field and charge density in the sample is derived from the Maxwell's equations
and the continuity equation, respectively. In particular, we focus on indirect
interaction of the pulses via the action of their fields on the electronic
subsystem of the nanotube array. Changes in the shape of pulses in the course
of their propagation and interaction are analyzed by calculating and
visualizing the distribution of the electric field in the system. The numerical
analysis reveals a possibility of stable post-collision propagation of pulses
over distances much greater than their sizes.


title: Bounded cohomology of discrete groups

abstract:
  Bounded cohomology of groups was first defined by Johnson and Trauber during
the seventies in the context of Banach algebras. As an independent and very
active research field, however, bounded cohomology started to develop in 1982,
thanks to the pioneering paper "Volume and Bounded Cohomology" by M. Gromov,
where the definition of bounded cohomology was extended to deal also with
topological spaces.
  The aim of this monograph is to provide an introduction to bounded cohomology
of discrete groups and of topological spaces. We also describe some
applications of the theory to related active research fields (that have been
chosen according to the taste and the knowledge of the author). The book is
essentially self-contained. Even if a few statements do not appear elsewhere
and some proofs are slighlty different from the ones already available in the
literature, the monograph does not contain original results.
  In the first part of the book we settle the fundamental definitions of the
theory, and we prove some (by now classical) results on low-dimensional bounded
cohomology and on bounded cohomology of topological spaces. Then we describe
how bounded cohomology has proved useful in the study of the simplicial volume
of manifolds, for the classification of circle actions, for the definition and
the description of maximal representations of surface groups, and in the study
of higher rank flat vector bundles (also in relation with the Chern
conjecture).


title: HAWC Upgrade for Multi-TeV {\gamma}-ray Detection

abstract:
  The High Altitude Water Cherenkov (HAWC) high-energy {\gamma}-ray observatory
was completed in march 2015 in central Mexico. The detector, consisting of 300
water tanks, is currently being upgraded to improve its performance at
Multi-TeV energies, with a sparse array of small water Cherenkov tanks. It will
extend the instrumental area by a factor of 4, and enhance the sensitivity at
the highest energies. In this contribution, the current status of the
observatory is presented, as well as the coming upgrade. The electronics and
the readout system for the new sparse array of small water tanks are also
desrcibed, and results from simulations performed to optimize the performance
of the array are discussed.


title: Dynamics of Anti-Proton -- Protons and Anti-Proton -- Nucleus Reactions

abstract:
  A short review of simulation results of anti-proton-proton and
anti-proton-nucleus interactions within the framework of Geant4 FTF (Fritiof)
model is presented. The model uses the main assumptions of the
Quark-Gluon-String Model or Dual Parton Model. The model assumes production and
fragmentation of quark-anti-quark and diquark-anti-diquark strings in the
mentioned interactions. Key ingredients of the model are cross sections of
string creation processes and an usage of the LUND string fragmentation
algorithm. They allow one to satisfactory describe a large set of experimental
data, especially, a strange particle production, Lambda hyperons and K mesons.


title:
Analysis of Tourism Dynamics and Special Events through Mobile Phone
  Metadata

abstract:
  Tourism has been an increasingly important factor in global economy, society
and environment, accounting for a significant share of GDP and labor force.
Policy and research on tourism traditionally rely on surveys and economic
datasets, which are based on small samples and depict tourism dynamics at low
spatial and temporal granularity. Anonymous call detail records (CDRs) are a
novel source of data, showing enormous potential in areas of high societal
value: such as epidemics, poverty, and urban development. This study
demonstrates the added value of using CDRs for the formulation, analysis and
evaluation of tourism strategies, at the national and local levels. In the
context of the European country of Andorra, we use CDRs to evaluate marketing
strategies in tourism, understand tourists' experiences, and evaluate revenues
and externalities generated by touristic events. We do this by extracting novel
indicators in high spatial and temporal resolutions, such as tourist flows per
country of origin, flows of new tourists, tourist revisits, tourist
externalities on transportation congestion, spatial distribution, economic
impact, and profiling of tourist interests. We exemplify the use of these
indicators for the planning and evaluation of high impact touristic events,
such as cultural festivals and sports competitions.


title:
A comparison of the cosmic-ray energy scales of Tunka-133 and
  KASCADE-Grande via their radio extensions Tunka-Rex and LOPES

abstract:
  The radio technique is a promising method for detection of cosmic-ray air
showers of energies around $100\,$PeV and higher with an array of radio
antennas. Since the amplitude of the radio signal can be measured absolutely
and increases with the shower energy, radio measurements can be used to
determine the air-shower energy on an absolute scale. We show that calibrated
measurements of radio detectors operated in coincidence with host experiments
measuring air showers based on other techniques can be used for comparing the
energy scales of these host experiments. Using two approaches, first via direct
amplitude measurements, and second via comparison of measurements with air
shower simulations, we compare the energy scales of the air-shower experiments
Tunka-133 and KASCADE-Grande, using their radio extensions, Tunka-Rex and
LOPES, respectively. Due to the consistent amplitude calibration for Tunka-Rex
and LOPES achieved by using the same reference source, this comparison reaches
an accuracy of approximately $10\,\%$ - limited by some shortcomings of LOPES,
which was a prototype experiment for the digital radio technique for air
showers. In particular we show that the energy scales of cosmic-ray
measurements by the independently calibrated experiments KASCADE-Grande and
Tunka-133 are consistent with each other on this level.


title: Charge conservation effects for high order fluctuations

abstract:
  The exact charge conservation significantly impacts multiplicity
fluctuations. The result depends strongly on the part of the system charge
carried by the particles of interest. Along with the expected suppression of
fluctuations for large systems, charge conservation may lead to negative
skewness or kurtosis for small systems.


title:
Approximating n-th differentiable functions of two variables and
  mid-point formula

abstract:
  In this work, approximations for real two variables function $f$ which has
continuous partial $(n-1)$-derivatives $(n \ge 1)$ and has the $n$--th partial
derivative of bounded bivariation or absolutely continuous are established.
Explicit bounds for this representation are given. An approximation of a
function $f$ by its mid-point formula with its error is established.


title:
On uniqueness properties of solutions of the Toda and Kac-van Moerbeke
  hierarchies

abstract:
  We prove that a solution of the Toda lattice cannot decay too fast at two
different times unless it is trivial. In fact, we establish this result for the
entire Toda and Kac-van Moerbeke hierarchies.


title: Riemann-Lagrange geometry for starfish-coral dynamical system

abstract:
  In this paper we develop the Riemann-Lagrange geometry, in the sense of
nonlinear connection, d-torsions, d-curvatures and jet Yang-Mills entity,
associated with the dynamical system concerning social interaction in colonial
organisms.


title:
Uniqueness Results for Weak Leray-Hopf Solutions of the Navier-Stokes
  System with Initial Values in Critical Spaces

abstract:
  The main subject of this paper concerns the establishment of certain classes
of initial data, which grant short time uniqueness of the associated weak
Leray-Hopf solutions of the three dimensional Navier-Stokes equations. In
particular, our main theorem that this holds for any solenodial initial data,
with finite $L_2(\mathbb{R}^3)$ norm, that also belongs to to certain subsets
of $VMO^{-1}(\mathbb{R}^3)$. As a corollary of this, we obtain the same
conclusion for any solenodial $u_{0}$ belonging to $L_{2}(\mathbb{R}^3)\cap
\mathbb{\dot{B}}^{-1+\frac{3}{p}}_{p,\infty}(\mathbb{R}^3)$, for any
$3<p<\infty$. Here,
$\mathbb{\dot{B}}^{-1+\frac{3}{p}}_{p,\infty}(\mathbb{R}^3)$ denotes the
closure of test functions in the critical Besov space
${\dot{B}}^{-1+\frac{3}{p}}_{p,\infty}(\mathbb{R}^3)$. Our results rely on the
establishment of certain continuity properties near the initial time, for weak
Leray-Hopf solutions of the Navier-Stokes equations, with these classes of
initial data. Such properties seem to be of independent interest. Consequently,
we are also able to show if a weak Leray-Hopf solution $u$ satisfies certain
extensions of the Prodi-Serrin condition on $\mathbb{R}^3 \times ]0,T[$, then
it is unique on $\mathbb{R}^3 \times ]0,T[$ amongst all other weak Leray-Hopf
solutions with the same initial value. In particular, we show this is the case
if $u\in L^{q,s}(0,T; L^{p,s}(\mathbb{R}^3))$ or if it's $L^{q,\infty}(0,T;
L^{p,\infty}(\mathbb{R}^3))$ norm is sufficiently small, where $3<p< \infty$,
$1\leq s<\infty$ and $3/p+2/q=1$.


title: Multiplayer parallel repetition for expander games

abstract:
  We investigate the value of parallel repetition of one-round games with any
number of players $k\ge 2$. It has been an open question whether an analogue of
Raz's Parallel Repetition Theorem holds for games with more than two players,
i.e., whether the value of the repeated game decays exponentially with the
number of repetitions. Verbitsky has shown, via a reduction to the density
Hales-Jewett theorem, that the value of the repeated game must approach zero,
as the number of repetitions increases. However, the rate of decay obtained in
this way is extremely slow, and it is an open question whether the true rate is
exponential as is the case for all two-player games.
  Exponential decay bounds are known for several special cases of multi-player
games, e.g., free games and anchored games. In this work, we identify a certain
expansion property of the base game and show all games with this property
satisfy an exponential decay parallel repetition bound. Free games and anchored
games satisfy this expansion property, and thus our parallel repetition theorem
reproduces all earlier exponential-decay bounds for multiplayer games. More
generally, our parallel repetition bound applies to all multiplayer games that
are connected in a certain sense.
  We also describe a very simple game, called the GHZ game, that does not
satisfy this connectivity property, and for which we do not know an exponential
decay bound. We suspect that progress on bounding the value of this the
parallel repetition of the GHZ game will lead to further progress on the
general question.


title:
From thermal to excited-state quantum phase transitions ---the Dicke
  model

abstract:
  We study the thermodynamics of the full version of the Dicke model, including
all the possible values of the total angular momentum $j$, with both
microcanonical and canonical ensembles. We focus on how the excited-state
quantum phase transition, which only appears in the microcanonical description
of the maximum angular momentum sector, $j=N/2$, change to a standard thermal
phase transition when all the sectors are taken into account. We show that both
the thermal and the excited-state quantum phase transitions have the same
origin; in other words, that both are two faces of the same phenomenon. Despite
all the logarithmic singularities which characterize the excited-state quantum
phase transition are ruled out when all the $j$-sectors are considered, the
critical energy (or temperature) still divides the spectrum in two regions: one
in which the parity symmetry can be broken, and another in which this symmetry
is always well defined.


title:
Fano lines in the reflection spectrum of directly coupled systems of
  waveguides and cavities: measurements, modeling and manipulation of the Fano
  asymmetry

abstract:
  We measure and analyze reflection spectra of directly coupled systems of
waveguides and cavities. The observed Fano lines offer insight in the
reflection and coupling processes. Very different from side-coupled systems,
the observed Fano line shape is not caused by the termini of the waveguide, but
the coupling process between the measurement device fiber and the waveguide.
Our experimental results and analytical model show that the Fano parameter that
describes the Fano line shape is very sensitive to the coupling condition. A
movement of the fiber well below the Rayleigh range can lead to a drastic
change of the Fano line shape.


title:
Superradiance of a charged scalar field coupled to the Einstein-Maxwell
  equations

abstract:
  We consider the Einstein-Maxwell-Klein-Gordon equations for a spherically
symmetric scalar field scattering off a Reissner-Nordstr\"om black hole in
asymptotically flat spacetime. The equations are solved numerically using a
hyperboloidal evolution scheme. For suitable frequencies of the initial data,
superradiance is observed, leading to a substantial decrease of mass and charge
of the black hole. We also derive a Bondi mass loss formula using the Kodama
vector field and investigate the late-time decay of the scalar field.


title:
Analogue of Pontryagin's maximum principle for multiple integrals
  minimization problems

abstract:
  The theorem like Pontryagin's maximum principle for multiple integrals is
proved. Unlike the usual maximum principle, the maximum should be taken not
over all matrices, but only on matrices of rank one. Examples are given.


title:
Dislocation Mobility and Anomalous Shear Modulus Effect in $^4$He
  Crystals

abstract:
  We calculate the dislocation glide mobility in solid $^4$He within a model
that assumes the existence of a superfluid field associated with dislocation
lines. Prompted by the results of this mobility calculation, we study within
this model the role that such a superfluid field may play in the motion of the
dislocation line when a stress is applied to the crystal. To do this, we relate
the damping of dislocation motion, calculated in the presence of the assumed
superfluid field, to the shear modulus of the crystal. As the temperature
increases, we find that a sharp drop in the shear modulus will occur at the
temperature where the superfluid field disappears. We compare the drop in shear
modulus of the crystal arising from the temperature dependence of the damping
contribution due to the superfluid field, to the experimental observation of
the same phenomena in solid $^4$He and find quantitative agreement. Our results
indicate that such a superfluid field plays an important role in dislocation
pinning in a clean solid $^4$He at low temperatures and in this regime may
provide an alternative source for the unusual elastic phenomena observed in
solid $^4$He.


title: Hypersurface-deformation algebroids and effective space-time models

abstract:
  In canonical gravity, covariance is implemented by brackets of
hypersurface-deformation generators forming a Lie algebroid. Lie algebroid
morphisms therefore allow one to relate different versions of the brackets that
correspond to the same space-time structure. An application to examples of
modified brackets found mainly in models of loop quantum gravity can in some
cases map the space-time structure back to the classical Riemannian form after
a field redefinition. For one type of quantum corrections (holonomies),
signature change appears to be a generic feature of effective space-time, and
is shown here to be a new quantum space-time phenomenon which cannot be mapped
to an equivalent classical structure. In low-curvature regimes, our
constructions prove the existence of classical space-time structures assumed
elsewhere in models of loop quantum cosmology, but also shows the existence of
additional quantum corrections that have not always been included.


title: The Standard Model Effective Field Theory and Next to Leading Order

abstract:
  We review the status of calculations in the Standard Model Effective Field
Theory (SMEFT) beyond leading order (LO). Improving the SMEFT beyond LO allows
theoretical errors to be characterized and reduced when considering SMEFT
interpretations of the data, which is essential considering the improving
experimental precision at LHC. Next to leading order results also allow a more
consistent analysis of measurements with different effective scales in the
SMEFT. Going beyond LO is clearly important in the event that deviations from
the SM are large enough that experimental indications of physics beyond the SM
emerge. We discuss a consistent and well defined approach to LO in the SMEFT,
so that the improvement to NLO is straightforward. We discuss the basic issues
involved in improving calculations to NLO in the SMEFT, and review the advances
in this direction that have been achieved to date.


title:
Gravitoelectromagnetism: Basic principles, novel approaches and their
  application to Electromagnetism

abstract:
  This work is focused on the theory of Gravitoelectromagnetism (GEM). In the
first part of this work we present a brief review of gravitoelectromagnetism,
we locate and discuss all the problems which appear in this approach. We also
try to avoid these problems by proposing new approaches in which we use the
additional degrees of freedom of the gravitational field. In the second part of
this work, we review our previous work regarding the construction of a
tensorial theory, using the formalism of General Relativity, which aims to
describe the true electromagnetism. We also extend this theory in order to make
it more realistic. Finally in the third part of this work, we investigate the
existence of gravitational invariants similar to the electromagnetic ones.


title: Tensor form factors of the octet hyperons in QCD

abstract:
  Light-cone QCD sum rules to leading order in QCD are used to investigate the
tensor form factors of the $\Sigma-\Sigma$, $\Xi-\Xi$ and $ \Sigma-\Lambda$
transitions in the range $1 GeV^2 \leq Q^2 \leq 10 GeV^2$. The DAs of $\Sigma$,
$\Xi$ and $\Lambda$ baryon have been calculated without higher order terms.
Then, study including higher order corrections have been done for $\Sigma$ and
$\Lambda$ baryon. The result of form factors are obtained using these two DAs.
We make a comparison with the predictions of the chiral quark soliton model.


title: Monopole star products are non-alternative

abstract:
  Non-associative algebras appear in some quantum-mechanical systems, for
instance if a charged particle in a distribution of magnetic monopoles is
considered. Using methods of deformation quantization it is shown here, that
algebras for such systems cannot be alternative, i.e. their associator cannot
be completely anti-symmetric.


title:
Efficiently estimating the error distribution in nonparametric
  regression with responses missing at random

abstract:
  This article considers nonparametric regression models with multivariate
covariates and with responses missing at random. We estimate the regression
function with a local polynomial smoother. The residual-based empirical
distribution function that only uses complete cases, i.e. residuals that can
actually be constructed from the data, is shown to be efficient in the sense of
H\'ajek and Le Cam. In the proofs we derive, more generally, the efficient
influence function for estimating an arbitrary linear functional of the error
distribution; this covers the distribution function as a special case. We also
show that the complete case residual-based empirical distribution function
admits a functional central limit theorem. The article concludes with a small
simulation study investigating the performance of the complete case
residual-based empirical distribution function.


title: The Henon-Heiles system defined on canonically deformed space-time

abstract:
  In this article we provide canonically deformed classical Henon-Heiles
system. Further we demonstrate that for proper value of deformation parameter
$\theta$ there appears chaos in the model.


title:
Geometric and growth rate tests of General Relativity with recovered
  linear cosmological perturbations

abstract:
  I investigate the consistency of the VIMOS Public Extragalactic Redshift
Survey v7 galaxy sample with the expansion history and linear growth rate
predicted by General Relativity (GR) and a Planck (2015) cosmology. To do so, I
measure the redshift-space power spectrum, which is anisotropic due to both
redshift-space distortions (RSD) and the Alcock-Paczynski (AP) effect. In
Chapter 6, I place constraints of $f \sigma_8(0.76) = 0.44 \pm 0.04$ and $f
\sigma_8(1.05) = 0.28 \pm 0.08$, which remain consistent with GR at 95%
confidence. Marginalising over the anisotropic AP effect degrades the
constraints by a factor of three but allows $F_{AP} \equiv (1+z) D_A H/c$ to be
simultaneously constrained. The VIPERS v7 joint-posterior on $(f \sigma_8,
F_{AP})$ shows no compelling deviation from GR.
  Chapter 7 investigates the inclusion of a simple density transform:
`clipping' prior to the RSD analysis. This tackles the root-cause of
non-linearity and may extend the validity of perturbation theory. Moreover,
this marked statistic would amplify signatures of shielded modified gravity
models and includes information not available to the power spectrum. I show
that a linear real-space power spectrum with a Kaiser factor and a Lorentzian
damping yields a significant bias without clipping, but that this may be
removed with a strict threshold; similar behaviour is observed for the data.
Estimates of $f \sigma_8$ for different thresholds are highly correlated, but
this may be obtained using mocks. A maximum likelihood estimate from a
combination of thresholds is shown to achieve a 16% decrease in statistical
error relative to a single-threshold estimate. The results are encouraging to
date but represent a work in progress; the final analysis will be submitted to
Astronomy & Astrophysics as Wilson et al. (2016).


title:
Comments on "Bayesian Solution Uncertainty Quantification for
  Differential Equations" by Chkrebtii, Campbell, Calderhead & Girolami

abstract:
  I would like to thank the authors for their interesting and very clearly
presented paper discussing probabilistic solvers for ODEs and PDEs.


title:
The geometry of rank decompositions of matrix multiplication I: 2x2
  matrices

abstract:
  This is the first in a series of papers on rank decompositions of the matrix
multiplication tensor. In this paper we: establish general facts about rank
decompositions of tensors, describe potential ways to search for new matrix
multiplication decompositions, give a geometric proof of the theorem of
Burichenko's theorem establishing the symmetry group of Strassen's algorithm,
and present two particularly nice subfamilies in the Strassen family of
decompositions.


title:
Hydrogen release at metal-oxide interfaces: A first principle study of
  hydrogenated Al/SiO$_2$ interfaces

abstract:
  The Anode Hydrogen Release (AHR) mechanism at interfaces is responsible for
the generation of defects, that traps charge carriers and can induce dielectric
breakdown in Metal-Oxide-Semiconductor Field Effect Transistors. The AHR has
been extensively studied at Si/SiO$_2$ interfaces but its characteristics at
metal-silica interfaces remain unclear. In this study, we performed Density
Functional Theory (DFT) calculations to study the hydrogen release mechanism at
the typical Al/SiO$_2$ metal-oxide interface. We found that interstitial
hydrogen atoms can break interfacial Al-Si bonds, passivating a Si $sp^3$
orbital. Interstitial hydrogen atoms can also break interfacial Al-O bonds, or
be adsorbed at the interface on aluminum, forming stable Al-H-Al bridges. We
showed that hydrogenated O-H, Si-H and Al-H bonds at the Al/SiO$_2$ interfaces
are polarized. The resulting bond dipole weakens the O-H and Si-H bonds, but
strengthens the Al-H bond under the application of a positive bias at the metal
gate. Our calculations indicate that Al-H bonds and O-H bonds are more
important than Si-H bonds for the hydrogen release process.


title:
Quantum dot attached to superconducting leads: Relation between
  symmetric and asymmetric coupling

abstract:
  We study the Anderson single-level quantum dot attached to two BCS
superconducting leads with the same gap size. We reveal that a system with
asymmetric tunnel coupling to the leads ($\Gamma_{L}\neq\Gamma_{R}$) can be
related to the symmetric system with the same net coupling strength
$\Gamma=\Gamma_{L}+\Gamma_{R}$. Surprisingly, it is the symmetric case which is
the most general, meaning that all physical quantities in case of asymmetric
coupling are fully determined by the symmetric ones. We give ready-to-use
conversion formulas for the $0-\pi$ phase transition boundary, on-dot
quantities, and the Josephson current, and illustrate them on the NRG results
of Oguri, Tanaka and Bauer [Phys. Rev. B 87, 075432 (2013)] for the
three-terminal setup. We apply our theory to the recent $0-\pi$ transition
measurement of Delagrange et al. [Phys. Rev. B 93, 196437 (2016)] and determine
the asymmetry of the experimental setup from the measured transition width.
Finally, we establish that the widely assumed Kondo "universality" of physical
quantities depending only on the ratio of the Kondo temperature and the
superconducting gap $T_{K}/\Delta$ cannot hold for asymmetric junctions.


title:
Nonparametric Dynamic State Space Modeling of Observed Circular Time
  Series with Circular Latent States: A Bayesian Perspective

abstract:
  Circular time series has received relatively little attention in statistics
and modeling complex circular time series using the state space approach is
non-existent in the literature. In this article we introduce a flexible
Bayesian nonparametric approach to state space modeling of observed circular
time series where even the latent states are circular random variables.
Crucially, we assume that the forms of both observational and evolutionary
functions, both of which are circular in nature, are unknown and time-varying.
We model these unknown circular functions by appropriate wrapped Gaussian
processes having desirable properties.
  We develop an effective Markov chain Monte Carlo strategy for implementing
our Bayesian model, by judiciously combining Gibbs sampling and
Metropolis-Hastings methods. Validation of our ideas with a simulation study
and two real bivariate circular time series data sets, where we assume one of
the variables to be unobserved, revealed very encouraging performance of our
model and methods.
  We finally analyse a data consisting of directions of whale migration,
considering the unobserved ocean current direction as the latent circular
process of interest. The results that we obtain are encouraging, and the
posterior predictive distribution of the observed process correctly predicts
the observed whale movement.


title: Cosmological aspects of a unified dark energy and dust dark matter model

abstract:
  Recently, a model of modified gravity plus single scalar field model was
proposed, in which the scalar couples both to the standard Riemannian volume
form given by the square root of the determinant of the Riemannian metric, as
well as to another non-Riemannian volume form given in terms of an auxiliary
maximal rank antisymmetric tensor gauge field. This model provides an exact
unified description of both dark energy (via dynamically generated cosmological
constant) and dark matter (as a "dust" fluid due to a hidden nonlinear Noether
symmetry).
  In this paper we test the model against Supernovae type Ia experimental data
and investigate the future Universe evolution which follows from it. Our
results show that this model has very interesting features allowing various
scenarios of Universe evolution and in the same time perfectly fits
contemporary observational data. It can describe exponentially expanding or
finite expanding Universe and moreover, a Universe with phase transition of
first kind. The phase transition occurs to a new, emerging at some time ground
state with lower energy density, which affects significantly the Universe
evolution.


title:
Curbing cyber-crime and Enhancing e-commerce security with Digital
  Forensics

abstract:
  The explosion in the e-commerce industry which has been necessitated by the
growth and advance expansion of Information technology and its related
facilities in recent years have been met with adverse security issues
consequently affecting the industry and the entire online activities. This
paper exams the prevailing security threats e-commerce is facing which is
predominantly known as cyber-crime and how computer related technology and
facilities such as digital forensics tools can be adopted extensively to ensure
security in online related business activities. This paper investigated the
risk, damage and the cost cyber-crime poses to individuals and organizations
when they become victims. As it is obvious transacting business online as well
as all related online activities has become inherent in our everyday life. The
paper also comprehensively elucidate on some of the cyber-crime activities that
are posing serious threat to the security of E-commerce. Amazon and eBay were
used as the case of study in relation to respondents who patronizes these
renowned e-commerce sites for various transactions.
  Keywords: E-commerce Security,Cyber-Crime,digital forensics, Network
forensics, Network security, Online transactions, Identity theft, hacking.


title: Flow polytopes and the space of diagonal harmonics

abstract:
  A result of Haglund implies that the $(q,t)$-bigraded Hilbert series of the
space of diagonal harmonics is a $(q,t)$-Ehrhart function of the flow polytope
of a complete graph with netflow vector $(-n, 1, \dots, 1)$. We study the
$(q,t)$-Ehrhart functions of flow polytopes of threshold graphs with arbitrary
netflow vectors. Our results generalize previously known specializations of the
mentioned bigraded Hilbert series at $t=1$, $0$, and $q^{-1}$. As a corollary
to our results, we obtain a proof of a conjecture of Armstrong, Garsia,
Haglund, Rhoades and Sagan about the $(q, q^{-1})$-Ehrhart function of the flow
polytope of a complete graph with an arbitrary netflow vector.


title:
Atomic bonding and electrical potential at metal/oxide interfaces, a
  first principle study

abstract:
  A number of electronic devices involve metal/oxide interfaces in their
structure where the oxide layer plays the role of electrical insulator. As the
downscaling of devices continues, the oxide thickness can spread over only a
few atomic layers, making the role of interfaces prominent on its insulating
properties. The prototypical Al/SiO2 metal/oxide interface is investigated
using first principle calculations, and the effect of the interfacial atomic
bonding is evidenced. It is shown that the interface bonding configuration
critically dictates the mechanical and electronic properties of the interface.
Oxygen atoms are found to better delimit the oxide boundaries than cations.
Interfacial cation-metal bonds allow the metal potential to leak inside the
oxide layer, without atomic diffusion, leading to a virtual oxide thinning.


title: On the Behaviour of Deviant Communities in Online Social Networks

abstract:
  On-line social networks are complex ensembles of inter-linked communities
that interact on different topics. Some communities are characterized by what
are usually referred to as deviant behaviors, conducts that are commonly
considered inappropriate with respect to the society's norms or moral
standards. Eating disorders, drug use, and adult content consumption are just a
few examples. We refer to such communities as deviant networks. It is commonly
believed that such deviant networks are niche, isolated social groups, whose
activity is well separated from the mainstream social-media life. According to
this assumption, research studies have mostly considered them in isolation. In
this work we focused on adult content consumption networks, which are present
in many on-line social media and in the Web in general. We found that few small
and densely connected communities are responsible for most of the content
production. Differently from previous work, we studied how such communities
interact with the whole social network. We found that the produced content
flows to the rest of the network mostly directly or through bridge-communities,
reaching at least 450 times more users. We also show that a large fraction of
the users can be inadvertently exposed to such content through indirect content
resharing. We also discuss a demographic analysis of the producers and
consumers networks. Finally, we show that it is easily possible to identify a
few core users to radically uproot the diffusion process. We aim at setting the
basis to study deviant communities in context.


title: Oh-RAM! One and a Half Round Atomic Memory

abstract:
  Emulating atomic read/write shared objects in a message-passing system is a
fundamental problem in distributed computing. Considering that network
communication is the most expensive resource, efficiency is measured first of
all in terms of the communication needed to implement read and write
operations. It is well known that 2 communication round-trip phases involving
in total 4 message exchanges are sufficient to implemented atomic operations.
It is also known that under certain constraints on the number of readers with
respect to the numbers of replica servers and failures it is possible to
implement single-writer atomic objects such that each operation involves one
round-trip phase. We present algorithms that allow operations to complete in 3
communication exchanges without imposing any constraints on the number of
readers and writers. Specifically, we present an atomic memory implementation
for the SWMR setting, where reads complete in 3 communication exchanges and
writes complete in 2 exchanges. We pose the question of whether it is possible
to implement MWMR memory where operations complete in at most 3 communication
exchanges. We answer this question in the negative by showing that an atomic
memory implementation is impossible if both read and write operations take 3
communication exchanges, even when assuming two writers, two readers, and a
single replica server failure. Motivated by this impossibility result, we
provide a MWMR atomic memory implementation where reads involve 3 and writes 4
communication exchanges. In light of our impossibility result these algorithms
are optimal in terms of the number of communication exchanges. We rigorously
reason about the correctness of the algorithms.


title: Nonwoven scaffolds for bone regeneration

abstract:
  Developing successful scaffolds requires clinicians to adopt a
multidisciplinary approach in order to understand and stimulate the natural
bone regeneration process. A variety of natural and synthetic biomaterials,
including naturally extracted, chemically functionalised collagen and synthetic
Poly(epsilon-caprolactone) (PCL), can be manufactured into fibres, enabling the
formation of nonwoven scaffolds. Many different nonwoven architectures and
structural features can then be introduced, depending on the manufacturing
parameters. This chapter introduces methods for producing scaffolds with
appropriate pore sizes by means of electrospinning, and it outlines the
opportunities that exist for other nonwoven manufacturing technologies in the
development of biomimetic products.


title: Content Selection in Data-to-Text Systems: A Survey

abstract:
  Data-to-text systems are powerful in generating reports from data
automatically and thus they simplify the presentation of complex data. Rather
than presenting data using visualisation techniques, data-to-text systems use
natural (human) language, which is the most common way for human-human
communication. In addition, data-to-text systems can adapt their output content
to users' preferences, background or interests and therefore they can be
pleasant for users to interact with. Content selection is an important part of
every data-to-text system, because it is the module that determines which from
the available information should be conveyed to the user. This survey initially
introduces the field of data-to-text generation, describes the general
data-to-text system architecture and then it reviews the state-of-the-art
content selection methods. Finally, it provides recommendations for choosing an
approach and discusses opportunities for future research.


title:
Quasi-polynomiality of monotone orbifold Hurwitz numbers and
  Grothendieck's dessins d'enfants

abstract:
  We prove quasi-polynomiality for monotone and strictly monotone orbifold
Hurwitz numbers. The second enumerative problem is also known as enumeration of
a special kind of Grothendieck's dessins d'enfants or $r$-hypermaps. These
statements answer positively two conjectures proposed by Do-Karev and
Do-Manescu. We also apply the same method to the usual orbifold Hurwitz numbers
and obtain a new proof of the quasi-polynomiality in this case.
  In the second part of the paper we show that the property of
quasi-polynomiality is equivalent in all these three cases to the property that
the $n$-point generating function has a natural representation on the $n$-th
cartesian powers of a certain algebraic curve. These representations are the
necessary conditions for the Chekhov-Eynard-Orantin topological recursion.


title:
On the equation $x + y = 1$ in finitely generated groups in positive
  characteristic

abstract:
  Let $K$ be a field of characteristic $p > 0$ and let $G$ be a subgroup of
$K^\ast \times K^\ast$ with $\text{dim}_\mathbb{Q}(G \otimes_\mathbb{Z}
\mathbb{Q}) = r$ finite. Then Voloch proved that the equation $ax + by = 1
\text{ in } (x, y) \in G$ for given $a, b \in K^\ast$ has at most $p^r(p^r + p
- 2)/(p - 1)$ solutions $(x, y) \in G$, unless $(a, b)^n \in G$ for some $n
\geq 1$.
  Voloch also conjectured that this upper bound can be replaced by one
depending only on $r$. Our main theorem answers this conjecture positively. We
prove that there are at most $31 \cdot 19^{r + 1}$ solutions $(x, y)$ unless
$(a, b)^n \in G$ for some $n \geq 1$ with $(n, p) = 1$.
  During the proof of our main theorem we generalize the work of Beukers and
Schlickewei to positive characteristic, which heavily relies on diophantine
approximation methods. This is a surprising feat on its own, since usually
these methods can not be transferred to positive characteristic.


title:
Sub-MeV Bosonic Dark Matter, Misalignment Mechanism and Galactic Dark
  Matter Halo Luminosities

abstract:
  We explore a scenario that the dark matter is a boson condensate created by
the misalignment mechanism, in which a spin 0 boson (an axion-like particle)
and a spin 1 boson (the dark photon) are considered, respectively. We find that
although the sub-MeV dark matter boson is extremely stable, the huge number of
dark matter particles in a galaxy halo makes the decaying signal detectable. A
galaxy halo is a large structure bounded by gravity with a typical
$\sim10^{12}$ solar mass, and the majority of its components are made of dark
matter. For the axion-like particle case, it decays via $\phi\to \gamma\gamma$,
therefore the photon spectrum is monochromatic. For the dark photon case, it is
a three body decay $A'\to\gamma\gamma\gamma$. However, we find that the photon
spectrum is heavily peaked at $M/2$ and thus can facilitate observation. We
also suggest a physical explanation for the three body decay spectrum by
comparing the physics in the decay of orthopositronium. In addition, for both
cases, the decaying photon flux can be measured for some regions of parameter
space using current technologies.

categories: hep-ph astro-ph.CO astro-ph.GA astro-ph.HE hep-th


title:
Decomposition of Multi-Agent Planning under Distributed Motion and Task
  LTL Specifications

abstract:
  The aim of this work is to introduce an efficient procedure for discrete
multi-agent planning under local complex temporal logic behavior
specifications. While the first part of an agent's behavior specification
constraints the agent's trace and is independent, the second part of the
specification expresses the agent's tasks in terms of the services to be
provided along the trace and may impose requests for the other agents'
collaborations. To fight the extreme computational complexity of centralized
multi-agent planning, we propose a two-phase automata-based solution, where we
systematically decouple the planning procedure for the two types of
specifications. At first, we only consider the former specifications in a fully
decentralized way and we compactly represent each agents' admissible traces by
abstracting away the states that are insignificant for the satisfaction of
their latter specifications. Second, the synchronized planning procedure uses
only the compact representations. The satisfaction of the overall specification
is guaranteed by construction for each agent. An illustrative example
demonstrating the practical benefits of the solution is included.


title:
Multi-Agent Planning under Local LTL Specifications and Event-Based
  Synchronization

abstract:
  We study the problem of plan synthesis for multi-agent systems, to achieve
complex, high-level, long-term goals that are assigned to each agent
individually. As the agents might not be capable of satisfying their respective
goals by themselves, requests for other agents' collaborations are a part of
the task descriptions. We consider that each agent is modeled as a discrete
state-transition system and its task specification takes a form of a linear
temporal logic formula, which may contain requirements and constraints on the
other agent's behavior. A traditional automata-based approach to multi-agent
plan synthesis from such specifications builds on centralized team planning and
full team synchronization after each agents' discrete step, and thus suffers
from extreme computational demands. We aim at reducing the computational
complexity by decomposing the plan synthesis problem into finite horizon
planning problems that are solved iteratively, upon the run of the agents. As
opposed to full synchronization, we introduce an event-based synchronization
that allows our approach to efficiently adapt to different time durations of
different agents' discrete steps. We discuss the correctness of the solution
and find assumptions, under which the proposed iterative algorithm leads to
provable eventual satisfaction of the desired specifications.


title: Testing dust trapping in the circumbinary disk around GG Tau A

abstract:
  The protoplanetary disk around the GGTau A binary system is so far one of the
most studied young circumbinary disk. Observations of the dust continuum
emission at sub-mm/mm wavelengths detected a dust ring located between 200AU
and 300AU from the center of mass of the system. If the disk and the binary
orbit are coplanar, given the observed projected separation of the stars in the
binary system, the classical theory of tidal interaction between a binary
system and its circumbinary disk predicts a truncation radius which is
significantly smaller than the measured inner radius of the mm-sized dust ring.
We investigate the origin of this dust ring structure in the GG Tau A disk,
test whether the interaction between the binary and the disk can produce a dust
trap at the location of the observed ring, and discuss an alternative scenario
which invokes a misalignment between the disk and the stellar orbital planes.
We run a set of hydrodynamical simulations for an orbit consistent with the
astrometric solutions for the GG Tau A stellar proper motions, and for
different disk temperature and viscosities. We then apply a dust evolution
model in post-processing in order to to retrieve the distribution of mm-sized
grains. Comparing models and observations, we show that, if the binary orbit
and the disk were coplanar,the tidal truncation of the circumbinary disk would
occur at a radius that is too small compared to the inner edge inferred by the
dust observations, and that the pressure bump and the dust ring in the models
would be located at <150AU from the center of mass of the stellar system. This
shows that the GG Tau A disk cannot be coplanar with the binary orbital plane.
We also discuss the viability of the misaligned disk scenario, suggesting that
in order for dust trapping to occur at the observed radius, the disk and
orbital plane must be misaligned by an angle of about 25 degrees.


title: Tracing the gravitational potential using cosmic voids

abstract:
  The properties of large underdensities in the distribution of galaxies in the
Universe, known as cosmic voids, are potentially sensitive probes of
fundamental physics. We use data from the MultiDark suite of N-body simulations
and multiple halo occupation distribution mocks to study the relationship
between galaxy voids, identified using a watershed void-finding algorithm, and
the gravitational potential $\Phi$. We find that the majority of galaxy voids
correspond to local density minima in larger-scale overdensities, and thus lie
in potential wells. However, a subset of voids can be identified that closely
trace maxima of the gravitational potential and thus stationary points of the
velocity field. We identify a new void observable, $\lambda_v$, which depends
on a combination of the void size and the average galaxy density contrast
within the void, and show that it provides a good proxy indicator of the
potential at the void location. A simple linear scaling of $\Phi$ as a function
of $\lambda_v$ is found to hold, independent of the redshift and properties of
the galaxies used as tracers of voids. We provide an accurate fitting formula
to describe the spherically averaged potential profile $\Phi(r)$ about void
centre locations. We discuss the importance of these results for the
understanding of the evolution history of voids, and for their use in precision
measurements of the integrated Sachs-Wolfe effect, gravitational lensing and
peculiar velocity distortions in redshift space.


title:
Resonant inelastic X-ray scattering study of spin-wave excitations in
  the cuprate parent compound Ca$_{2}$CuO$_2$Cl$_2$

abstract:
  By means of resonant inelastic x-ray scattering at the Cu L$_3$ edge, we
measured the spin wave dispersion along $\langle$100$\rangle$ and
$\langle$110$\rangle$ in the undoped cuprate Ca$_2$CuO$_2$Cl$_2$. The data
yields a reliable estimate of the superexchange parameter $J$ = 135 $\pm$ 4 meV
using a classical spin-1/2 2D Heisenberg model with nearest-neighbor
interactions and including quantum fluctuations. Including further exchange
interactions increases the estimate to $J$ = 141 meV. The 40 meV dispersion
between the magnetic Brillouin zone boundary points (1/2,\,0) and (1/4,\,1/4)
indicates that next-nearest neighbor interactions in this compound are
intermediate between the values found in La$_{2}$CuO$_4$ and
Sr$_2$CuO$_2$Cl$_2$. Owing to the low-$Z$ elements composing
Ca$_2$CuO$_2$Cl$_2$, the present results may enable a reliable comparison with
the predictions of quantum many-body calculations, which would improve our
understanding of the role of magnetic excitations and of electronic
correlations in cuprates.


title: Existence and stability of viscous vortices

abstract:
  Vorticity plays a prominent role in the dynamics of incompressible viscous
flows. In two-dimensional freely decaying turbulence, after a short transient
period, evolution is essentially driven by interactions of viscous vortices,
the archetype of which is the self-similar Lamb-Oseen vortex. In three
dimensions, amplification of vorticity due to stretching can counterbalance
viscous dissipation and produce stable tubular vortices. This phenomenon is
illustrated in a famous model originally proposed by Burgers, where a straight
vortex tube is produced by a linear uniaxial strain field. In real flows vortex
lines are usually not straight, and can even form closed curves, as in the case
of axisymmetric vortex rings which are very common in nature and in laboratory
experiments. The aim of this chapter is to review a few rigorous results
concerning existence and stability of viscous vortices in simple geometries.


title: On a new non-Boussinesq instability in stratified lakes and oceans

abstract:
  Lakes and many other geophysical flows are shallow, density stratified, and
contain a free-surface. Conventional studies on stratified shear instabilities
make Boussinesq approximation. Free-surface arising due to large density
variations between air and water cannot be taken into consideration under this
approximation. Hence the free-surface is usually replaced by a rigid-lid, and
therefore has little effect on the stability of the fluid below it. In this
paper we have performed non-Boussinesq linear stability analyses of a double
circulation velocity profile prevalent in two-layered density stratified lakes.
One of our analyses is performed by considering the presence of wind, while the
other one considers quiescent air. Both analyses have shown similar growth
rates and stability boundaries. We have compared our non-Boussinesq study with
a corresponding Boussinesq one. The maximum non-Boussinesq growth rate is found
to be an order of magnitude greater than the maximum Boussinesq growth rate.
Furthermore, the stability curves in these two studies are very different. The
non-Boussinesq instability as well as the Boussinseq one can become three
dimensional in some sub-ranges of the bulk Richardson number. An analytical
study has also been conducted on a simple broken-line profile representing
double circulation in order to complement the numerical stability analysis. The
analytical growth rates are in good agreement with the non-Boussinesq numerical
growth rates observed in continuous profiles. The physical mechanism behind
this non-Boussinesq instability is the resonant interaction between a surface
vorticity-gravity wave existing at the free-surface (air-water interface), and
an interfacial vorticity-gravity wave existing at the pycnocline (warm and cold
water interface). We expect similar kind of non-Boussinesq instability to occur
in the upper layer of oceans.


title: On the estimation of extreme directional multivariate quantiles

abstract:
  In multivariate extreme value theory (MEVT), the focus is on analysis outside
of the observable sampling zone, which implies that the region of interest is
associated to high risk levels. This work provides tools to include directional
notions into the MEVT, giving the opportunity to characterize the recently
introduced directional multivariate quantiles (DMQ) at high levels. Then, an
out-sample estimation method for these quantiles is given. A bootstrap
procedure carries out the estimation of the tuning parameter in this
multivariate framework and helps with the estimation of the DMQ. Asymptotic
normality for the proposed estimator is provided and the methodology is
illustrated with simulated data-sets. Finally, a real-life application to a
financial case is also performed.


title: A note on triangulated monads and categories of module spectra

abstract:
  Consider a monad on an idempotent complete triangulated category with the
property that its Eilenberg-Moore category of modules inherits a triangulation.
We show that any other triangulated adjunction realizing this monad is
'essentially monadic', i.e. becomes monadic after performing the two evident
necessary operations of taking the Verdier quotient by the kernel of the right
adjoint and idempotent completion. In this sense, the monad itself is
'intrinsically monadic'. It follows that for any highly structured ring
spectrum, its category of homotopy (a.k.a. naive) modules is triangulated if
and only if it is equivalent to its category of highly structured (a.k.a.
strict) modules.


title:
Exact solution to integrable open multi-species SSEP and macroscopic
  fluctuation theory

abstract:
  We introduce a multi-species generalization of the symmetric simple exclusion
process with open boundaries. This model possesses the property of being
integrable and appears as physically relevant because the boundary conditions
can be interpreted as the interaction with particles reservoirs with fixed
densities of each species. The system is driven out-of-equilibrium by these
reservoirs. The steady state is analytically computed in a matrix product form.
This algebraic structure allows us to obtain exact expressions for the mean
particle currents and for the one and two-point correlation functions. An
additivity principle is also derived from the matrix ansatz and permits the
computation of the large deviation functional of the density profile. We also
propose a description of the model in the context of the macroscopic
fluctuation theory and we check the consistency with the exact computations
from the finite size lattice.


title: Stability results for graphs with a critical edge

abstract:
  The classical stability theorem of Erd\H{o}s and Simonovits states that, for
any fixed graph with chromatic number $k+1 \ge 3$, the following holds: every
$n$-vertex graph that is $H$-free and has within $o(n^2)$ of the maximal
possible number of edges can be made into the $k$-partite Tur\'{a}n graph by
adding and deleting $o(n^2)$ edges. In this paper, we prove sharper
quantitative results for graphs $H$ with a critical edge, both for the
Erd\H{o}s-Simonovits Theorem (distance to the Tur\'{a}n graph) and for the
closely related question of how close an $H$-free graph is to being
$k$-partite. In many cases, these results are optimal to within a constant
factor.


title:
Non-integrated defect relation for meromorphic maps from a K\"{a}hler
  manifold intersecting hypersurfaces in subgeneral of $\mathbb P^n(\mathbb C)$

abstract:
  In this article, we establish a truncated non-integrated defect relation for
meromorphic mappings from an $m$-dimensional complete K\"{a}hler manifold into
$\mathbb P^n(\mathbb C)$ intersecting $q$ hypersurfaces $Q_1,...,Q_q$ in
$k$-subgeneral position of degree $d_i$, i.e., the intersection of any $k+1$
hypersurfaces is emptyset. We will prove that $$
\sum_{i=1}^q\delta_f^{[u-1]}(Q_i)\le (k-n+1)(n+1)+\epsilon+\frac{\rho
u(u-1)}{d}, $$ where $u$ is explicitly estimated and $d$ is the least common
multiple of $d_i'$s. Our result generalizes and improves previous results. In
the last part of this paper we will apply this result to study the distribution
of the Gauss map of minimal surfaces.


title:
Schmidt's subspace theorem for moving hypersurface in subgeneral
  position

abstract:
  In this paper, we establish a Schmidt's subspace theorem for moving
hypersurfaces in weakly subgeneral position. Our result generalizes the
previous results on Schmidt's theorem for the case of moving hypersurfaces.


title:
The compactness locus of a geometric functor and the formal construction
  of the Adams isomorphism

abstract:
  We introduce the compactness locus of a geometric functor between
rigidly-compactly generated tensor-triangulated categories, and describe it for
several examples arising in equivariant homotopy theory and algebraic geometry.
It is a subset of the tensor-triangular spectrum of the target category which,
crudely speaking, measures the failure of the functor to satisfy
Grothendieck-Neeman duality (or equivalently, to admit a left adjoint). We
prove that any geometric functor --- even one which does not admit a left
adjoint --- gives rise to a Wirthm\"uller isomorphism once one passes to a
colocalization of the target category determined by the compactness locus. When
applied to the inflation functor in equivariant stable homotopy theory, this
produces the Adams isomorphism.


title: Perfect Isometry Groups for Cyclic Groups of Prime Order

abstract:
  A perfect isometry is an important relation between blocks of finite groups
as many information about blocks are preserved by it. If we consider the group
of all perfect isometries between a block to itself then this gives another
information about the block that is also preserved by a perfect isometry. The
structure of this group depends on the block and can be fairly simple or
extremely complicated. In this paper we study the perfect isometry group for
the block of $C_p$, the cyclic group of prime order, and completely describe
the structure of this group. The result shows that any self perfect isometry
for $C_p$ is essentially either induced by an element in $\mbox{Aut}(C_p)$, or
obtained by multiplication by one of its linear characters, or a composition of
both.


title:
A general second order complete active space self-consistent-field
  solver for large-scale systems

abstract:
  We present a new second order complete active space self-consistent field
implementation to converge wavefunctions for both large active spaces and large
atomic orbital (AO) bases. Our algorithm decouples the active space
wavefunction solver from the orbital optimization in the microiterations, and
thus may be easily combined with various modern active space solvers. We also
introduce efficient approximate orbital gradient and Hessian updates, and step
size determination. We demonstrate its capabilities by calculating the
low-lying states of the Fe(\Roman{2})-porphine complex with modest resources
using a density matrix renormalization group solver in a CAS(22,27) active
space and a 3000 AO basis.


title: Self-consistent solution of Hedin's equations: semiconductors/insulators

abstract:
  The band gaps of a few selected semiconductors/insulators are obtained from
the self-consistent solution of the Hedin's equations. Two different schemes to
include the vertex corrections are studied: (i) the vertex function of the
first-order (in the screened interaction $W$) is applied in both the
polarizability $P$ and the self-energy $\Sigma$, and (ii) the vertex function
obtained from the Bethe-Salpeter equation is used in $P$ whereas the vertex of
the first-order is used in $\Sigma$. Both schemes show considerable improvement
in the accuracy of the calculated band gaps as compared to the self-consistent
$GW$ approach (sc$GW$) and to the self-consistent quasi-particle $GW$ approach
(QS$GW$). To further distinguish between the performances of two
vertex-corrected schemes one has to properly take into account the effect of
the electron-phonon interaction on the calculated band gaps which appears to be
of the same magnitude as the difference between schemes i) and ii).


title:
Structural and magnetic properties of two branches of the Tripod Kagome
  Lattice family A$_{2}$RE$_{3}$Sb$_{3}$O$_{14}$ (A = Mg, Zn; RE = Pr, Nd, Gd,
  Tb, Dy, Ho, Er, Yb)

abstract:
  We present a systematic study of the structural and magnetic properties of
two branches of the rare earth Tripod Kagome Lattice (TKL) family
A$_{2}$RE$_{3}$Sb$_{3}$O$_{14}$ (A = Mg, Zn; RE = Pr, Nd, Gd, Tb, Dy, Ho, Er,
Yb; here, we use abbreviation \textit{A-RE}, as in \textit{MgPr} for
Mg$_{2}$Pr$_{3}$Sb$_{3}$O$_{14}$), which complements our previously reported
work on \textit{MgDy}, \textit{MgGd}, and \textit{MgEr} \cite{TKL}. The present
susceptibility ($\chi_{dc}$, $\chi_{ac}$) and specific heat measurements reveal
various magnetic ground states, including the non-magnetic singlet state for
\textit{MgPr}, \textit{ZnPr}; long range orderings (LROs) for \textit{MgGd},
\textit{ZnGd}, \textit{MgNd}, \textit{ZnNd}, and \textit{MgYb}; a long range
magnetic charge ordered state for \textit{MgDy}, \textit{ZnDy}, and potentially
for \textit{MgHo}; possible spin glass states for \textit{ZnEr}, \textit{ZnHo};
the absence of spin ordering down to 80 mK for \textit{MgEr}, \textit{MgTb},
\textit{ZnTb}, and \textit{ZnYb} compounds. The ground states observed here
bear both similarities as well as striking differences from the states found in
the parent pyrochlore systems. In particular, while the TKLs display a greater
tendency towards LRO, the lack of LRO in \textit{MgHo}, \textit{MgTb} and
\textit{ZnTb} can be viewed from the standpoint of a balance among spin-spin
interactions, anisotropies and non-Kramers nature of single ion state. While
substituting Zn for Mg changes the chemical pressure, and subtly modifies the
interaction energies for compounds with larger RE ions, this substitution
introduces structural disorder and modifies the ground states for compounds
with smaller RE ions (Ho, Er, Yb).


title:
On the maximal cut of Feynman integrals and the solution of their
  differential equations

abstract:
  The standard procedure for computing scalar multi-loop Feynman integrals
consists in reducing them to a basis of so-called master integrals, derive
differential equations in the external invariants satisfied by the latter and,
finally, try to solve them as a Laurent series in $\epsilon = (4-d)/2$, where
$d$ are the space-time dimensions. The differential equations are, in general,
coupled and can be solved using Euler's variation of constants, provided that a
set of homogeneous solutions is known. Given an arbitrary differential equation
of order higher than one, there exist no general method for finding its
homogeneous solutions. In this paper we show that the maximal cut of the
integrals under consideration provides one set of homogeneous solutions,
simplifying substantially the solution of the differential equations.


title:
Geometric Langlands correspondence for SL(2), PGL(2) over the pair of
  pants

abstract:
  We establish the Geometric Langlands correspondence for rank one groups over
the projective line with three points of tame ramification.


title:
Comparison of ultracold neutron sources for fundamental physics
  measurements

abstract:
  Ultracold neutrons (UCNs) are key for precision studies of fundamental
parameters of the neutron and in searches for new CP violating processes or
exotic interactions beyond the Standard Model of particle physics. The most
prominent example is the search for a permanent electric dipole moment of the
neutron (nEDM). We have performed an experimental comparison of the leading UCN
sources currently operating. We have used a 'standard' UCN storage bottle with
a volume of 32 liters, comparable in size to nEDM experiments, which allows us
to compare the UCN density available at a given beam port.


title:
Video Analysis of "YouTube Funnies" to Aid the Study of Human Gait and
  Falls - Preliminary Results and Proof of Concept

abstract:
  Because falls are funny, YouTube and other video sharing sites contain a
large repository of real-life falls. We propose extracting gait and balance
information from these videos to help us better understand some of the factors
that contribute to falls. Proof-of-concept is explored in a single video
containing multiple (n=14) falls/non-falls in the presence of an unexpected
obstacle. The analysis explores: computing spatiotemporal parameters of gait in
a video captured from an arbitrary viewpoint; the relationship between
parameters of gait from the last few steps before the obstacle and falling vs.
not falling; and the predictive capacity of a multivariate model in predicting
a fall in the presence of an unexpected obstacle. Homography transformations
correct the perspective projection distortion and allow for the consistent
tracking of gait parameters as an individual walks in an arbitrary direction in
the scene. A synthetic top view allows for computing the average stride length
and a synthetic side view allows for measuring up and down motions of the head.
In leave-one-out cross-validation, we were able to correctly predict whether a
person would fall or not in 11 out of the 14 cases (78.6%), just by looking at
the average stride length and the range of vertical head motion during the 1-4
most recent steps prior to reaching the obstacle.


title: Universal adversarial perturbations

abstract:
  Given a state-of-the-art deep neural network classifier, we show the
existence of a universal (image-agnostic) and very small perturbation vector
that causes natural images to be misclassified with high probability. We
propose a systematic algorithm for computing universal perturbations, and show
that state-of-the-art deep neural networks are highly vulnerable to such
perturbations, albeit being quasi-imperceptible to the human eye. We further
empirically analyze these universal perturbations and show, in particular, that
they generalize very well across neural networks. The surprising existence of
universal perturbations reveals important geometric correlations among the
high-dimensional decision boundary of classifiers. It further outlines
potential security breaches with the existence of single directions in the
input space that adversaries can possibly exploit to break a classifier on most
natural images.


title:
Time-resolved measurements of surface spin-wave pulses at millikelvin
  temperatures

abstract:
  In this work, we experimentally investigate the propagation of pulsed
magnetostatic surface spin-wave (magnon) signals in an yttrium iron garnet
(YIG) waveguide at millikelvin temperatures. Our measurements are performed in
a dilution refrigerator at microwave frequencies. The excellent signal-to-noise
ratio afforded by the low-temperature environment allows the propagation of the
pulses to be observed in detail. The work gives insight both into
low-temperature magnon dynamics in YIG and the potential application of systems
of propagating magnons to solid-state quantum information processing.


title: Local contributions to Donaldson-Thomas invariants

abstract:
  Let $C$ be a smooth curve embedded in a smooth quasi-projective threefold
$Y$, and let $Q^n_C=\textrm{Quot}_n(\mathscr I_C)$ be the Quot scheme of length
$n$ quotients of its ideal sheaf. We show the identity
$\tilde\chi(Q^n_C)=(-1)^n\chi(Q^n_C)$, where $\tilde\chi$ is the Behrend
weighted Euler characteristic. When $Y$ is a projective Calabi-Yau threefold,
this shows that the DT contribution of a smooth rigid curve is the signed Euler
characteristic of the moduli space. This can be rephrased as a DT/PT
wall-crossing type formula, which can be formulated for arbitrary smooth
curves. In general, the formula is shown to be equivalent to a certain Behrend
function identity.


title: Geometric filling curves on surfaces

abstract:
  This note is about a type of quantitative density of closed geodesics on
closed hyperbolic surfaces. The main results are upper bounds on the length of
the shortest closed geodesic that $\varepsilon$-fills the surface.