title:
Biaxial-stress-driven full spin polarization in ferromagnetic hexagonal
  chromium telluride

abstract:
  It is important to spintronics to achieve fully-spin-polarized magnetic
materials that are stable and can be easily fabricated. Here, through
systematical density-functional-theory investigations, we achieve high and even
full spin polarization for carriers in the ground-state phase of CrTe by
applying tensile biaxial stress. The resulting strain is tensile in the xy
plane and compressive in the z axis. With the in-plane tensile strain
increasing, the ferromagnetic order is stable against antiferromagnetic
fluctuations, and a half-metallic ferromagnetism is achieved at an in-plane
strain of 4.8%. With the spin-orbit coupling taken into account, the spin
polarization is equivalent to 97% at the electronic phase transition point, and
then becomes 100.0% at the in-plane strain of 6.0%. These make us believe that
the full-spin-polarized ferromagnetism in this stable and easily-realizable
hexagonal phase could be realized soon, and applied in spintronics.


title:
Complexity Results for Manipulation, Bribery and Control of the Kemeny
  Procedure in Judgment Aggregation

abstract:
  We study the computational complexity of several scenarios of strategic
behavior for the Kemeny procedure in the setting of judgment aggregation. In
particular, we investigate (1) manipulation, where an individual aims to
achieve a better group outcome by reporting an insincere individual opinion,
(2) bribery, where an external agent aims to achieve an outcome with certain
properties by bribing a number of individuals, and (3) control (by adding or
deleting issues), where an external agent aims to achieve an outcome with
certain properties by influencing the set of issues in the judgment aggregation
situation. We show that determining whether these types of strategic behavior
are possible (and if so, computing a policy for successful strategic behavior)
is complete for the second level of the Polynomial Hierarchy. That is, we show
that these problems are $\Sigma^p_2$-complete.


title: Prospects for detecting ultra-high-energy particles with FAST

abstract:
  The origin of the highest-energy particles in nature, the ultra-high-energy
(UHE) cosmic rays, is still unknown. In order to resolve this mystery, very
large detectors are required to probe the low flux of these particles - or to
detect the as-yet unobserved flux of UHE neutrinos predicted from their
interactions. The `lunar Askaryan technique' is a method to do both. When
energetic particles interact in a dense medium, the Askaryan effect produces
intense coherent pulses of radiation in the MHz--GHz range. By using radio
telescopes to observe the Moon and look for nanosecond pulses, the entire
visible lunar surface ($20$ million km$^2$) can be used as an UHE particle
detector. A large effective area over a broad bandwidth is the primary
telescope requirement for lunar observations, which makes large single-aperture
instruments such as the Five-Hundred-Meter Aperture Spherical Radio Telescope
(FAST) well-suited to the technique. In this contribution, we describe the
lunar Askaryan technique and its unique observational requirements. Estimates
of the sensitivity of FAST to both the UHE cosmic ray and neutrino flux are
given, and we describe the methods by which lunar observations with FAST,
particularly if equipped with a broadband phased-array feed, could detect the
flux of UHE cosmic rays.


title: The lunar Askaryan technique with the Square Kilometre Array

abstract:
  The lunar Askaryan technique is a method to study the highest-energy cosmic
rays, and their predicted counterparts, the ultra-high-energy neutrinos. By
observing the Moon with a radio telescope, and searching for the characteristic
nanosecond-scale Askaryan pulses emitted when a high-energy particle interacts
in the outer layers of the Moon, the visible lunar surface can be used as a
detection area. Several previous experiments, at Parkes, Goldstone, Kalyazin,
Westerbork, the ATCA, Lovell, LOFAR, and the VLA, have developed the necessary
techniques to search for these pulses, but existing instruments have lacked the
necessary sensitivity to detect the known flux of cosmic rays from such a
distance. This will change with the advent of the SKA.
  The Square Kilometre Array (SKA) will be the world's most powerful radio
telescope. To be built in southern Africa, Australia and New Zealand during the
next decade, it will have an unsurpassed sensitivity over the key 100 MHz to
few-GHZ band. We introduce a planned experiment to use the SKA to observe the
highest-energy cosmic rays and, potentially, neutrinos. The estimated event
rate will be presented, along with the predicted energy and directional
resolution. Prospects for directional studies with phase 1 of the SKA will be
discussed, as will the major technical challenges to be overcome to make full
use of this powerful instrument. Finally, we show how phase 2 of the SKA could
provide a vast increase in the number of detected cosmic rays at the highest
energies, and thus to provide new insight into their spectrum and origin.


title:
Sensitive neutron detection method using delayed coincidence transitions
  in existing iodine-containing detectors

abstract:
  This letter explains a new, highly sensitive method for the detection of
neutrons, which uses the T$_{1/2}=845$ ns delay in the decay of $^{128}$I at
the 137.8 keV energy level, resulting from the capture of thermal neutrons by
iodine nuclei in NaI and CsI scintillation detectors. The use of delayed
coincidence techniques with a several $\mu {\rm s}$ time frame for delayed
events allows for the highly effective discrimination of neutron events from
any existing background signals. A comparison of ambient neutron measurements
between those identified through the suggested method from a cylindrical, \o$\,
63 \, {\rm mm}\times 63\, {\rm mm}$ NaI(Tl) scintillator and those from a
low-background proportional $^3$He counter experimentally demonstrates the
efficacy of this neutron detection method. For an isotropic, $4\pi$, thermal
neutron flux of 1 ${\rm n}\, {\rm cm}^{-2}\, {\rm s}^{-1}$, the absolute
sensitivity of the NaI detector was found to be $6.5 \pm 1\, {\rm counts}\,
{\rm s}^{-1}$ with a background of $0.8\, {\rm events}\, {\rm day}^{-1}$ and a
delay time frame of $\Delta {\rm t}=1\, \mu $s. The proposed method can provide
low-background experiments, using NaI or CsI, with measurements of the rate and
stability of incoming neutron flux to a greater accuracy than 10$^{-8}\, {\rm
n}\, {\rm cm}^{-2}\, {\rm s}^{-1}$.


title:
Low-entropy states of neutral atoms in polarization-synthesized optical
  lattices

abstract:
  We create low-entropy states of neutral atoms by utilizing a conceptually new
optical-lattice technique that relies on a high-precision, high-bandwidth
synthesis of light polarization. Polarization-synthesized optical lattices
provide two fully controllable optical lattice potentials, each of them
confining only atoms in either one of the two long-lived hyperfine states. By
employing one lattice as the storage register and the other one as the shift
register, we provide a proof of concept using four atoms that selected regions
of the periodic potential can be filled with one particle per site. We expect
that our results can be scaled up to thousands of atoms by employing a
atom-sorting algorithm with logarithmic complexity, which is enabled by
polarization-synthesized optical lattices. Vibrational entropy is subsequently
removed by sideband cooling methods. Our results pave the way for a bottom-up
approach to creating ultralow-entropy states of a many-body system.


title:
Tuning the valley and chiral quantum state of Dirac electrons in van der
  Waals heterostructures

abstract:
  Chirality is a fundamental property of electrons with the relativistic
spectrum found in graphene and topological insulators. It plays a crucial role
in relativistic phenomena, such as Klein tunneling, but it is difficult to
visualize directly. Here we report the direct observation and manipulation of
chirality and pseudospin polarization in the tunneling of electrons between two
almost perfectly aligned graphene crystals. We use a strong in-plane magnetic
field as a tool to resolve the contributions of the chiral electronic states
that have a phase difference between the two components of their vector
wavefunction. Our experiments not only shed light on chirality, but also
demonstrate a technique for preparing graphene's Dirac electrons in a
particular quantum chiral state in a selected valley.


title: Stabilization to trajectories for parabolic equations

abstract:
  The feedback exponential stabilization to trajectories for semilinear
parabolic equations in a given bounded domain is addressed. The controls take
values in a finite-dimensional space and are supported in a small region. Both
internal and boundary controls are considered.


title:
EPR-dictionaries: A practical and fast data structure for constant time
  searches in unidirectional and bidirectional FM-indices

abstract:
  We introduce a new, practical method for conducting an exact search in a uni-
and bidirectional FM index in $O(1)$ time per step while using $O(\log \sigma *
n) + o(\log \sigma * \sigma * n)$ bits of space. This is done by replacing the
binary wavelet tree by a new data structure, the Enhanced Prefixsum Rank
dictionary (EPR-dictionary). We implemented this method in the SeqAn C++
library and experimentally validated our theoretical results. In addition we
compared our implementation with other freely available implementations of
bidirectional indices and show that we are between $\approx 2.6-4.8$ times
faster. This will have a large impact for many bioinformatics applications that
rely on practical implementations of (2)FM indices e.g. for read mapping. To
our knowledge this is the first implementation of a constant time method for a
search step in 2FM indices.


title: Mixed electrical-heat noise spectrum in a quantum dot

abstract:
  Using the Keldysh Green function technique, we calculate the finite-frequency
correlator between the electrical current and the heat current flowing through
a quantum dot connected to reservoirs. At equilibrium, we find that this
quantity, called mixed noise, is linked to the thermoelectric ac-conductance by
the fluctuation-dissipation theorem. Out-of-equilibrium, we discuss its
spectrum and find evidence of the close relationship between the mixed noise
and the thermopower. We study the spectral coherence and identify the
conditions to have a strong correlation between the electrical and heat
currents. The change in the spectral coherence due to the presence of a
temperature gradient between the reservoirs is also highlighted.


title:
Localization of the principal Dirichlet eigenvector in the heavy-tailed
  random conductance model

abstract:
  We study the asymptotic behavior of the principal eigenvector and eigenvalue
of the random conductance Laplacian in a large domain of $\mathbb{Z}^d$ ($d\geq
2$) with zero Dirichlet condition. We assume that the conductances $w$ are
positive i.i.d. random variables, which fulfill certain regularity assumptions
near zero. If $\gamma=\sup \{ q\geq 0\colon \mathbb{E} [w^{-q}]<\infty \}<1/4$,
then we show that for almost every environment the principal Dirichlet
eigenvector asymptotically concentrates in a single site and the corresponding
eigenvalue scales subdiffusively. The threshold $\gamma_{\rm c} = 1/4$ is
sharp. Indeed, other recent results imply that for $\gamma>1/4$ the top of the
Dirichlet spectrum homogenizes. Our proofs are based on a spatial extreme value
analysis of the local speed measure, Borel-Cantelli arguments, the
Rayleigh-Ritz formula, results from percolation theory, and path arguments.


title:
Dirichlet boundary conditions for arbitrary-shaped boundaries in
  stellarator-like magnetic fields for the Flux-Coordinate Independent method

abstract:
  We present a technique for handling Dirichlet boundary conditions with the
Flux Coordinate Independent (FCI) parallel derivative operator with
arbitrary-shaped material geometry in general 3D magnetic fields. The FCI
method constructs a finite difference scheme for $\nabla_\Vert$ by following
field lines between planes and interpolating within planes. Doing so removes
the need for field-aligned coordinate systems that suffer from singularities in
the metric tensor at null points in the magnetic field (or equivalently, when
$q \to \infty$). One cost of this method is that as the field lines are not on
the mesh, they may leave the domain at any point between neighbouring planes,
complicating the application of boundary conditions.
  The Leg Value Fill (LVF) boundary condition scheme presented here involves an
extrapolation/interpolation of the boundary value onto the field line end
point. The usual finite difference scheme can then be used unmodified. We
implement the LVF scheme in BOUT++ and use the Method of Manufactured Solutions
to verify the implementation in a rectangular domain, and show that the error
scaling of the finite difference scheme isn't modified. The use of LVF for
arbitrary wall geometry is outlined.
  We also demonstrate the feasibility of using the FCI approach in
non-axisymmetric configurations for a simple diffusion model in a "straight
stellarator" magnetic field. A Gaussian blob diffuses along the field lines,
tracing out flux surfaces. Dirichlet boundary conditions impose a last closed
flux surface (LCFS) that confines the density. Including a poloidal limiter
moves the LCFS to a smaller radius.
  The expected scaling of the numerical perpendicular diffusion, which is a
consequence of the FCI method, in stellarator-like geometry is recovered. A
novel technique for increasing the parallel resolution during post-processing
is also described.


title: Lattice points in algebraic cross-polytopes and simplices

abstract:
  The number of lattice points $\left| tP \cap \mathbb{Z}^d \right|$, as a
function of the real variable $t>1$ is studied, where $P \subset \mathbb{R}^d$
belongs to a special class of algebraic cross-polytopes and simplices. It is
shown that the number of lattice points can be approximated by an explicitly
given polynomial of $t$ depending only on $P$. The error term is related to a
simultaneous Diophantine approximation problem for algebraic numbers, as in
Schmidt's theorem. The main ingredients of the proof are a Poisson summation
formula for general algebraic polytopes, and a representation of the Fourier
transform of the characteristic function of an arbitrary simplex in the form of
a complex line integral.


title: $\tau$-Rigid Modules from Tilted to Cluster-Tilted Algebras

abstract:
  We study the module categories of a tilted algebra C and the corresponding
cluster-tilted algebra B. In particular, we study which $\tau$-rigid C-modules
are also $\tau$-rigid B-modules.


title:
Gevrey regularity for Navier--Stokes equations under Lions boundary
  conditions

abstract:
  The Navier--Stokes system is considered in a compact Riemannian manifold.
Gevrey class regularity is proven under Lions boundary conditions: in 2D for
the Rectangle, Cylinder, and Hemisphere, and in 3D for the Rectangle. The cases
of the 2D Sphere and 2D and 3D Torus are also revisited.


title:
Areas of Triangles and other Polygons with Vertices from Various
  Sequences

abstract:
  Motivated by Elementary Problem B-1172 in the Fibonacci Quarterly (vol. 53,
no. 3, pg. 273), formulas for the areas of triangles and other polygons having
vertices with coordinates taken from various sequences of integers are
obtained. The sequences discussed are Polygonal number sequences as well as
Fibonacci, Lucas, Jacobsthal, Jacobsthal-Lucas, Pell, Pell-Lucas, and
Generalized Fibonacci sequences. The polygons have vertices with the form
$(p_n,p_{n+k}),\,\, (p_{n+2k},p_{n+3k}),\,\,\dots
,(p_{n+(2m-2)k},p_{n+(2m-1)k)}$.


title:
Efficient entanglement criteria for discrete, continuous, and hybrid
  variables

abstract:
  We provide a method to construct entanglement criteria for arbitrary
multipartite systems of discrete or continuous variables and hybrid
combinations of both. While any set of local operators generates a sufficient
condition for entanglement of arbitrary quantum states, a suitable set leads to
a necessary and sufficient criterion for pure states. The criteria are readily
implementable with existing technology and reveal entanglement that remains
undetected by the respective state-of-the-art methods for discrete and
continuous variables.


title:
Impact of core cladding boundary shape on the waveguide properties of
  hollow core microstructured fibers

abstract:
  In this paper we consider an interaction between the air core modes of hollow
core waveguide microstructures and core cladding boundary walls in various
shapes. The analysis is based on well established models such as the
anti-resonant reflecting optical waveguide model and on the models proposed for
the first time. In particular, we consider the dynamics of light localization
in the polygonalcore cladding boundary wall as dependant on the type of its
discrete rotational symmetry. Based on our findings we analyze the mechanisms
of light localization in the core cladding boundary walls of negative curvature
hollow core microstructured fibers.


title:
Synchronization in dynamical networks of locally coupled self-propelled
  oscillators

abstract:
  Systems of mobile physical entities exchanging information with their
neighborhood can be found in many different situations. The understanding of
their emergent cooperative behaviour has become an important issue across
disciplines, requiring a general conceptual framework in order to harvest the
potential of these systems. We study the synchronization of coupled oscillators
in time-evolving networks defined by the positions of self-propelled agents
interacting in real space. In order to understand the impact of mobility in the
synchronization process on general grounds, we introduce a simple model of
self-propelled hard disks performing persistent random walks in 2$d$ space and
carrying an internal Kuramoto phase oscillator. For non-interacting particles,
self-propulsion accelerates synchronization. The competition between agent
mobility and excluded volume interactions gives rise to a richer scenario,
leading to an optimal self-propulsion speed. We identify two extreme dynamic
regimes where synchronization can be understood from theoretical
considerations. A systematic analysis of our model quantifies the departure
from the latter ideal situations and characterizes the different mechanisms
leading the evolution of the system. We show that the synchronization of
locally coupled mobile oscillators generically proceeds through coarsening
verifying dynamic scaling and sharing strong similarities with the phase
ordering dynamics of the 2$d$ XY model following a quench. Our results shed
light into the generic mechanisms leading the synchronization of mobile agents,
providing a efficient way to understand more complex or specific situations
involving time-dependent networks where synchronization, mobility and excluded
volume are at play.


title: The Renyi Capacity and Center

abstract:
  Renyi's information measures ---the Renyi information, mean, capacity,
radius, and center--- are analyzed relying on the elementary properties of the
Renyi divergence and the power means. The van Erven-Harremoes conjecture is
proved for any positive order and for any set of probability measures on a
given measurable space and a generalization of it is established for the
constrained variant of the problem. The finiteness of the order $\alpha$ Renyi
capacity is shown to imply the continuity of the Renyi capacity on $(0,\alpha]$
and the uniform equicontinuity of the Renyi information, both as a family of
functions of the order indexed by the priors and as a family of functions of
the prior indexed by the orders. The Renyi capacities and centers of various
families of Poisson processes are derived as examples.


title: Neutron star mass limit at $2M_\odot$ supports the existence of a CEP

abstract:
  We point out that the very existence of a "horizontal branch" in the
mass-radius characteristics for neutron stars indicates a strong first-order
phase transition and thus supports the existence of a critical endpoint (CEP)
of first order phase transitions in the QCD phase diagram. This branch would
sample a sequence of hybrid stars with quark matter core, leading to the
endpoint of stable compact star configurations with the highest possible baryon
densities. Since we know of the existence of compact stars with $2M_\odot$,
this hypothetical branch has to lie in the vicinity of this mass value, if it
exists. We report here a correlation between the maximal radius of the
horizontal branch and the pressure at the onset of hadron-to-quark matter phase
transition which is likely to be a universal quantity of utmost relevance to
the upcoming experiments with heavy-ion collisions at NICA and FAIR.


title:
Suppression of Vertical Oscillation and Observation of Flux Improvement
  during Top-up Injection at PLS-II

abstract:
  This paper reports a start-to-end study of suppression of stored beam
oscillation at PLS-II. We report that the fast counter-kicker implemented in
PLS-II suppressed vertical oscillation of the stored beam. During top-up
injection in the magnetic spectroscopy beamline of PLS-II, the stored beam
oscillation was suppressed by a factor of nine, and flux was improved by a
factor of three.


title:
Maximum-Likelihood Detection for Energy-Efficient Timing Acquisition in
  NB-IoT

abstract:
  Initial timing acquisition in narrow-band IoT (NB-IoT) devices is done by
detecting a periodically transmitted known sequence. The detection has to be
done at lowest possible latency, because the RF-transceiver, which dominates
downlink power consumption of an NB-IoT modem, has to be turned on throughout
this time. Auto-correlation detectors show low computational complexity from a
signal processing point of view at the price of a higher detection latency. In
contrast a maximum likelihood cross-correlation detector achieves low latency
at a higher complexity as shown in this paper. We present a hardware
implementation of the maximum likelihood cross-correlation detection. The
detector achieves an average detection latency which is a factor of two below
that of an auto-correlation method and is able to reduce the required energy
per timing acquisition by up to 34%.


title:
The Opium for the Poor Is Opium. Medicare Providers in States with Low
  Income Prescribe High Levels of Opiates

abstract:
  The majority of Medicare opioid prescriptions originate with family practice
and internal medicine providers.
  I show that the average number of Medicare opium prescriptions by these
providers vary strongly by state and that 54% of the variance is accounted for
by the state median household income. I also show that there is a very similar
relationship in opioid claims per capita and per Medicare recipient.
  In all cases Alabama is the state with the most claims and Hawaii is the
state with the least claims.


title: Nonmonotonic Aging and Memory Retention in Disordered Mechanical Systems

abstract:
  We observe non-monotonic aging and memory effects, two hallmarks of glassy
dynamics, in two disordered mechanical systems: crumpled thin sheets and
elastic foams. Under fixed compression, both systems exhibit monotonic
non-exponential relaxation. However, when after a certain waiting time the
compression is partially reduced, both systems exhibit a non-monotonic
response: the normal force first increases over many minutes or even hours
until reaching a peak value, and only then relaxation is resumed. The peak-time
scales linearly with the waiting time, indicating that these systems retain
long-lasting memory of previous conditions. Our results and the measured
scaling relations are in good agreement with a theoretical model recently used
to describe observations of monotonic aging in several glassy systems,
suggesting that the non-monotonic behavior may be generic and that a-thermal
systems can show genuine glassy behavior.


title:
Implementing a Universal Gate Set on a Logical Qubit Encoded in an
  Oscillator

abstract:
  A logical qubit is a two-dimensional subspace of a higher dimensional system,
chosen such that it is possible to detect and correct the occurrence of certain
errors. Manipulation of the encoded information generally requires arbitrary
and precise control over the entire system. Whether based on multiple physical
qubits or larger dimensional modes such as oscillators, the individual elements
in realistic devices will always have residual interactions which must be
accounted for when designing logical operations. Here we demonstrate a holistic
control strategy which exploits accurate knowledge of the Hamiltonian to
manipulate a coupled oscillator-transmon system. We use this approach to
realize high-fidelity (99%, inferred), decoherence-limited operations on a
logical qubit encoded in a superconducting cavity resonator using
four-component cat states. Our results show the power of applying numerical
techniques to control linear oscillators and pave the way for utilizing their
large Hilbert space as a resource in quantum information processing.


title: p-adic functionals on finite-rank torsion-free abelian groups

abstract:
  Let p be a prime and G be a torsion-free abelian group. A homomorphism from G
to the p-adic integers is called a p-adic functional on G. If G has finite
rank, then G can be represented as an inductive limit of an inductive sequence
of free abelian groups of the same rank, and the group of all p-adic
functionals on G is described in terms of this inductive sequence. If this
inductive sequence is stationary--i.e., if the homomorphism is the same at
every stage--then the group of p-adic functionals is described in particularly
simple terms, as a right-submodule that is invariant under the module
homomorphism that this group homomorphism induces. It is shown that the class
consisting of all such stationary inductive limits is closed under
quasi-isomorphism; this strengthens a previous classification result of Dugas.


title:
Fault-Tolerant Gathering of Mobile Robots with Weak Multiplicity
  Detection

abstract:
  There has been a wide interest in designing distributed algorithms for tiny
robots. In particular, it has been shown that the robots can complete certain
tasks even in the presence of faulty robots. In this paper, we focus on
gathering of all non-faulty robots at a single point in presence of faulty
robots. We propose a wait-free algorithm (i.e., no robot waits for other robot
and algorithm instructs each robot to move in every step, unless it is already
at the gathering location), that gathers all non-faulty robots in
semi-synchronous model without any agreement in the coordinate system and with
weak multiplicity detection (i.e., a robot can only detect that either there is
one or more robot at a location) in the presence of at most $n-1$ faulty robots
for $n\geqslant 3$. We show that the required capability for gathering robots
is minimal in the above model, since relaxing it further makes gathering
impossible to solve.
  Also, we introduce an intermediate scheduling model \textit{ASYNC$_{IC}$}
between the asynchronous ( i.e., no instantaneous movement or computation) and
the semi-synchronous (i.e., both instantaneous movement and computation) as the
asynchronous model with instantaneous computation. Then we propose another
algorithm in \textit{ASYNC$_{IC}$} model for gathering all non-faulty robots
with weak multiplicity detection without any agreement on the coordinate system
in the presence of at most $\lfloor n/2\rfloor-2$ faulty robots for $n\geqslant
7$.


title: Introduction to Machine Protection

abstract:
  Protection of accelerator equipment is as old as accelerator technology and
was for many years related to high-power equipment. Examples are the protection
of powering equipment from overheating (magnets, power converters, high-current
cables), of superconducting magnets from damage after a quench and of
klystrons. The protection of equipment from beam accidents is more recent,
although there was one paper that discussed beam-induced damage for the SLAC
linac (Stanford Linear Accelerator Center) as early as in 1967. It is related
to the increasing beam power of high-power proton accelerators, to the emission
of synchrotron light by electron-positron accelerators and to the increase of
energy stored in the beam. Designing a machine protection system requires an
excellent understanding of accelerator physics and operation to anticipate
possible failures that could lead to damage. Machine protection includes beam
and equipment monitoring, a system to safely stop beam operation (e.g. dumping
the beam or stopping the beam at low energy) and an interlock system providing
the glue between these systems. The most recent accelerator, LHC, will operate
with about 3 x 10$^{14}$ protons per beam, corresponding to an energy stored in
each beam of 360 MJ. This energy can cause massive damage to accelerator
equipment in case of uncontrolled beam loss, and a single accident damaging
vital parts of the accelerator could interrupt operation for years. This
lecture will provide an overview of the requirements for protection of
accelerator equipment and introduces various protection systems. Examples are
mainly from LHC and ESS.


title:
Kondo physics of the Anderson impurity model by Distributional Exact
  Diagonalization

abstract:
  The Distributional Exact Diagonalization (DED) scheme is applied to the
description of Kondo physics in the Anderson impurity model. DED maps
Anderson's problem of an interacting impurity level coupled to an infinite bath
onto an ensemble of finite Anderson models, each of which can be solved by
exact diagonalization. An approximation to the self-energy of the original
infinite model is then obtained from the ensemble averaged self-energy. Using
Friedel's sum rule, we show that the particle number constraint, a central
ingredient of the DED scheme, ultimately imposes Fermi liquid behavior on the
ensemble averaged self-energy, and thus is essential for the description of
Kondo physics within DED. Using the Numerical Renormalization Group (NRG)
method as a benchmark, we show that DED yields excellent spectra, both inside
and outside the Kondo regime for a moderate number of bath sites. Only for very
strong correlations ($U/\Gamma\gg10$) does the number of bath sites needed to
achieve good quantitative agreement become too large to be computationally
feasible.


title:
The Infrared Imaging Spectrograph (IRIS) for TMT: optical design of IRIS
  imager with "Co-axis double TMA"

abstract:
  IRIS (InfraRed Imaging Spectrograph) is one of the first-generation
instruments for the Thirty Meter Telescope (TMT). IRIS is composed of a
combination of near-infrared (0.84--2.4 $\mu$m) diffraction limited imager and
integral field spectrograph. To achieve near-diffraction limited resolutions in
the near-infrared wavelength region, IRIS uses the advanced adaptive optics
system NFIRAOS (Narrow Field Infrared Adaptive Optics System) and integrated
on-instrument wavefront sensors (OIWFS). However, IRIS itself has challenging
specifications. First, the overall system wavefront error should be less than
40 nm in Y, z, J, and H-band and 42 nm in K-band over a 34.0 $\times$ 34.0
arcsecond field of view. Second, the throughput of the imager components should
be more than 42 percent. To achieve the extremely low wavefront error and high
throughput, all reflective design has been newly proposed. We have adopted a
new design policy called "Co-Axis double-TMA", which cancels the asymmetric
aberrations generated by "collimator/TMA" and "camera/TMA" efficiently. The
latest imager design meets all specifications, and, in particular, the
wavefront error is less than 17.3 nm and throughput is more than 50.8 percent.
However, to meet the specification of wavefront error and throughput as built
performance, the IRIS imager requires both mirrors with low surface
irregularity after high-reflection coating in cryogenic and high-level Assembly
Integration and Verification (AIV). To deal with these technical challenges, we
have done the tolerance analysis and found that total pass rate is almost 99
percent in the case of gauss distribution and more than 90 percent in the case
of parabolic distribution using four compensators. We also have made an AIV
plan and feasibility check of the optical elements. In this paper, we will
present the details of this optical system.


title:
The Infrared Imaging Spectrograph (IRIS) for TMT: Prototyping of
  cryogenic compatible stage for the Imager

abstract:
  The IRIS Imager requires opt-mechanical stages which are operable under
vacuum and cryogenic environment. Also the stage for the IRIS Imager is
required to survive for 10 years without maintenance. To achieve these
requirements, we decided prototyping of a two axis stage with 80 mm clear
aperture. The prototype was designed as a double-deck stage, upper rotary stage
and lower linear stage. Most of components are selected to take advantage of
heritage from existing astronomical instruments. In contrast, mechanical
components with lubricants such as bearings, linear motion guides and ball
screws were modified to survive cryogenic environment. The performance proving
test was carried out to evaluate errors such as wobbling, rotary and linear
positioning error. We achieved 0.002 $\rm deg_{rms}$ wobbling, 0.08 $\rm
deg_{0-p}$ rotational positioning error and 0.07 $\rm mm_{0-p}$ translational
positioning error. Also durability test under anticipated load condition has
been conducted. In this article, we report the detail of mechanical design,
fabrication, performance and durability of the prototype.


title:
3D $Z_2$ Topological Nodes in Nonsymmorphic Photonic Crystals:
  Ultrastrong Coupling and Anomalous Refraction

abstract:
  We propose to simulate 3D Dirac points and line-nodes with nontrivial $Z_2$
topology in nonsymmorphic all-dielectric photonic-crystals with space-time
reversal symmetry, which can be realized at infrared and microwave frequencies.
Double degeneracy of all Bloch states in high symmetry planes is achieved via
nonsymmorphic screw symmetries despite the fundamental obstacle of no Kramers
degeneracy in photonic crystals. Two orthogonal screw axes lead to 3D $Z_2$
Dirac points on high symmetry Brillouin zone boundary lines. On the other hand,
$Z_2$ line-nodes emerge as protected twofold degeneracy of Bloch bands with
opposite mirror parities on the $k_z=0$ plane. The lowest frequency line-node
is deterministic because of a degenerate-partner switching mechanism guaranteed
by the fundamental properties of Maxwell equations and the nonsymmorphic screw
symmetry. A pair of Fermi arcs with opposite chirality due to $Z_2$ topological
Dirac points emerge below the light-line on (100) and (010)
photonic-crystal-air interfaces. These robust surface states offer an unique
opportunity to realize an "open cavity" with strong interaction between quantum
emitters and engineered vacuum with nontrivial Berry phases --- an important
step toward topological states of strongly interacting bosons. Realistic
calculation for resonant coupling between cavity-photons and phonons in boron
nitride thin film yields ultrastrong coupling with vacuum Rabi splitting
reaching to $23\%$ of photon frequency. We also show that type-II Dirac cones
have anomalous valley selective refraction: birefringence with both positive
and negative refractions for one valley, while no refraction for the other.


title: Out-of-Time-Order Correlation at a Quantum Phase Transition

abstract:
  In this paper we numerically calculate the out-of-time-order correlation
functions in the one-dimensional Bose-Hubbard model. Our study is motivated by
the conjecture that a system with Lyapunov exponent saturating the upper bound
$2\pi/\beta$ will have a holographic dual to a black hole at finite
temperature. We further conjecture that for a many-body quantum system with a
quantum phase transition, the Lyapunov exponent will have a peak in the quantum
critical region where there exists an emergent conformal symmetry and is absent
of well-defined quasi-particles. With the help of a relation between the
R\'enyi entropy and the out-of-time-order correlation function, we argue that
the out-of-time-order correlation function of the Bose-Hubbard model will also
exhibit an exponential behavior at the scrambling time. By fitting the
numerical results with an exponential function, we extract the Lyapunov
exponents in the one-dimensional Bose-Hubbard model across the quantum critical
regime at finite temperature. Our results on the Bose-Hubbard model support the
conjecture. We also compute the butterfly velocity and propose how the echo
type measurement of this correlator in the cold atom realizations of the
Bose-Hubbard model without inverting the Hamiltonian.


title: A translation generalized quadrangle in characteristic $\ne 0$ is linear

abstract:
  It is a long-standing conjecture from the 1970s that every translation
generalized quadrangle is linear, that is, has an endomorphism ring which is a
division ring (or, in geometric terms, that has a projective representation).
We show that any translation generalized quadrangle $\Gamma$ is ideally
embedded in a translation quadrangle which is linear. This allows us to weakly
represent any such $\Gamma$ in projective space, and moreover, to have a
well-defined notion of "characteristic" for these objects. We then show that
each translation quadrangle in positive characteristic indeed is linear.


title: A branching random walk among disasters

abstract:
  We consider a branching random walk in a random space-time environment of
disasters where each particle is killed when meeting a disaster. This extends
the model of the "random walk in a disastrous random environment" introduced by
[15]. We obtain a criterion for positive survival probability, see Theorem 1.
The proofs for the subcritical and the supercritical cases follow standard
arguments, which involve moment methods and a comparison with an embedded
branching process with i.i.d. offspring distributions. The proof of almost sure
extinction in the critical case is more difficult and uses the techniques from
[8]. We also show that, in the case of survival, the number of particles grows
exponentially fast.


title:
Proceedings of the Second Summer School on Argumentation: Computational
  and Linguistic Perspectives (SSA'16)

abstract:
  This volume contains the thesis abstracts presented at the Second Summer
School on Argumentation: Computational and Linguistic Perspectives (SSA'2016)
held on September 8-12 in Potsdam, Germany.


title:
A Fault-Tolerant Sequentially Consistent DSM With a Compositional
  Correctness Proof

abstract:
  We present the SC-ABD algorithm that implements sequentially consistent
distributed shared memory (DSM). The algorithm tolerates that less than half of
the processes are faulty (crash-stop). Compared to the multi-writer ABD
algorithm, SC-ABD requires one instead of two round-trips of communication to
perform a write operation, and an equal number of round-trips (two) to perform
a read operation. Although sequential consistency is not a compositional
consistency condition, the provided correctness proof is compositional.


title: Dehn filling and the Thurston norm

abstract:
  For a compact, orientable, irreducible 3-manifold with toroidal boundary that
is not the product of a torus and an interval or a cable space, each boundary
torus has a finite set of slopes such that, if avoided, the Thurston norm of a
Dehn filling behaves predictably. More precisely, for all but finitely many
slopes, the Thurston norm of a class in the second homology of the filled
manifold plus the so-called winding norm of the class will be equal to the
Thurston norm of the corresponding class in the second homology of the unfilled
manifold. This generalizes a result of Sela and is used to answer a question of
Baker-Motegi concerning the Seifert genus of knots obtained by twisting a given
initial knot along an unknot which links it.


title:
A co-dimensional 3 sub-Riemannian structure on Gromoll-Meyer exotic
  sphere

abstract:
  We construct a co-dimension $3$ completely non-holonomic sub-bundle on the
Gromoll-Meyer exotic $7$ sphere based on its realization as a base space of a
Sp(2)-principal bundle with the structure group Sp(1). The same method is valid
for constructing a co-dimension 3 completely non-holonomic sub-bundle on the
standard 7 sphere (or more general on a $4n+3$ dimensional standard sphere). In
the latter case such a construction based on the Hopf bundle is well-known. Our
method provides an alternated simple proof for the standard sphere
$\mathbb{S}^7$.


title: Polynomial representations of $C^*$-algebras and their applications

abstract:
  This is a sequel to our paper on nonlinear completely positive maps and
dilation theory for real involutive algebras, where we have reduced all
representation classification problems to the passage from a $C^*$-algebra
${\mathcal A}$ to its symmetric powers $S^n({\mathcal A})$, resp., to
holomorphic representations of the multiplicative $*$-semigroup $({\mathcal
A},\cdot)$. Here we study the correspondence between representations of
${\mathcal A}$ and of $S^n({\mathcal A})$ in detail. As $S^n({\mathcal A})$ is
the fixed point algebra for the natural action of the symmetric group $S_n$ on
${\mathcal A}^{\otimes n}$, this is done by relating representations of
$S^n({\mathcal A})$ to those of the crossed product ${\mathcal A}^{\otimes n}
\rtimes S_n$ in which it is a hereditary subalgebra. For $C^*$-algebras of type
I, we obtain a rather complete description of the equivalence classes of the
irreducible representations of $S^n({\mathcal A})$ and we relate this to the
Schur--Weyl theory for $C^*$-algebras. Finally we show that if ${\mathcal
A}\subseteq B({\mathcal H})$ is a factor of type II or III, then its
corresponding multiplicative representation on ${\mathcal H}^{\otimes n}$ is a
factor representation of the same type, unlike the classical case ${\mathcal
A}=B({\mathcal H})$.


title: Who would invest only in the risk-free asset?

abstract:
  Within the setup of continuous-time semimartingale financial markets, we show
that a multiprior Gilboa-Schmeidler minimax expected utility maximizer forms a
portfolio consisting only of the riskless asset if and only if among the
investor's priors there exists a probability measure under which all admissible
wealth processes are supermartingales. Furthermore, we show that under a
certain attainability condition (which is always valid in finite or complete
markets) this is also equivalent to the existence of an equivalent (local)
martingale measure among the investor's priors. As an example, we generalize a
no betting result due to Dow and Werlang.


title:
Shifted symmetric functions and multirectangular coordinates of Young
  diagrams

abstract:
  In this paper, we study shifted Schur functions $S_\mu^\star$, as well as a
new family of shifted symmetric functions $\mathfrak{K}_\mu$ linked to Kostka
numbers. We prove that both are polynomials in multi-rectangular coordinates,
with nonnegative coefficients when written in terms of falling factorials. We
then propose a conjectural generalization to the Jack setting. This conjecture
is a lifting of Knop and Sahi's positivity result for usual Jack polynomials
and resembles recent conjectures of Lassalle. We prove our conjecture for
one-part partitions.


title: Identities involving weighted Catalan, Schroder and Motzkin paths

abstract:
  In this paper, we investigate the weighted Catalan, Motzkin and Schr\"oder
numbers together with the corresponding weighted paths. The relation between
these numbers is illustrated by three equations, which also lead to some known
and new interesting identities. To show these three equations, we provide
combinatorial proofs. One byproduct is to find a bijection between two sets of
Catalan paths: one consisting of those with $k$ valleys, and the other
consisting of $k$ $\mathbf{N}$ steps in even positions.


title: Beam Dynamics and Beam Losses - Circular Machines

abstract:
  A basic introduction to transverse and longitudinal beam dynamics as well as
the most relevant beam loss mechanisms in circular machines will be presented
in this lecture. This lecture is intended for physicists and engineers with
little or no knowledge of this subject.


title: ASP for Minimal Entailment in a Rational Extension of SROEL

abstract:
  In this paper we exploit Answer Set Programming (ASP) for reasoning in a
rational extension SROEL-R-T of the low complexity description logic SROEL,
which underlies the OWL EL ontology language. In the extended language, a
typicality operator T is allowed to define concepts T(C) (typical C's) under a
rational semantics. It has been proven that instance checking under rational
entailment has a polynomial complexity. To strengthen rational entailment, in
this paper we consider a minimal model semantics. We show that, for arbitrary
SROEL-R-T knowledge bases, instance checking under minimal entailment is
\Pi^P_2-complete. Relying on a Small Model result, where models correspond to
answer sets of a suitable ASP encoding, we exploit Answer Set Preferences (and,
in particular, the asprin framework) for reasoning under minimal entailment.
The paper is under consideration for acceptance in Theory and Practice of Logic
Programming.


title: An $\widetilde{O}(n)$ Queries Adaptive Tester for Unateness

abstract:
  We present an adaptive tester for the unateness property of Boolean
functions. Given a function $f:\{0,1\}^n \to \{0,1\}$ the tester makes $O(n
\log(n)/\epsilon)$ adaptive queries to the function. The tester always accepts
a unate function, and rejects with probability at least 0.9 if a function is
$\epsilon$-far from being unate.


title:
On the efficiency of techniques for the reduction of impulsive noise in
  astronomical images

abstract:
  The impulsive noise in astronomical images originates from various sources.
It develops as a result of thermal generation in pixels, collision of cosmic
rays with image sensor or may be induced by high readout voltage in Electron
Multiplying CCD (EMCCD). It is usually efficiently removed by employing the
dark frames or by averaging several exposures. Unfortunately, there are some
circumstances, when either the observed objects or positions of impulsive
pixels evolve and therefore each obtained image has to be filtered
independently. In this article we present an overview of impulsive noise
filtering methods and compare their efficiency for the purpose of astronomical
image enhancement. The employed set of noise templates consists of dark frames
obtained from CCD and EMCCD cameras working on ground and in space. The
experiments conducted on synthetic and real images, allowed for drawing
numerous conclusions about the usefulness of several filtering methods for
various: (1) widths of stellar profiles, (2) signal to noise ratios, (3) noise
distributions and (4) applied imaging techniques. The results of presented
evaluation are especially valuable for selection of the most efficient
filtering schema in astronomical image processing pipelines.


title:
Excitons in topological Kondo insulators - theory of thermodynamic and
  transport anomalies in SmB$_6$

abstract:
  Kondo insulating materials lie outside the usual dichotomy of weakly versus
correlated - band versus Mott - insulators. They are metallic at high
temperatures but resemble band insulators at low temperatures because of the
opening of an interaction induced band gap. The first discovered Kondo
insulator (KI) SmB$_6$ has been predicted to form a topological KI (TKI) which
mimics a topological insulator at low temperatures. However, since its
discovery thermodynamic and transport anomalies have been observed that have
defied a theoretical explanation. Enigmatic signatures of collective modes
inside the charge gap are seen in specific heat, thermal transport and quantum
oscillation experiments in strong magnetic fields. Here, we show that TKIs are
susceptible to the formation of excitons and magneto-excitons. These charge
neutral composite particles can account for long-standing anomalies in SmB$_6$
which is crucial for the identification of bulk topological signatures.


title:
Probing the interaction between dark matter and dark energy in the
  presence of massive neutrinos

abstract:
  We consider the possibility of an interaction in the dark sector in the
presence of massive neutrinos, and study the observational constraints on three
different scenarios of massive neutrinos using the most recent CMB anisotropy
data in combination with type Ia supernovae, baryon acoustic oscillations, and
Hubble parameter measurements. When a sterile neutrino is introduced in the
interacting dark sector scenario in addition to the standard model prediction
of neutrinos, we find that the coupling parameter, characterizing the
interaction between dark matter and dark energy, is non-zero at 2$\sigma$
confidence level. The interaction model with sterile neutrino is also found to
be a promising one to alleviate the current tension on Hubble constant. We do
not find the evidence for a coupling in the dark sector when the possibility of
a sterile neutrino is discarded.


title: Zeroes and rational points of analytic functions

abstract:
  For an analytic function $f(z)=\sum_{k=0}^\infty a_kz^k$ on a neighbourhood
of a closed disc $D\subset {\bf C}$, we give assumptions, in terms of the
Taylor coefficients $a_k$ of $f$, under which the number of intersection points
of the graph $\Gamma_f$ of $f_{\vert D}$ and algebraic curves of degree $d$ is
polynomially bounded in $d$. In particular, we show these assumptions are
satisfied for random power series, for some explicit classes of lacunary
series, and for solutions of linear differential equations with coefficients in
${\bf Q}[z]$. As a consequence, for any function $f$ in these families,
$\Gamma_f$ has less than $\beta \log^\alpha T$ rational points of height at
most $T$, for some $\alpha, \beta >0$.


title: Beam Loss in Linacs

abstract:
  Beam loss is a critical issue in high-intensity accelerators, and much effort
is expended during both the design and operation phases to minimize the loss
and to keep it to manageable levels. As new accelerators become ever more
powerful, beam loss becomes even more critical. Linacs for H- ion beams, such
as the one at the Oak Ridge Spallation Neutron Source, have many more loss
mechanisms compared to H+ (proton) linacs, such as the one being designed for
the European Spallation Neutron Source. Interesting H- beam loss mechanisms
include residual gas stripping, H+ capture and acceleration, field stripping,
black-body radiation and the recently discovered intra-beam stripping
mechanism. Beam halo formation, and ion source or RF turn on/off transients,
are examples of beam loss mechanisms that are common for both H+ and H-
accelerators. Machine protection systems play an important role in limiting the
beam loss.


title:
Making SPIFFI SPIFFIER: Upgrade of the SPIFFI instrument for use in ERIS
  and performance analysis from re-commissioning

abstract:
  SPIFFI is an AO-fed integral field spectrograph operating as part of SINFONI
on the VLT, which will be upgraded and reused as SPIFFIER in the new VLT
instrument ERIS. In January 2016, we used new technology developments to
perform an early upgrade to optical subsystems in the SPIFFI instrument so
ongoing scientific programs can make use of enhanced performance before ERIS
arrives in 2020. We report on the upgraded components and the performance of
SPIFFI after the upgrade, including gains in throughput and spatial and
spectral resolution. We show results from re-commissioning, highlighting the
potential for scientific programs to use the capabilities of the upgraded
SPIFFI. Finally, we discuss the additional upgrades for SPIFFIER which will be
implemented before it is integrated into ERIS.


title: Gordon type Theorem for measure perturbation

abstract:
  Generalizing the concept of Gordon potentials to measures we prove a version
of Gordon's theorem for measures as potentials and show absence of eigenvalues
for these one-dimensional Schr\"odinger operators.


title: Efficient electrical spin readout of NV- centers in diamond

abstract:
  Using pulsed photoionization the coherent spin manipulation and echo
formation of ensembles of NV- centers in diamond are detected electrically
realizing contrasts of up to 17 %. The underlying spin-dependent ionization
dynamics are investigated experimentally and compared to Monte-Carlo
simulations. This allows the identification of the conditions optimizing
contrast and sensitivity which compare favorably with respect to optical
detection.


title: Applied-Field Effects on Benzene Transmission

abstract:
  By expressing the discrete Schrodinger equation as a second-order
finite-difference equation with constant coefficients, the renormalization
equations for substituted benzene dimers are derived via the c_n-coefficient
elimination procedure. On subjecting the benzene molecule to a linear applied
field, the resulting field-modified site energies are obtained, by projecting
the site-energy locations onto a corresponding benzene dimer axis.
Incorporating these modified site energies into the Lippmann-Schwinger
scattering theory, enables the field effect to manifest itself in the
substituted benzene electron transmission spectral function T(E). Variations in
the T(E) energy spectra, arising from increases in the applied field gradient
f, are described for each substituted benzene, and comparison made between
their various patterns' behaviours. A common feature of the T(E) curves is
their shifts to lower energies, as f increases to a calculated limiting value.


title:
A Matrix-free Preconditioner for the Helmholtz Equation based on the
  Fast Multipole Method

abstract:
  Fast multipole methods (FMM) were originally developed for accelerating
$N$-body problems for particle-based methods. FMM is more than an $N$-body
solver, however. Recent efforts to view the FMM as an elliptic Partial
Differential Equation (PDE) solver have opened the possibility to use it as a
preconditioner for a broader range of applications. FMM can solve Helmholtz
problems with optimal $\mathcal{O}(N \log N)$ complexity, has compute-bound
inner kernels, and highly asynchronous communication patterns. The combination
of these features makes FMM an interesting candidate as a preconditioner for
sparse solvers on architectures of the future. The use of FMM as a
preconditioner allows us to use lower order multipole expansions than would be
required as a solver because individual solves need not be accurate. This
reduces the amount of computation and communication significantly and makes the
time-to-solution competitive with state-of-the-art preconditioners.
Furthermore, the high asynchronicity of FMM allows it to scale to much larger
core counts than factorization-based and multilevel methods. We describe our
tests in reproducible details with freely available codes.


title: High-Intensity Synchrotron Radiation Effects

abstract:
  Various effects of intense synchrotron radiation on the performance of
particle accelerators, especially for storage rings, are discussed. Following a
brief introduction to synchrotron radiation, the basic concepts of heat load,
gas load, electron emission, and the countermeasures against these effects are
discussed.


title: Dirichlet forms for singular diffusion on graphs

abstract:
  We describe operators driving the time evolution of singular diffusion on
finite graphs whose vertices are allowed to carry masses. The operators are
defined by the method of quadratic forms on suitable Hilbert spaces. The model
also covers quantum graphs and discrete Laplace operators.


title:
Restricted Euler dynamics along trajectories of small inertial particles
  in turbulence

abstract:
  The fate of small particles in turbulent flows depends strongly on the
surrounding fluid's velocity gradient properties such as rotation and
strain-rates. For non-inertial (fluid) particles, the Restricted Euler model
provides a simple, low-dimensional dynamical system representation of
Lagrangian evolution of velocity gradients in fluid turbulence, at least for
short times. Here we derive a new restricted Euler dynamical system for the
velocity gradient evolution of inertial particles such as solid particles in a
gas or droplets and bubbles in turbulent liquid flows. The model is derived in
the limit of small (sub Kolmogorov scale) particles and low Stokes number. The
system exhibits interesting fixed points, stability and invariant properties.
Comparisons with data from Direct Numerical Simulations show that the model
predicts realistic trends such as the tendency of increased straining over
rotation along heavy particle trajectories and, for light particles such as
bubbles, the tendency of reduced self-stretching of strain-rate.


title:
Spin-resolved interference due to Majorana state on interface between
  normal and superconducting leads

abstract:
  We investigate the subgap spectrum and transport properties of the quantum
dot placed on interface between metallic and superconducting leads and
additionally side-coupled to the edge of topological superconducting (TS)
chain, hosting the Majorana quasiparticle. Due to chiral nature of the Majorana
states only one spin component, say $\uparrow$, of the quantum dot electrons is
directly hybridized with the TS wire. We study the spin-selective
interferometric patterns driven by the Majorana quasiparticle. The proximity
induced on-dot pairing effectively transmits the interference onto both spin
components, but each of them is characterized by completely different (even
opposite) signatures. To explain their origin we confront our results with the
toy model, where TS chain is replaced by the usual quantum and the tunneling of
$\downarrow$ electrons is prohibited. We also address unique interplay of the
Majorana and Kondo features, both appearing at zero energy.


title: Thermodynamics. Using Affinities to define reversible processes

abstract:
  In this article a definition of reversible processes in terms of differences
in intensive Thermodynamics properties (Affinities) is proposed. This
definition makes it possible to both define reversible processes before
introducing the concept of entropy and avoid the circularity problem that
follows from the Clausius definition of entropy changes. The convenience of
this new definition compared to those commonly found in textbooks is
demonstrated with examples.


title:
Number Series of Atoms, Interatomic Bonds and Interface Bonds Defining
  Zinc-Blende Nanocrystals as Function of Size, Shape and Surface Orientation:
  Analytic Tools to Interpret Solid State Spectroscopy Data

abstract:
  Semiconductor nanocrystals (NCs) experience stress and charge transfer by
embedding materials or ligands and impurity atoms. In return, the environment
of NCs experiences a NC stress response which may lead to matrix deformation
and propagated strain. Up to now, there is no universal gauge to evaluate the
stress impact on NCs and their response as a function of NC size
$d_{\mathrm{NC}}$. I deduce geometrical number series as analytical tools to
obtain the number of NC atoms $N_{\mathrm{NC}}(d_{\mathrm{NC}}[i])$, bonds
between NC atoms $N\mathrm{_{bnd}}(d_{\mathrm{NC}}[i])$ and interface bonds
$N\mathrm{_{IF}}(d_{\mathrm{NC}}[i])$ for seven high symmetry zinc-blende (zb)
NCs with low-index faceting: {001} cubes, {111} octahedra, {110} dodecahedra,
{001}-{111} pyramids, {111} tetrahedra, {111}-{001} quatrodecahedra and
{001}-{111} quadrodecahedra. The fundamental insights into NC structures
revealed here allow for major advancements in data interpretation and
understanding of zb- and diamond-lattice based nanomaterials. The analytical
number series can serve as a standard procedure for stress evaluation in solid
state spectroscopy due to their deterministic nature, easy use and general
applicability over a wide range of spectroscopy methods as well as NC sizes,
forms and materials.


title: Ranks of Maharam algebras

abstract:
  Solving a well-known problem of Maharam, Talagrand [17] constructed an
exhaustive non uniformly exhaustive submeasure, thus also providing the first
example of a Maharam algebra that is not a measure algebra. To each exhaustive
submeasure one can canonically assign a certain countable ordinal, its
exhaustivity rank. In this paper, we use carefully constructed Schreier
families and norms derived from them to provide examples of exhaustive
submeasures of arbitrary high exhaustivity rank. This gives rise to uncountably
many non isomorphic separable atomless Maharam algebras.


title: Almost sure purely singular continuous spectrum for quasicrystal models

abstract:
  We review recent developments in the spectral theory of continuum
one-dimensional quasicystals, yielding purely singular continuous spectrum for
these Schr\"odinger operators. Allowing measures as potentials we can
generalize some results to very singular potentials, including Kronig-Penney
type models.


title:
The poles of Igusa zeta integrals and the unextendability of
  semi-invariant distributions

abstract:
  We investigate the relationship between the poles of Igusa zeta integrals and
the unextendability of semi-invariant distributions. Under some algebraic
conditions, we obtain an upper bound for the order of the poles of Igusa zeta
integral, and by using the order of the poles we give a criterion on the
unextendability of semi-invariant distributions. A key ingredient of our method
is the idea of generalized semi-invariant distributions.


title: Stochastic Bifurcations in the Nonlinear Parallel Ising Model

abstract:
  We investigate the phase transitions of a nonlinear, parallel version of the
Ising model, characterized by an antiferromagnetic linear coupling and
ferromagnetic nonlinear one. This model arises in problems of opinion
formation. The mean-field approximation shows chaotic oscillations, by changing
the couplings or the connectivity. The spatial model shows bifurcations in the
average magnetization, similar to what seen in the mean-field approximation,
induced by the change of the topology, after rewiring short-range to long-range
connection, as predicted by the small-world effect. These coherent periodic and
chaotic oscillations of the magnetization reflect a certain degree of
synchronization of the spins, induced by long-range couplings. Similar
bifurcations may be induced in the randomly connected model by changing the
couplings or the connectivity and also the dilution (degree of asynchronism) of
the updating. We also examined the effects of inhomogeneity, mixing
ferromagnetic and antiferromagnetic coupling, which induces an unexpected
bifurcation diagram with a "bubbling" behaviour, as also happens for dilution.


title: Higher Hickerson formula

abstract:
  Hickerson made an explicit formula for Dedekind sums $s(p,q)$ in terms of the
continued fraction of $p/q$. We develop analogous formula for generalized
Dedekind sums $s_{i,j}(p,q)$ defined in association with the
$x^{i}y^{j}$-coefficient of the Todd power series of the lattice cone in
$\Bbb{R}^2$ generated by $(1,0)$ and $(p,q)$. The formula generalizes
Hickerson's original one and reduces to Hickerson's for $i=j=1$. In the
formula, generalized Dedekind sums are divided into two parts: the integral
$s^I_{ij}(p,q)$ and the fractional $s^R_{ij}(p,q)$. We apply the formula to
Siegel's formula for partial zeta values at a negative integer and obtain a new
expression which involves only $s^I_{ij}(p,q)$ the integral part of generalized
Dedekind sums. This formula directly generalize Meyer's formula for the special
value at $0$. Using our formula, we present the table of the partial zeta value
at $s=-1$ and $-2$ in more explicit form. Finally, we present another
application on the equidistribution property of the fractional parts of the
graph $\Big{(}\frac{p}{q},R_{i+j}q^{i+j-2} s_{ij}(p,q)\Big{)}$ for a certain
integer $R_{i+j}$ depending on $i+j$.


title:
Experimental test of photonic entanglement in accelerated reference
  frames

abstract:
  The quantization of the electromagnetic field has successfully paved the way
for the development of the Standard Model of Particle Physics and has
established the basis for quantum technologies. Gravity, however, continues to
hold out against physicists' efforts of including it into the framework of
quantum theory. Experimental techniques in quantum optics have only recently
reached the precision and maturity required for the investigation of quantum
systems under the influence of gravitational fields. Here, we report on
experiments in which a genuine quantum state of an entangled photon pair was
exposed to a series of different accelerations. We measure an entanglement
witness for $g$ values ranging from 30 mg to up to 30 g - under free-fall as
well on a spinning centrifuge - and have thus derived an upper bound on the
effects of uniform acceleration on photonic entanglement. Our work represents
the first quantum optics experiment in which entanglement is systematically
tested in geodesic motion as well as in accelerated reference frames with
acceleration a>>g = 9.81 m/s^2.


title:
Reconstruction of an effective magnon mean free path distribution from
  spin Seebeck measurements in thin films

abstract:
  A thorough understanding of the mean-free-path (MFP) distribution of the
energy carriers is crucial to engineer and tune the transport properties of
materials. In this context, a significant body of work has investigated the
phonon and electron MFP distribution, however, similar studies of the magnon
MFP distribution have not been carried out so far. In this work, we used
thickness-dependence measurements of the longitudinal spin Seebeck (LSSE)
effect of yttrium iron garnet films to reconstruct the cumulative distribution
of a SSE related effective magnon MFP. By using the experimental data reported
by Guo et al. [Phys. Rev. X 6, 031012 (2016)], we adapted the phonon MFP
reconstruction algorithm proposed by A.J. Minnich, [Phys. Rev. Lett. 109,
205901 (2012)] and apply it to magnons. The reconstruction showed that magnons
with different MFP contribute in different manner to the total LSSE and the
effective magnon MFP distribution spreads far beyond their typical averaged
values.


title: Evidence for marginal stability in emulsions

abstract:
  We report the first measurements of the effect of pressure on vibrational
modes in emulsions, which serve as a model for soft frictionless spheres at
zero temperature. As a function of the applied pressure, we find that the
density of states D(omega) exhibits a low-frequency cutoff omega*, which scales
linearly with the number of extra contacts per particle dz. Moreover, for
omega<omega*, D(omega)~ omega^2/omega*^2; a quadratic behavior whose prefactor
is larger than what is expected from Debye theory. This surprising result
agrees with recent theoretical findings. Finally, the degree of localization of
the softest low frequency modes increases with compression, as shown by the
participation ratio as well as their spatial configurations. Overall, our
observations show that emulsions are marginally stable and display
non-plane-wave modes up to vanishing frequencies.


title: Beam-Material Interaction

abstract:
  Th is paper is motivated by the growing importance of better understanding of
the phenomena and consequences of high- intensity energetic particle beam
interactions with accelerator, generic target , and detector components. It
reviews the principal physical processes of fast-particle interactions with
matter, effects in materials under irradiation, materials response, related to
component lifetime and performance, simulation techniques, and methods of
mitigating the impact of radiation on the components and envir onment in
challenging current and future application


title:
Low-Complexity Massive MIMO Subspace Estimation and Tracking from
  Low-Dimensional Projections

abstract:
  Massive MIMO is a variant of multiuser MIMO, where the number of antennas $M$
at the base-station is large, and generally much larger than the number of
spatially multiplexed data streams to/from the users. It has been observed that
in many realistic propagation scenarios as well as in spatially correlated
channel models used in standardizations, although the user channel vectors have
a very high-dim $M$, they lie on low-dim subspaces due to their limited angular
spread. This low-dim subspace structure remains stable across many coherence
blocks and can be exploited in several ways to improve the system performance.
A main challenge, however, is to estimate this signal subspace from samples of
users' channel vectors as fast and efficiently as possible. In a recent work,
we addressed this problem and proposed a very effective novel algorithm
referred to as Approximate Maximum-Likelihood (AML), which was formulated as a
semi-definite program (SDP). In this paper, we address two problems left open
in our previous work: computational complexity and tracking. The algorithm
proposed in this paper is reminiscent of Multiple Measurement Vectors (MMV)
problem in Compressed Sensing and is proved to be equivalent to the AML
Algorithm for sufficiently dense angular grids. It has also a very low
computational complexity and is able to track sharp transitions in the channel
statistics very quickly. Although mainly motivated by massive MIMO
applications, our proposed algorithm is of independent interest in other
related subspace estimation applications. We assess the estimation/tracking
performance of our proposed algorithm empirically via numerical simulations,
especially in practically relevant situations where a direct implementation of
the SDP would be infeasible in real-time. We also compare the performance of
our algorithm with other related subspace estimation algorithms in the
literature.


title: Temperature chaos in some spherical mixed $p$-spin models

abstract:
  We give two types of examples of the spherical mixed even-$p$-spin models for
which chaos in temperature holds. These complement some known results for the
spherical pure $p$-spin models and for models with Ising spins. For example, in
contrast to a recent result of Subag who showed absence of chaos in temperature
in the spherical pure $p$-spin models for $p\geq 3$, we show that even a
smaller order perturbation induces temperature chaos.


title: Genuine Non-Self-Averaging and Ultra-Slow Convergence in Gelation

abstract:
  In irreversible aggregation processes droplets or polymers of microscopic
size successively coalesce until a large cluster of macroscopic scale forms.
This gelation transition is widely believed to be self-averaging, meaning that
the order parameter (the relative size of the largest connected cluster)
attains well-defined values upon ensemble averaging with no sample-to-sample
fluctuations in the thermodynamic limit. Here, we report on anomalous gelation
transition types. Depending on the growth rate of the largest clusters, the
gelation transition can show very diverse patterns as a function of the control
parameter, which includes multiple stochastic discontinuous transitions,
genuine non-self-averaging and ultra-slow convergence of the transition point.
Our framework may be helpful in understanding and controlling gelation.


title: The Second Arecibo Search for 5 GHz Radio Flares from Ultracool Dwarfs

abstract:
  We describe our second installment of the 4.75 GHz survey of ultracool dwarfs
(UCDs) conducted with the Arecibo radio telescope, which has observed 27 such
objects and resulted in the detection of sporadic flaring from the T6 dwarf,
WISEPC J112254.73+255021.5. We also present follow up observations of the first
radio-emitting T dwarf, 2MASS J10475385+2124234, a tentatively identified radio
emitting L1 dwarf, 2MASS J1439284+192915, and the known radio-flaring source,
2MASS J13142039+132011 AB. Our new data indicate that 2MASS J1439284+192915 is
not a radio flaring source. The overall detection rate of our unbiased survey
for radio-flaring UCDs is ~5% for new sources, with a detection rate for each
spectral class of ~5-10%. Evidently, radio luminosity of the UCDs does not
appear to monotonically decline with spectral type from M7 dwarfs to giant
planets, in contradiction to theories of the magnetic field generation and
internal structure of these objects. Along with other, recently published
results, our data exemplify the unique value of using radio surveys to reveal
and study properties of substellar magnetic activity.


title:
Non-perturbative running of renormalization constants from correlators
  in coordinate space using step scaling

abstract:
  Working in a quenched setup with Wilson twisted mass valence fermions, we
explore the possibility to compute non-perturbatively the step scaling function
using the coordinate (X-space) renormalization scheme. This scheme has the
advantage of being on-shell and gauge invariant. The step scaling method allows
us to calculate the running of the renormalization constants of quark bilinear
operators. We describe here the details of this calculation. The aim of this
exploratory study is to identify the feasibility of the X-space scheme when
used in small volume simulations required by the step scaling technique.
Eventually, we translate our final results to the continuum MSbar scheme and
compare against four-loop analytic formulae finding satisfactory agreement.


title:
Optical Properties of Amorphous Silicon Quantum Dots(a-Si QDs) with
  various dot size using Extended H\"uckel Theory

abstract:
  A high quality amorphous silicon (a-Si) nanostructures has grown
experimentally to study the origin of light emission and the quantum
confinement effect in a-Si. The quantum confinement effect increases the band
gap of material as the size of quantum structure decreases, which results in a
blue shift in optical luminescence and energy absorption. Here we demonstrate
this effect using extended H\"uckel method to calculate fundamental band gap
and optical absorption energy of a-Si samples with various dot sizes. As
result, when the dot size was decreased from 2.2 to 1.0 nm, the absorption
spectra peak shifted toward higher energy from 2.278 eV to 3.856 eV.


title:
Using a terrestrial laser scanner to characterize vegetation-induced
  flow resistance in a controlled channel

abstract:
  Vegetation characteristics providing spatial heterogeneity at the channel
reach scale can produce complex flow patterns and the relationship between
plant patterns morphology and flow resistance is still an open question (Nepf
2012). Unlike experiments in laboratory, measuring the vegetation
characteristics related to flow resistance on open channel in situ is
difficult. Thanks to its high resolution and light weight, scanner lasers allow
now to collect in situ 3D vegetation characteristics. In this study we used a
1064 nm usual Terrestrial Laser Scanner (TLS) located 5 meters at nadir above a
8 meters long equipped channel in order to both i) characterize the vegetation
structure heterogeneity within the channel form a single scan (blockage factor,
canopy height) and ii) to measure the 2D water level all over the channel
during steady flow within a few seconds scan. This latter measuring system was
possible thanks to an additive dispersive product sprinkled at the water
surface. Vegetation characteristics and water surfaces during steady flows from
6 different plant spatial design on channel bottom for 4 plant species were
thus measured. Vegetation blockage factors at channel scale were estimated from
TLS points clouds and analyzed.


title:
Interpolated Discretized Embedding of Single Vectors and Vector Pairs
  for Classification, Metric Learning and Distance Approximation

abstract:
  We propose a new embedding method for a single vector and for a pair of
vectors. This embedding method enables: a) efficient classification and
regression of functions of single vectors; b) efficient approximation of
distance functions; and c) non-Euclidean, semimetric learning. To the best of
our knowledge, this is the first work that enables learning any general,
non-Euclidean, semimetrics. That is, our method is a universal semimetric
learning and approximation method that can approximate any distance function
with as high accuracy as needed with or without semimetric constraints. The
project homepage including code is at: http://www.ariel.ac.il/sites/ofirpele/ID


title: Boosting as a kernel-based method

abstract:
  Boosting combines weak (biased) learners to obtain effective learning
algorithms for classification and prediction. In this paper, we show a
connection between boosting and kernel-based methods, highlighting both
theoretical and practical applications. In the context of $\ell_2$ boosting, we
start with a weak linear learner defined by a kernel $K$. We show that boosting
with this learner is equivalent to estimation with a special {\it boosting
kernel} that depends on $K$, as well as on the regression matrix, noise
variance, and hyperparameters. The number of boosting iterations is modeled as
a continuous hyperparameter, and fit along with other parameters using standard
techniques.
  We then generalize the boosting kernel to a broad new class of boosting
approaches for more general weak learners, including those based on the
$\ell_1$, hinge and Vapnik losses. The approach allows fast hyperparameter
tuning for this general class, and has a wide range of applications, including
robust regression and classification. We illustrate some of these applications
with numerical examples on synthetic and real data.


title: Higher-Dimensional general Jacobi identities I

abstract:
  It was shown by the author [International Journal of Theoretical Physics 36
(1997), 1099-1131] in synthetic differential geometry that what is called the
general Jacobi identity obtaining in microcubes underlies the Jacobi identity
of vector fields. It is well known in the theory of Lie algebras that a
plethora of higher-dimensional generalizations of the Jacobi identity hold,
though it is usually established not as a direct derivation from the axioms of
Lie algebras but by making an appeal to the so-called Poincar\'e-Birkhoff-Witt
theorem. The general Jacobi identity was rediscovered by Kirill Mackenzie in
the second decade of this century [Geometric Methods in Physics, 357-366,
Birkh\"auser/Springer 2013]. The principal objective in this paper is to
investigate a four-dimensional generalization of the general Jacobi identity in
detail. In a subsequent paper we will propose a uniform method for establishing
a bevy of higher-dimensional generalizations of the Jacobi identity under a
single umbrella.


title:
Planck intermediate results. LI. Features in the cosmic microwave
  background temperature power spectrum and shifts in cosmological parameters

abstract:
  The six parameters of the standard $\Lambda$CDM model have best-fit values
derived from the Planck temperature power spectrum that are shifted somewhat
from the best-fit values derived from WMAP data. These shifts are driven by
features in the Planck temperature power spectrum at angular scales that had
never before been measured to cosmic-variance level precision. We investigate
these shifts to determine whether they are within the range of expectation and
to understand their origin in the data. Taking our parameter set to be the
optical depth of the reionized intergalactic medium $\tau$, the baryon density
$\omega_{\rm b}$, the matter density $\omega_{\rm m}$, the angular size of the
sound horizon $\theta_*$, the spectral index of the primordial power spectrum,
$n_{\rm s}$, and $A_{\rm s}e^{-2\tau}$ (where $A_{\rm s}$ is the amplitude of
the primordial power spectrum), we examine the change in best-fit values
between a WMAP-like large angular-scale data set (with multipole moment
$\ell<800$ in the Planck temperature power spectrum) and an all angular-scale
data set ($\ell<2500$ Planck temperature power spectrum), each with a prior on
$\tau$ of $0.07\pm0.02$. We find that the shifts, in units of the 1$\sigma$
expected dispersion for each parameter, are $\{\Delta \tau, \Delta A_{\rm s}
e^{-2\tau}, \Delta n_{\rm s}, \Delta \omega_{\rm m}, \Delta \omega_{\rm b},
\Delta \theta_*\} = \{-1.7, -2.2, 1.2, -2.0, 1.1, 0.9\}$, with a $\chi^2$ value
of 8.0. We find that this $\chi^2$ value is exceeded in 15% of our simulated
data sets, and that a parameter deviates by more than 2.2$\sigma$ in 9% of
simulated data sets, meaning that the shifts are not unusually large. Comparing
$\ell<800$ instead to $\ell>800$, or splitting at a different multipole, yields
similar results. We examine the $\ell<800$ model residuals in the $\ell>800$
power spectrum data and find that the features there... [abridged]


title:
Measurement-based perturbation theory and differential equation
  parameter estimation with applications to satellite gravimetry

abstract:
  The numerical integration method has been routinely used to produce global
standard gravitational models from satellite tracking measurements of
CHAMP/GRACE types. It is implemented by solving the differential equations of
the partial derivatives of a satellite orbit with respect to the unknown
harmonic coefficients under the conditions of zero initial values. From the
mathematical point of view, satellite gravimetry from satellite tracking is the
problem of estimating unknown parameters in the Newton's nonlinear differential
equations from satellite tracking measurements. We prove that zero initial
values for the partial derivatives are incorrect mathematically and not
permitted physically. The numerical integration method, as currently
implemented and used in satellite gravimetry and statistics, is groundless. We
use three different methods to derive new local solutions to the Newton's
nonlinear governing differential equations of motion with a nominal reference
orbit. Bearing in mind that satellite orbits can now be tracked almost
continuously at unprecedented high accuracy, we propose the measurement-based
perturbation theory and derive global uniformly convergent solutions to the
Newton's nonlinear governing differential equations of motion. Since the
solutions are global uniformly convergent, they are able to extract smallest
possible gravitational signals from modern and future satellite tracking
measurements for global high-precision, high-resolution gravitational models.
By directly turning the nonlinear differential equations of satellite motion
into the nonlinear integral equations, we reformulate the links between
satellite tracking measurements and the global uniformly convergent solutions
to the Newton's governing differential equations as a condition adjustment
model with equality constraints.


title: Phenomenological MSSM in light of new 13 TeV LHC data

abstract:
  We present the first analysis of the p19MSSM with neutralino dark matter, in
light of 13 TeV LHC data with an integrated luminosity of ~14/fb. We recast
twelve experimental analyses performed by the ATLAS collaboration and derive
exclusion bounds on the parameter space of the model. We find that 25% of the
model points can be excluded at 95% C.L. by a combination of the implemented
searches. The spectrum allowed after the 13 TeV results are taken into account
presents stops heavier than at least 400 GeV, gluinos heavier than at least 790
GeV, and squarks of the first and second generation heavier than at least 440
GeV.


title:
Wireless transfer of power by a 35-GHz metamaterial split-ring resonator
  rectenna

abstract:
  Wireless transfer of power via high frequency microwave radiation using a
miniature split ring resonator rectenna is reported. RF power is converted into
DC power by integrating a rectification circuit with the split ring resonator.
The near-field behavior of the rectenna is investigated with microwave
radiation in the frequency range between 20-40 GHz with a maximum power level
of 17 dBm. The observed resonance peaks match those predicted by simulation.
Polarization studies show the expected maximum in signal when the electric
field is polarized along the edge of the split ring resonator with the gap and
minimum for perpendicular orientation. The efficiency of the rectenna is on the
order of 1% for a frequency of 37.2 GHz. By using a cascading array of 9 split
ring resonators the output power was increased by a factor of 20.


title:
Parameter estimates in binary black hole collisions using neural
  networks

abstract:
  We present an algorithm based on artificial neural networks (ANNs), that
estimates the mass ratio in a binary black hole collision out of given
Gravitational Wave (GW) strains. In this analysis, the ANN is trained with a
sample of GW signals generated with numerical simulations. The effectiveness of
the algorithm is evaluated with GWs generated also with simulations for given
mass ratios unknown to the ANN. We measure the accuracy of the algorithm in the
interpolation and extrapolation regimes. We present the results for noise free
signals and signals contaminated with Gaussian noise, in order to foresee the
dependence of the method accuracy in terms of the signal to noise ratio.


title: Regular subgroups of the affine group with no translations

abstract:
  Given a regular subgroup R of AGL_n(F), one can ask if R contains nontrivial
translations. A negative answer to this question was given by Liebeck, Praeger
and Saxl for AGL_2(p) (p a prime), AGL_3(p) (p odd) and for AGL_4(2). A
positive answer was given by Hegedus for AGL_n(p) when n >= 4 if p is odd and
for n=3 or n >= 5 if p=2. A first generalization to finite fields of Hegedus'
construction was recently obtained by Catino, Colazzo and Stefanelli. In this
paper we give examples of such subgroups in AGL_n(F) for any n >= 5 and any
field F. For n < 5 we provide necessary and sufficient conditions for their
existence, assuming R to be unipotent if char F=0.


title:
KIC 3749404: A heartbeat Star with Rapid Apsidal Advance Indicative of a
  Tertiary Component

abstract:
  Heartbeat stars are eccentric (e > 0.2) ellipsoidal variables whose light
curves resemble a cardiogram. We present the observations and corresponding
model of KIC 3749404, a highly eccentric (e = 0.66), short period (P = 20.3 d)
heartbeat star with tidally induced pulsations. A binary star model was created
using PHOEBE, which we modified to include tidally induced pulsations and
Doppler boosting. The morphology of the photometric periastron variation
(heartbeat) depends strongly on the eccentricity, inclination and argument of
periastron. We show that the inclusion of tidally induced pulsations in the
model significantly changes the parameter values, specifically the inclination
and those parameters dependent on it. Furthermore, we determine the rate of
apsidal advance by modelling the periastron variation at the beginning and end
of the 4-yr Kepler data set and dividing by the elapsed time. We compare the
model with the theoretical expectations for classical and general relativistic
apsidal motion and find the observed rate to be two orders of magnitude greater
than the theoretical rate. We find that the observed rate cannot be explained
by tidally induced pulsations alone and consequently hypothesise the presence
of a third body in the system.


title:
Measurements of the Atmospheric Electric Field through a Triangular
  Array and the Long-range Saharan Dust Electrification in Southern Portugal

abstract:
  Atmospheric electric field (AEF) measurements were carried out in three
different sites forming a triangular array in Southern Portugal. The campaign
was performed during the summer characterized by Saharan dust outbreaks; the
16th-17th July 2014 desert dust event is considered here. Evidence of
long-range dust electrification is attributed to the air-Earth electrical
current creating a positive space-charge inside of the dust layer. An increase
of ~23 V/m is observed in AEF on the day of the dust event corresponding to
space-charges of ~20-2 pCm-3 (charge layer thicknesses ~10-100 m). A reduction
of AEF is observed after the dust event.


title: Point-like bounding chains in open Gromov-Witten theory

abstract:
  We present a solution to the problem of defining genus zero open
Gromov-Witten invariants with boundary constraints for a Lagrangian submanifold
of arbitrary dimension. Previously, such invariants were known only in
dimensions $2$ and $3$ from the work of Welschinger. Our approach does not
require the Lagrangian to be fixed by an anti-symplectic involution, but can
use such an involution, if present, to obtain stronger results. Also,
non-trivial invariants are defined for broader classes of interior constraints
and Lagrangian submanifolds than previously possible even in the presence of an
anti-symplectic involution. The invariants of the present work specialize to
invariants of Welschinger, Fukaya, and Georgieva in many instances.
  The main obstacle to defining open Gromov-Witten invariants with boundary
constraints in arbitrary dimension is the bubbling of $J$-holomorphic disks.
Unlike in low dimensions or for interior constraints, disk bubbles do not
cancel in pairs by anti-symplectic involution symmetry. Rather, we use the
technique of bounding chains introduced in Fukaya-Oh-Ohta-Ono's work on
Lagrangian Floer theory to cancel disk bubbling. At the same time and
independently, gauge equivalence classes of bounding chains play the role of
boundary constraints, in place of the cohomology classes that usually serve as
constraints in Gromov-Witten theory. A crucial step in our construction is to
identify a canonical up to gauge equivalence family of "point-like" bounding
chains, which specialize in dimensions $2$ and $3$ to the point constraints
considered by Welschinger.


title: A Multi-Channel Setup to Study Fractures in Scintillators

abstract:
  To investigate fractoluminescence in scintillating crystals used for particle
detection, we have developed a multi-channel setup built around samples of
double-cleavage drilled compression (DCDC) geometry in a controllable
atmosphere. The setup allows the continuous digitization over hours of various
parameters, including the applied load, and the compressive strain of the
sample, as well as the acoustic emission. Emitted visible light is recorded
with nanosecond resolution, and crack propagation is monitored using infrared
lighting and camera. An example of application to Bi4Ge3O12 (BGO) is provided.


title: Composites of FeCl3 and TiO2 with Bismaleimide resins

abstract:
  Ferric Chloride-Bismaleimide (FeCl3-BMI) and Titania-Bismaleimide (TiO2-BMI)
composite were synthesized using PVA as a binder. The composite systems were
deposited on glass slide as a homogenous coating. XRD and FTIR studies of the
composite system showed its crystalline and structural configuration. A mixed
phase of TiO2 and BMI as well as short range crystallinity was observed. An
increase in crystallinity with temperature was also seen. The percentage of N-H
symmetric stretching was also found to increase with temperature.


title: Luminosity Limitations in Linear Colliders Based on Plasma Acceleration

abstract:
  Particle acceleration in plasma creates a possibility of exceptionally high
accelerating gradients and appears as a very attractive option for future
linear electron-positron and/or photon-photon colliders. These high
accelerating gradients were already demonstrated in a number of experiments.
However, a linear collider requires exceptionally high beam brightness which
still needs to be demonstrated. In this article we discuss major phenomena
which limit the beam brightness of accelerated beam and, consequently, the
collider luminosity.


title:
Identifying Stereotypes in the Online Perception of Physical
  Attractiveness

abstract:
  Stereotyping can be viewed as oversimplified ideas about social groups. They
can be positive, neutral or negative. The main goal of this paper is to
identify stereotypes for female physical attractiveness in images available in
the Web. We look at the search engines as possible sources of stereotypes. We
conducted experiments on Google and Bing by querying the search engines for
beautiful and ugly women. We then collect images and extract information of
faces. We propose a methodology and apply it to analyze photos gathered from
search engines to understand how race and age manifest in the observed
stereotypes and how they vary according to countries and regions. Our findings
demonstrate the existence of stereotypes for female physical attractiveness, in
particular negative stereotypes about black women and positive stereotypes
about white women in terms of beauty. We also found negative stereotypes
associated with older women in terms of physical attractiveness. Finally, we
have identified patterns of stereotypes that are common to groups of countries.


title:
Fej\'er-monotone hybrid steepest descent method for affinely constrained
  and composite convex minimization tasks

abstract:
  This paper introduces the Fej\'er-monotone hybrid steepest descent method
(FM-HSDM), a new member to the HSDM family of algorithms, for solving affinely
constrained minimization tasks in real Hilbert spaces, where convex smooth and
non-smooth losses compose the objective function. FM-HSDM offers sequences of
estimates which converge weakly and, under certain hypotheses, strongly to
solutions of the task at hand. Fixed-point theory, variational inequalities and
affine-nonexpansive mappings are utilized to devise a scheme that accommodates
affine constraints in a more versatile way than state-of-the-art primal-dual
techniques and the alternating direction method of multipliers do. Recursions
can be tuned to score low computational footprints, well-suited for large-scale
optimization tasks, without compromising convergence guarantees. In contrast to
its HSDM's precursors, FM-HSDM enjoys Fej\'er monotonicity, the step-size
parameter stays constant across iterations to promote convergence speed-ups of
the sequence of estimates to a minimizer, while only Lipschitzian continuity,
and not strong monotonicity, of the derivative of the smooth-loss function is
needed to ensure convergence. Results on the rate of convergence to an optimal
point are also presented.


title:
WKB propagators in position and momentum space for a linear potential
  with a "ceiling" boundary

abstract:
  As a model for the semiclassical analysis of quantum-mechanical systems with
both potentials and boundary conditions, we construct the WKB propagator for a
linear potential sloping away from an impenetrable boundary. First, we find all
classical paths from point $y$ to point $x$ in time $t$ and calculate the
corresponding action and amplitude functions. A large part of space-time turns
out to be classically inaccessible, and the boundary of this region is a
caustic of an unusual type, where the amplitude vanishes instead of diverging.
We show that this curve is the limit of caustics in the usual sense when the
reflecting boundary is approximated by steeply rising smooth potentials. Then,
to improve the WKB approximation we construct the propagator for initial data
in momentum space; this requires classifying the interesting variety of
classical paths with initial momentum $p$ arriving at $x$ after time $t$. The
two approximate propagators are compared by applying them to Gaussian initial
packets by numerical integration; the results show physically expected
behavior, with advantages to the momentum-based propagator in the classically
forbidden regime (large $t$).


title:
The design and development of a high-resolution visible-to-near-UV
  telescope for balloon-borne astronomy: SuperBIT

abstract:
  Balloon-borne astronomy is unique in that it allows for a level of image
stability, resolution, and optical backgrounds that are comparable to
space-borne systems due to greatly reduced atmospheric interference, but at a
fraction of the cost and over a significantly reduced development time-scale.
Instruments operating within visible-to-near-UV bands ($300$ - $900$ um) can
achieve a theoretical diffraction limited resolution of $0.01"$ from the
stratosphere ($35$ - $40$ km altitude) without the need for extensive adaptive
optical systems required by ground-based systems. The {\it Superpressure
Balloon-borne Imaging Telescope} ("SuperBIT") is a wide-field imager designed
to achieve 0.02$"$ stability over a 0.5$^\circ$ field-of-view, for deep single
exposures of up to 5 minutes. SuperBIT is thus well-suited for many
astronomical observations, from solar or extrasolar planetary observations, to
resolved stellar populations and distant galaxies (whether to study their
morphology, evolution, or gravitational lensing by foreground mass). We report
SuperBIT's design and implementation, emphasizing its two-stage real-time
stabilization: telescope stability to $1$ - $2"$ at the telescope level (a goal
surpassed during a test flight in September 2015) and image stability down to
$0.02"$ via an actuated tip-tilt mirror in the optical path (to be tested
during a flight in 2016). The project is progressing toward a fully
operational, three month flight from New Zealand by 2018


title: Each n-by-n matrix with n>1 is a sum of 5 coninvolutory matrices

abstract:
  An $n\times n$ complex matrix $A$ is called coninvolutory if $\bar AA=I_n$
and skew-coninvolutory if $\bar AA=-I_n$ (which implies that $n$ is even). We
prove that each matrix of size $n\times n$ with $n>1$ is a sum of 5
coninvolutory matrices and each matrix of size $2m\times 2m$ is a sum of 5
skew-coninvolutory matrices.
  We also prove that each square complex matrix is a sum of a coninvolutory
matrix and a condiagonalizable matrix. A matrix $M$ is called condiagonalizable
if $M=\bar S^{-1}DS$ in which $S$ is nonsingular and $D$ is diagonal.


title: Star Products that can not be induced by Drinfel'd Twists

abstract:
  This is the final version of my master thesis. I prove that there are no
twist star products on the 2-sphere and on the higher genus pretzel surfaces
deforming a symplectic structure. One of the key arguments is that a connected
compact symplectic manifold endowed with a twist star product has to be a
homogeneous space. Furthermore, there is a non-degenerate r-matrix on a Lie
algebra whose Lie group is acting transitively and effectively on the manifold
in this case. I recap the theory of homogeneous spaces, in particular the
classification of transitive effective actions on the 2-sphere, and discuss the
notion of r-matrices and Drinfel'd twists. Some results of this thesis are
available as a preprint with Pierre Bieliavsky, Chiara Esposito and Stefan
Waldmann on arxiv.org under the title "Obstructions for Twist Star Products".