title:
Extremely metal-poor galaxy DDO 68: the LBV, H-alpha shells and the most
  luminous stars

abstract:
  The paper presents new results of the ongoing study of the unusual
Lynx-Cancer void galaxy DDO 68 with record-low-metallicity regions (12+log(O/H)
~7.14) of the current star formation (SF). They include: a) a new spectrum and
photometry with the 6-m SAO RAS telescope (BTA) for the Luminous Blue Variable
(LBV = DDO68-V1). Photometric data sets are complemented with those based on
the Sloan Digital Sky Survey (SDSS) and the Hubble Space Telescope (HST)
archive images; b) the analysis of the DDO~68 supergiant shell (SGS) and the
prominent smaller H-alpha arcs/shells visible at the HST image coupled with
kinematics maps in H-alpha obtained with the Fabry-Perot interferometer (FPI)
at the BTA; c) the list of identified at the HST images of about 50 most
luminous stars (-9.1 < M_V < -6.0 mag) related to star-forming regions with the
known extremely low O/H. This is intended to pave the path for the actual
science with the next generation of giant telescopes. We confirm the earlier
hints on significant variations of the LBV optical light deriving its amplitude
of dV > 3.7~mag for the first time. New data suggest that in 2008--2010 the LBV
reached M_V = --10.5 and probably underwent a giant eruption. We argue that the
structure of star-forming complexes along the SGS (`Northern Ring') perimeter
provides evidence for the sequential induced SF episodes caused by the shell
gas instabilities and gravitational collapse. The variability of some DDO~68
luminous extremely metal-poor stars can be monitored with medium-size
telescopes at sites with superb seeing.


title:
Degeneration of endomorphisms of the complex projective space in the
  hybrid space

abstract:
  We consider a meromorphic family of endomorphisms of degree at least 2 of a
complex projective space that is parameterized by the unit disk.We prove that
the measure of maximal entropy of these endomorphisms converges to the
equilibrium measure of the associated non-Archimedean dynamical system when the
system degenerates. The convergence holdsin the hybrid space constructed by
Berkovich and further studied by Boucksom and Jonsson. We also infer from our
analysis an estimate for the blow-up of the Lyapunov exponent near a pole in
one-dimensional families of endomorphisms.


title:
Johnson-Segalman -- Saint-Venant equations for viscoelastic shallow
  flows in the elastic limit

abstract:
  The shallow-water equations of Saint-Venant, often used to model the
long-wave dynamics of free-surface flows driven by inertia and hydrostatic
pressure, can be generalized to account for the elongational rheology of
non-Newtonian fluids too. We consider here the $4 \times 4$ shallow-water
equations generalized to viscoelastic fluids using the Johnson-Segalman model
in the elastic limit (i.e. at infinitely-large Deborah number, when source
terms vanish). The system of nonlinear first-order equations is hyperbolic when
the slip parameter is small $\zeta \le 1/2$ ($\zeta$ = 1 is the corotational
case and $\zeta = 0$ the upper-convected Maxwell case). Moreover, it is
naturally endowed with a mathematical entropy (a physical free-energy). When
$\zeta \le 1/2$ and for any initial data excluding vacuum, we construct here,
when elasticity $G > 0$ is non-zero, the unique solution to the Riemann problem
under Lax admissibility conditions. The standard Saint-Venant case is recovered
when $G \to 0$ for small data.


title: A Multimodal Approach to Estimating Vigilance Using EEG and Forehead EOG

abstract:
  Objective. Covert aspects of ongoing user mental states provide key context
information for user-aware human computer interactions. In this paper, we focus
on the problem of estimating the vigilance of users using EEG and EOG signals.
Approach. To improve the feasibility and wearability of vigilance estimation
devices for real-world applications, we adopt a novel electrode placement for
forehead EOG and extract various eye movement features, which contain the
principal information of traditional EOG. We explore the effects of EEG from
different brain areas and combine EEG and forehead EOG to leverage their
complementary characteristics for vigilance estimation. Considering that the
vigilance of users is a dynamic changing process because the intrinsic mental
states of users involve temporal evolution, we introduce continuous conditional
neural field and continuous conditional random field models to capture dynamic
temporal dependency. Main results. We propose a multimodal approach to
estimating vigilance by combining EEG and forehead EOG and incorporating the
temporal dependency of vigilance into model training. The experimental results
demonstrate that modality fusion can improve the performance compared with a
single modality, EOG and EEG contain complementary information for vigilance
estimation, and the temporal dependency-based models can enhance the
performance of vigilance estimation. From the experimental results, we observe
that theta and alpha frequency activities are increased, while gamma frequency
activities are decreased in drowsy states in contrast to awake states.
Significance. The forehead setup allows for the simultaneous collection of EEG
and EOG and achieves comparative performance using only four shared electrodes
in comparison with the temporal and posterior sites.


title:
Modular forms, Schwarzian conditions, and symmetries of differential
  equations in physics

abstract:
  We give examples of infinite order rational transformations that leave linear
differential equations covariant. These examples are non-trivial yet simple
enough illustrations of exact representations of the renormalization group. We
first illustrate covariance properties on order-two linear differential
operators associated with identities relating the same $_2F_1$ hypergeometric
function with different rational pullbacks. We provide two new and more general
results of the previous covariance by rational functions: a new Heun function
example and a higher genus $_2F_1$ hypergeometric function example. We then
focus on identities relating the same hypergeometric function with two
different algebraic pullback transformations: such remarkable identities
correspond to modular forms, the algebraic transformations being solution of
another differentially algebraic Schwarzian equation that emerged in a paper by
Casale. Further, we show that the first differentially algebraic equation can
be seen as a subcase of the last Schwarzian differential condition, the
restriction corresponding to a factorization condition of some associated
order-two linear differential operator. Finally, we also explore
generalizations of these results, for instance, to $_3F_2$, hypergeometric
functions, and show that one just reduces to the previous $_2F_1$ cases through
a Clausen identity.
  In a $_2F_1$ hypergeometric framework the Schwarzian condition encapsulates
all the modular forms and modular equations of the theory of elliptic curves,
but these two conditions are actually richer than elliptic curves or $_2F_1$
hypergeometric functions, as can be seen on the Heun and higher genus example.
  This work is a strong incentive to develop more differentially algebraic
symmetry analysis in physics.


title: A Command-line Cross-matching tool for modern astrophysical pipelines

abstract:
  The emerging need for efficient, reliable and scalable astronomical catalog
cross-matching is becoming more pressing in the current data-driven science
era, where the size of data has rapidly increased up to the Petabyte scale. C3
(Command-line Catalogue Cross-matching) is a multi-platform tool designed to
efficiently cross-match massive catalogues from modern astronomical surveys,
ensuring high-performance capabilities through the use of a multi-core parallel
processing paradigm. The tool has been conceived to be executed as a
stand-alone command-line process or integrated within any generic data
reduction/analysis pipeline, providing the maximum flexibility to the end user,
in terms of parameter configuration, coordinates and cross-matching types. In
this work we present the architecture and the features of the tool. Moreover,
since the modular design of the tool enables an easy customization to specific
use cases and requirements, we present also an example of a customized C3
version designed and used in the FP7 project ViaLactea, dedicated to
cross-correlate Hi-GAL clumps with multi-band compact sources.


title:
Nuclear fragmentation and charge-exchange reactions induced by pions in
  the $\Delta$-resonance region

abstract:
  Dynamics of the nuclear fragmentations and the charge exchange reactions in
pion-nucleus collisions near the $\Delta$(1232) resonance energies has been
investigated within the Lanzhou quantum molecular dynamics (LQMD) transport
model. An isospin, momentum and density-dependent pion-nucleon potential is
implemented in the model, which influences the pion dynamics, in particular the
kinetic energy spectra, but weakly impacts the fragmentation mechanism. The
absorption process in pion-nucleon collisions to form the $\Delta$(1232)
resonance dominates the heating mechanism of target nucleus. The excitation
energy transferred to the target nucleus increases with the pion kinetic energy
and is similar for both $\pi^{-}$ and $\pi^{+}$ induced reactions. The
magnitude of fragmentation of target nucleus weakly depends on the pion energy.
The isospin ratio in the pion double charge exchange is influenced by the
isospin ingredient of target nucleus.


title: Percolation on random graphs with a fixed degree sequence

abstract:
  We consider bond percolation on random graphs with given degrees and bounded
average degree. In particular, we consider the order of the largest component
after the random deletion of the edges of such a random graph. We give a rough
characterisation of those degree distributions for which bond percolation with
high probability leaves a component of linear order, known usually as a giant
component. We show that essentially the critical condition has to do with the
tail of the degree distribution. Our proof makes use of recent technique
introduced by Joos et al. [FOCS 2016, pp. 695--703], which is based on the
switching method and avoids the use of the classic configuration model as well
as the hypothesis of having a limiting object. Thus our results hold for sparse
degree sequences without the usual restrictions that accompany the
configuration model.


title: Finite-Volume QED Corrections to Decay Amplitudes in Lattice QCD

abstract:
  We demonstrate that the leading and next-to-leading finite-volume effects in
the evaluation of leptonic decay widths of pseudoscalar mesons at $O(\alpha)$
are universal, i.e. they are independent of the structure of the meson. This is
analogous to a similar result for the spectrum but with some fundamental
differences, most notably the presence of infrared divergences in decay
amplitudes. The leading non-universal, structure-dependent terms are of
$O(1/L^2)$ (compared to the $O(1/L^3)$ leading non-universal corrections in the
spectrum). We calculate the universal finite-volume effects, which requires an
extension of previously developed techniques to include a dependence on an
external three-momentum (in our case, the momentum of the final state lepton).
The result can be included in the strategy proposed in
Ref.\,\cite{Carrasco:2015xwa} for using lattice simulations to compute the
decay widths at $O(\alpha)$, with the remaining finite-volume effects starting
at order $O(1/L^2)$. The methods developed in this paper can be generalised to
other decay processes, most notably to semileptonic decays, and hence open the
possibility of a new era in precision flavour physics.


title: On solution-free sets of integers II

abstract:
  Given a linear equation $\mathcal{L}$, a set $A \subseteq [n]$ is
$\mathcal{L}$-free if $A$ does not contain any `non-trivial' solutions to
$\mathcal{L}$. We determine the precise size of the largest $\mathcal{L}$-free
subset of $[n]$ for several general classes of linear equations $\mathcal{L}$
of the form $px+qy=rz$ for fixed $p,q,r \in \mathbb N$ where $p \geq q \geq r$.
Further, for all such linear equations $\mathcal{L}$, we give an upper bound on
the number of maximal $\mathcal{L}$-free subsets of $[n]$. In the case when
$p=q\geq 2$ and $r=1$ this bound is exact up to an error term in the exponent.
  We make use of container and removal lemmas of Green to prove this result.
Our results also extend to various linear equations with more than three
variables.


title: An Analysis of Tournament Structure

abstract:
  This paper explores a novel way for analyzing the tournament structures to
find a best suitable one for the tournament under consideration. It concerns
about three aspects such as tournament conducting cost, competitiveness
development and ranking precision. It then proposes a new method using progress
tree to detect potential throwaway matches. The analysis performed using the
proposed method reveals the strengths and weaknesses of tournament structures.
As a conclusion, single elimination is best if we want to qualify one winner
only, all matches conducted are exciting in term of competitiveness. Double
elimination with proper seeding system is a better choice if we want to qualify
more winners. A reasonable number of extra matches need to be conducted in
exchange of being able to qualify top four winners. Round-robin gives reliable
ranking precision for all participants. However, its conduction cost is very
high, and it fails to maintain competitiveness development.


title:
Theoretical photon origin, a didactic introduction to the wave particle
  duality

abstract:
  In modern physics courses the idea of photon has been teaching through from
the einsteinian formulation based on the photoelectric effect. Einstein's
photon concept allow the quantization of the electromagnetic field, but does
not dwell on the idea of photon as particle. The objective of this paper was to
demonstrate that the photon has its origin essentially in the special
relativity, the electromagnetic theory and in the symmetry between the
Lorentz's transformations associated flat monochromatic electromagnetic waves
and particles with zero rest mass. This approach allows to understand the
wave-particle duality of photon and allows to propose an alternative teaching
focused on this duality to develop the course of modern physics.


title: Plane symmetric cosmological models

abstract:
  In the present work, we execute the Lie symmetry analysis on the
Einstein-Maxwell field equations in the plane symmetric spacetime. Under the
background of the plane symmetric space-time we compute the Lie point
symmetries, perform the similarity reductions and obtain exact solutions in
connection to the evolutionary scenario of the universe. The special feature of
the study is that it deals with the electromagnetic energy of the inhomogeneous
universe through the non-vanishing component of electromagnetic field tensor
$F_{12}$ and assumes that the free gravitational field is of Petrov type-II
non-degenerate. We have found that the electromagnetic field tensor is positive
and increasing function of time. To validate the solution set, we examine with
detailed discussions several physical as well as geometrical features of a
specific sub-case of the model.


title:
Statistical and computational intelligence approach to analytic
  continuation in Quantum Monte Carlo

abstract:
  The term analytic continuation emerges in many branches of Mathematics,
Physics, and, more generally, applied Science. Generally speaking, in many
situations, given some amount of information that could arise from experimental
or numerical measurements, one is interested in extending the domain of such
information, to infer the values of some variables which are central for the
study of a given problem. For example, focusing on Condensed Matter Physics,
state-of-the-art methodologies to study strongly correlated quantum physical
systems are able to yield accurate estimations of dynamical correlations in
imaginary time. Those functions have to be extended to the whole complex plane,
via analytic continuation, in order to infer real-time properties of those
physical systems. In this Review, we will present the Genetic Inversion via
Falsification of Theories method, which allowed us to compute dynamical
properties of strongly interacting quantum many--body systems with very high
accuracy. Even though the method arose in the realm of Condensed Matter
Physics, it provides a very general framework to face analytic continuation
problems that could emerge in several areas of applied Science. Here we provide
a pedagogical review that elucidates the approach we have developed.


title:
The action of Volterra integral operators with highly singular kernels
  on H\"older continuous, Lebesgue and Sobolev functions

abstract:
  For kernels $\nu$ which are positive and integrable we show that the operator
$g\mapsto J_\nu g=\int_0^x \nu(x-s)g(s)ds$ on a finite time interval enjoys a
regularizing effect when applied to H\"older continuous and Lebesgue functions
and a "contractive" effect when applied to Sobolev functions. For H\"older
continuous functions, we establish that the improvement of the regularity of
the modulus of continuity is given by the integral of the kernel, namely by the
factor $N(x)=\int_0^x \nu(s)ds$. For functions in Lebesgue spaces, we prove
that an improvement always exists, and it can be expressed in terms of Orlicz
integrability. Finally, for functions in Sobolev spaces, we show that the
operator $J_\nu$ "shrinks" the norm of the argument by a factor that, as in the
H\"older case, depends on the function $N$ (whereas no regularization result
can be obtained). These results can be applied, for instance, to Abel kernels
and to the Volterra function $\mathcal{I}(x) = \mu(x,0,-1) =
\int_{0}^{\infty}x^{s-1}/\Gamma(s)\,ds$, the latter being relevant for instance
in the analysis of the Schr\"odinger equation with concentrated nonlinearities
in $\mathbb{R}^{2}$.


title: Leptogenesis: Improving predictions for experimental searches

abstract:
  Heavy right handed neutrinos could not only explain the observed neutrino
masses via the seesaw mechanism, but also generate the baryon asymmetry of the
universe via leptogenesis due to their CP-violating interactions in the early
universe. We review recent progress in the theoretical description of this
nonequilibrium process. Improved calculations are particularly important for a
comparison with experimental data in testable scenarios with Majorana masses
below the TeV scale, in which the heavy neutrinos can be found at the LHC, in
the NA62 experiment, at T2K or in future experiments, including SHiP, DUNE and
experiments at the FCC, ILC or CEPC. In addition, the relevant source of
CP-violation may be experimentally accessible, and the heavy neutrinos can give
a sizable contribution to neutrinoless double $\beta$ decay. In these low scale
leptogenesis scenarios, the matter-antimatter asymmetry is generated at
temperatures when the heavy neutrinos are relativistic, and thermal corrections
to the transport equations in the early universe are large.


title:
Evaluation at the Remote Site for Ultra-stable Radio Frequency
  Dissemination via Fiber Links

abstract:
  We demonstrate a method which can directly evaluate the radio frequency
transfer quality via fiber links at the remote site. Coherent signals are first
transferred to the same remote site via two stabilized fiber links. The two
signals at the remote site are compared with each other. The relative phase
difference can represent transfer stability loss. This evaluation method at the
remote site has been compared with the traditional one with which the signal is
evaluated at the local site. The two results match perfectly. It indicates that
the method is available to evaluate the transfer performance of radio frequency
(RF) dissemination in such applications as antenna array systems.


title: Entanglement in non-unitary quantum critical spin chains

abstract:
  Entanglement entropy has proven invaluable to our understanding of quantum
criticality. It is natural to try to extend the concept to non-unitary quantum
mechanics, which has seen growing interest from areas as diverse as open
quantum systems, non-interacting electronic disordered systems, or non-unitary
conformal field theory (CFT). We propose and investigate such an extension
here, by focussing on the case of one-dimensional quantum group symmetric or
supergroup symmetric spin chains. We show that the consideration of left and
right eigenstates combined with appropriate definitions of the trace leads to a
natural definition of R\'enyi entropies in a large variety of models. We
interpret this definition geometrically in terms of related loop models and
calculate the corresponding scaling in the conformal case. This allows us to
distinguish the role of the central charge and effective central charge in
rational minimal models of CFT, and to define an effective central charge in
other, less well understood cases. The example of the $sl(2|1)$ alternating
spin chain for percolation is discussed in detail.


title: The little-studied cluster Berkeley 90. III. Cluster parameters

abstract:
  The open cluster Berkeley 90 is the home to one of the most massive binary
systems in the Galaxy, LS III +46$^{\circ}$11, formed by two identical, very
massive stars (O3.5 If* + O3.5 If*), and a second early-O system (LS III
+46$^{\circ}$12 with an O4.5 IV((f)) component at least). Stars with spectral
types earlier than O4 are very scarce in the Milky Way, with no more than 20
examples. The formation of such massive stars is still an open question today,
and thus the study of the environments where the most massive stars are found
can shed some light on this topic. To this aim, we determine the properties and
characterize the population of Berkeley 90 using optical, near-infrared and
WISE photometry and optical spectroscopy. This is the first determination of
these parameters with accuracy. We find a distance of $3.5^{+0.5}_{-0.5}$ kpc
and a maximum age of 3 Ma. The cluster mass is around $1000$ $M_{\odot}$
(perhaps reaching $1500$ $M_{\odot}$ if the surrounding population is added),
and we do not detect candidate runaway stars in the area. There is a second
population of young stars to the Southeast of the cluster that may have formed
at the same time or slightly later, with some evidence for low-activity ongoing
star formation.


title:
Galaxy cluster outskirts from the thermal SZ and non-thermal synchrotron
  link

abstract:
  Galaxy cluster merger shocks are the main agent for the thermalization of the
intracluster medium and the energization of cosmic ray particles in it. Shock
propagation changes the state of the tenuous intracluster plasma, and the
corresponding signal variations are measurable with the current generation of
X-ray and Sunyaev-Zel'dovich (SZ) effect instruments. Additionally, non-thermal
electrons (re-)energized by the shocks sometimes give rise to extended and
luminous synchrotron sources known as radio relics, which are prominent
indicators of shocks propagating roughly in the plane of the sky. In this short
review, we discuss how the joint modeling of the non-thermal and thermal signal
variations across radio relic shock fronts is helping to advance our knowledge
of the gas thermodynamical properties and magnetic field strengths in the
cluster outskirts. We describe the first use of the SZ effect to measure the
Mach numbers of relic shocks, for both the nearest (Coma) and the farthest (El
Gordo) clusters with known radio relics.


title:
Electronic Structure and Optical Properties of Monolayer $ReS_2$ with
  Defect Controlled by Strain Engineering

abstract:
  By using first-principles calculations, we investigated the monolayer $ReS_2$
with vacancies under strain engineering, specifically focusing on its energy of
formation, band gap, electron density of states, effective mass and optical
properties. The calculated results disclose that S4 defect is more likely to
form than other kinds of vacancies. Asymmetric deformation induced by strain
makes its band structure transformation from direct band gap to indirect band
gap. The analysis of the partial density of states indicates that the Re-d,
Re-p and S-d orbitals are the major components of the defect states, being
different from $MoS_2$, the defect states locate both above and below the Fermi
level. Moreover, the effective mass was sensitive and anisotropic under the
external strain. The reflection spectrum can be greatly tuned by the external
strains, which indicates that the ReS2 monolayer has promising applications in
nanoscale strain sensor and conductance-switch FETs.


title: Can Agent-Based Models Probe Market Microstructure?

abstract:
  We extend prior evidence that naively using intraday agent-based models that
involve realistic order-matching processes for modeling continuous-time double
auction markets seems to fail to be able to provide a robust link between data
and many model parameters, even when these models are able to reproduce a
number of well-known stylized facts of return time series. We demonstrate that
while the parameters of intraday agent-based models rooted in market
microstructure can be meaningfully calibrated, those exclusively related to
agent behaviors and incentives remain problematic. This could simply be a
failure of the calibration techniques used but we argue that the observed
parameter degeneracies are most likely a consequence of the realistic matching
processes employed in these models. This suggests that alternative approaches
to linking data, phenomenology and market structure may be necessary and that
it is conceivable that one could construct a useful model that does not
directly depend on the nuances of agent behaviors, even when it is known that
the real agents engage in complex behaviors.


title: A top-squark hunter's guide

abstract:
  In supersymmetric models with radiatively-driven naturalness and light
higgsinos, the top squarks may lie in the 0.5- 3TeV range and thus only a
fraction of natural parameter space is accessible to LHC searches. We outline
the range of top squark and lightest SUSY particle masses preferred by
electroweak naturalness in the standard parameter space plane. We note that the
branching fraction for b-> s\gamma decay favors top squarks much heavier than
500 GeV. Such a range of top-squark mass values is in contrast to previous
expectations where m(stop)<500 GeV had been considered natural. In radiative
natural SUSY, top squarks decay roughly equally via t1-> bW1 and Z_{1,2} where
W1 and Z_{1,2} are higgsino-like electroweak-inos. Thus, top squark pair
production should yield all of t\bar{t}+\eslt, t\bar{b}+\eslt, b\bar{t}+\eslt
and b\bar{b}+\eslt signatures at comparable rates. We propose that future LHC
top squark searches take place within a semi-simplified model which corresponds
more closely to expectations from theory.


title: Person Re-Identification by Unsupervised Video Matching

abstract:
  Most existing person re-identification (ReID) methods rely only on the
spatial appearance information from either one or multiple person images,
whilst ignore the space-time cues readily available in video or image-sequence
data. Moreover, they often assume the availability of exhaustively labelled
cross-view pairwise data for every camera pair, making them non-scalable to
ReID applications in real-world large scale camera networks. In this work, we
introduce a novel video based person ReID method capable of accurately matching
people across views from arbitrary unaligned image-sequences without any
labelled pairwise data. Specifically, we introduce a new space-time person
representation by encoding multiple granularities of spatio-temporal dynamics
in form of time series. Moreover, a Time Shift Dynamic Time Warping (TS-DTW)
model is derived for performing automatically alignment whilst achieving data
selection and matching between inherently inaccurate and incomplete sequences
in a unified way. We further extend the TS-DTW model for accommodating multiple
feature-sequences of an image-sequence in order to fuse information from
different descriptions. Crucially, this model does not require pairwise
labelled training data (i.e. unsupervised) therefore readily scalable to large
scale camera networks of arbitrary camera pairs without the need for exhaustive
data annotation for every camera pair. We show the effectiveness and advantages
of the proposed method by extensive comparisons with related state-of-the-art
approaches using two benchmarking ReID datasets, PRID2011 and iLIDS-VID.


title: Miniature loops in the solar corona

abstract:
  Magnetic loops filled with hot plasma are the main building blocks of the
solar corona. Usually they have lengths of the order of the barometric scale
height in the corona that is 50 Mm. Previously it has been suggested that
miniature versions of hot loops exist. These would have lengths of only 1 Mm
barely protruding from the chromosphere and spanning across just one granule in
the photosphere. Such short loops are well established at transition region
temperatures (0.1 MK), and we investigate if such miniature loops also exist at
coronal temperatures (>1 MK). We used extreme UV imaging (EUV) observations
from the High-resolution Coronal Imager (Hi-C) at an unprecedented spatial
resolution of 0.3" to 0.4". Together with EUV imaging and magnetogram data from
the Solar Dynamics Observatory (SDO) and X-Ray Telescope (XRT) data from Hinode
we investigated the spatial, temporal and thermal evolution of small loop-like
structures in the solar corona above a plage region close to an active region
and compared this to a moss area within the active region. We find that the
size, motion and temporal evolution of the loop-like features are consistent
with photospheric motions, suggesting a close connection to the photospheric
magnetic field. Aligned magnetograms show that one of their endpoints is rooted
at a magnetic concentration. Their thermal structure, as revealed together with
the X-ray observations, shows significant differences to moss-like features.
Considering different scenarios, these features are most probably miniature
versions of hot loops rooted at magnetic concentrations at opposite sides of a
granule in small emerging magnetic loops (or flux tubes).


title:
Reliability of k-out-of-n Data Storage System with Deterministic
  Parallel and Serial Repair

abstract:
  In this paper, we find the Laplace Stieltjes transform of the probability of
data loss for the k-out-of-n distributed storage system with deterministic
repair times. We consider two repair models, namely the serial and parallel
repair. We show that for failure rate much lower than the repair rate, mean
time of data loss for the two models is the same unlike the case for
exponential repair models.


title: Higgs bundles over P^1 and quiver representations

abstract:
  In this note we prove a new explicit formula for the invariants of moduli
spaces of twisted Higgs bundles over P^1 and we relate these invariants to the
invariants of moduli spaces of representations of some infinite symmetric
quiver. The formula can be easily implemented for computations and it is in
agreement with the existing conjectures for the invariants of twisted Higgs
bundles over curves. Results of this note were presented in Oberwolfach in May
2014.


title: Non-Abelian Majorana modes protected by an emergent second Chern number

abstract:
  The search for topological superconductors and non-Abelian Majorana modes
ranks among the most fascinating topics in condensed matter physics. There now
exist several fundamental superconducting phases which host symmetry protected
or chiral Majorana modes. The latter, namely the chiral Majorana modes are
protected by Chern numbers in even dimensions. Here we propose to observe novel
chiral Majorana modes by realizing Fulde-Ferrell-Larkin-Ovchinnikov state, i.e.
the pairing density wave (PDW) phase in a Weyl semimetal which breaks
time-reversal symmetry. Without symmetry protection, the 3D gapped PDW phase is
topologically trivial. However, a vortex line generated in such phase can host
chiral Majorana modes, which are shown to be protected by an emergent second
Chern number of a synthetic 4D space generalized from the PDW phase. We further
show that these chiral modes in the vortex rings obey 3D non-Abelian
loop-braiding statistics, which can be applied to topological quantum
computation.


title: Local temperatures and local terms in modular Hamiltonians

abstract:
  We show there are analogues to the Unruh temperature that can be defined for
any quantum field theory and region of the space. These local temperatures are
defined using relative entropy with localized excitations. We show important
restrictions arise from relative entropy inequalities and causal propagation
between Cauchy surfaces. These suggest a large amount of universality for local
temperatures, specially the ones affecting null directions. For regions with
any number of intervals in two space-time dimensions the local temperatures
might arise from a term in the modular Hamiltonian proportional to the stress
tensor. We argue this term might be universal, with a coefficient that is the
same for any theory, and check analytically and numerically this is the case
for free massive scalar and Dirac fields. In dimensions $d\ge 3$ the local
terms in the modular Hamiltonian producing these local temperatures cannot be
formed exclusively from the stress tensor. For a free scalar field we classify
the structure of the local terms.


title: Testing CP-Violation in the Scalar Sector at Future $e^+e^-$ Colliders

abstract:
  We propose a {\em model-independent} method to test CP-violation in the
scalar sector through measuring the inclusive cross sections of
$e^+e^-\rightarrow Zh_1,Zh_2,h_1h_2$ processes with the recoil mass technique,
where $h_1, h_2$ stand for the 125 GeV standard model (SM) like Higgs boson and
a new lighter scalar respectively. This method effectively measures a quantity
$K$ proportional to the product of the three couplings of $h_1ZZ,h_2ZZ,h_1h_2Z$
vertices. The value of $K$ encodes a part of information about CP-violation in
the scalar sector. We simulate the signal and backgrounds for the processes
mentioned above with $m_{2}=40\textrm{GeV}$ at the Circular Electron-Positron
Collider (CEPC) with the integrated luminosity $5\textrm{ab}^{-1}$. We find
that the discovery of both $Zh_2$ and $h_1h_2$ processes at $5\sigma$ level
will indicate an $\mathcal{O}(10^{-2})$ $K$ value which can be measured to
$16\%$ precision. The method is applied to the weakly-coupled Lee model in
which CP-violation can be tested either before or after utilizing a "$p_T$
balance" cut (see \autoref{simu} for the definition). Lastly we point out that
$K\neq 0$ is a sufficient but not a necessary condition for the existence of
CP-violation in the scalar sector, namely $K = 0$ does not imply CP
conservation in the scalar sector.


title:
Diagonalizing transfer matrices and matrix product operators: a medley
  of exact and computational methods

abstract:
  Transfer matrices and matrix product operators play an ubiquitous role in the
field of many body physics. This paper gives an ideosyncratic overview of
applications, exact results and computational aspects of diagonalizing transfer
matrices and matrix product operators. The results in this paper are a mixture
of classic results, presented from the point of view of tensor networks, and of
new results. Topics discussed are exact solutions of transfer matrices in
equilibrium and non-equilibrium statistical physics, tensor network states,
matrix product operator algebras, and numerical matrix product state methods
for finding extremal eigenvectors of matrix product operators.

categories: cond-mat.str-el cond-mat.stat-mech math-ph math.MP quant-ph


title:
Dissecting the End-to-end Latency of Interactive Mobile Video
  Applications

abstract:
  In this paper we measure the step-wise latency in the pipeline of three kinds
of interactive mobile video applications that are rapidly gaining popularity,
namely Remote Graphics Rendering (RGR) of which we focus on mobile cloud
gaming, Mobile Augmented Reality (MAR), and Mobile Virtual Reality (MVR). The
applications differ from each other by the way in which the user interacts with
the application, i.e., video I/O and user controls, but they all share in
common the fact that their user experience is highly sensitive to end-to-end
latency. Long latency between a user control event and display update renders
the application unusable. Hence, understanding the nature and origins of
latency of these applications is of paramount importance. We show through
extensive measurements that control input and display buffering have a
substantial effect on the overall delay. Our results shed light on the latency
bottlenecks and the maturity of technology for seamless user experience with
these applications.


title:
Random and quasi-coherent aspects in particle motion and their effects
  on transport and turbulence evolution

abstract:
  The quasi-coherent effects in two-dimensional incompressible turbulence are
analyzed starting from the test particle trajectories. They can acquire
coherent aspects when the stochastic potential has slow time variation and the
motion is not strongly perturbed. The trajectories are, in these conditions,
random sequences of large jumps and trapping or eddying events. Trapping
determines quasi-coherent trajectory structures, which have a micro-confinement
effect that is reflected in the transport coefficients. They determine
non-Gaussian statistics and flows associated to an average velocity. Trajectory
structures also influence the test modes on turbulent plasmas. Nonlinear
damping and generation of zonal flow modes is found in drift turbulence in
uniform magnetic field. The coupling of test particle and test mode studies
permitted to evaluate the self-consistent evolution of the drift turbulence in
an iterated approach. The results show an important nonlinear effect of ion
diffusion, which can prevent the transition to the nonlinear regime at small
drive of the instability. At larger drive, quasi-coherent trajectory structures
appear and they have complex effects on turbulence.


title:
Reconstruction of semileptonically decaying beauty hadrons produced in
  high energy pp collisions

abstract:
  It is well known that in $b$ hadron decays with a single unreconstructible
final state particle, the decay kinematics can be solved up to a quadratic
ambiguity, without any knowledge of the $b$ hadron momentum. We present a
method to infer the momenta of $b$ hadrons produced in hadron collider
experiments using information from their reconstructed flight vectors. Our
method is strictly agnostic to the decay itself, which implies that it can be
validated with control samples of topologically similar decays to fully
reconstructible final states. A multivariate regression algorithm based on the
flight information provides a $b$ hadron momentum estimate with a resolution of
around 60% which is sufficient to select the correct solution to the quadratic
equation in around 70% of cases. This will improve the ability of hadron
collider experiments to make differential decay rate measurements with
semileptonic $b$ hadron decays.


title: On algebras of three-dimensional quaternionic harmonic fields

abstract:
  A quaternionic field is a pair $p=\{\alpha,u\}$ of function $\alpha$ and
vector field $u$ given on a 3d Riemannian maifold $\Omega$ with the boundary.
The field is said to be harmonic if $\nabla \alpha={\rm rot\,}u$\, in $\Omega$.
The linear space of harmonic fields is not an algebra w.r.t. quaternion
multiplication. However, it may contain the commutative algebras, what is the
subject of the paper. Possible application of these algebras to the impedance
tomography problem is touched on.


title: Configurational and energy landscape in one-dimensional Coulomb systems

abstract:
  We study a one dimensional Coulomb system, where two charged colloids are
neutralized by a collection of point counterions, with global neutrality.
Temperature being given, two situations are addressed: the colloids are either
kept at fixed positions (canonical ensemble), or the force acting on the
colloids is fixed (isobaric-isothermal ensemble). The corresponding partition
functions are worked out exactly, in view of determining which arrangement of
counterions is optimal: how many counterions should be in the confined segment
between the colloids? For the remaining ions outside, is there a left/right
symmetry breakdown? We evidence a cascade of transitions, as system size is
varied in the canonical treatment, or as pressure is increased in the isobaric
formulation.


title:
Nica-Toeplitz algebras associated with right tensor $C^*$-precategories
  over right LCM semigroups

abstract:
  We introduce and analyze the full $\mathcal{NT}_{\mathcal{L}}(\mathcal{K})$
and the reduced $\mathcal{NT}_{\mathcal{L}}^r(\mathcal{K})$ Nica-Toeplitz
algebra associated to an ideal $\mathcal{K}$ in a right tensor
$C^*$-precategory $\mathcal{L}$ over a right LCM semigroup $P$. Our main
results are uniqueness theorems in the spirit of classical Coburn's theorem,
generalizing uniqueness results for Toeplitz-type $C^*$-algebras associated to
single $C^*$-correspondences, quasi-lattice ordered semigroups, and crossed
products twisted by product systems of $C^*$-correspondences obtained by
Fowler, Laca and Raeburn.
  We formulate geometric conditions on a representation $\Phi$ of $\mathcal{K}$
so that the $C^*$-algebra it generates, $C^*(\Phi(\mathcal{K}))$, naturally
lies between $\mathcal{NT}_{\mathcal{L}}^r(\mathcal{K})$ and
$\mathcal{NT}_{\mathcal{L}}(\mathcal{K})$. Under suitable amenability
hypotheses, $C^*(\Phi(\mathcal{K}))$ and
$\mathcal{NT}_{\mathcal{L}}(\mathcal{K})$ are isomorphic. The geometric
conditions are necessary for our uniqueness result when the right tensoring
preserves $\mathcal{K}$ and in general they capture uniqueness of the
$C^*$-algebra generated by a natural extension of $\Phi$ to $\mathcal{L}$. In
particular, the latter algebra could be viewed as a Doplicher-Roberts version
of $\mathcal{NT}_{\mathcal{L}}(\mathcal{K})$.


title:
On the late phase of relaxation of two-dimensional fluids: turbulence of
  unitons

abstract:
  The two-dimensional ideal fluid and the plasma confined by a strong magnetic
field exhibit an intrinsic tendency to organization due to the inverse spectral
cascade. In the asymptotic states reached at relaxation the turbulence has
vanished and there are only coherent vortical structures. We are interested in
the regime that precedes these ordered flow patterns, in which there still is
turbulence and imperfect but robust structures have emerged. To develop an
analytical description we propose to start from the stationary coherent states
and (in the direction opposite to relaxation) explore the space of
configurations before the extremum of the functional that defines the
structures has been reached. We find necessary to assemble different but
related models: point-like vortices, its field theoretical formulation as
interacting matter and gauge fields, chiral model and surfaces with constant
mean curvature. These models are connected by the similar ability to describe
randomly interacting coherent structures. They derive exactly the same equation
for the asymptotic state (sinh-Poisson equation, confirmed by numerical
calculation of fluid flows). The chiral model, to which one can arrive from
self-duality equation of the field theoretical model for fluid and from
constant mean curvature surface equations, appears to be the suitable
analytical framework. Its solutions, the unitons, aquire dynamics when the
system is not at the extremum of the action. In the present work we provide
arguments that the underlying common nature of these models can be used to
develop an approach to fluid and plasma states of turbulence interacting with
structures.


title: Clickstream analysis for crowd-based object segmentation with confidence

abstract:
  With the rapidly increasing interest in machine learning based solutions for
automatic image annotation, the availability of reference annotations for
algorithm training is one of the major bottlenecks in the field. Crowdsourcing
has evolved as a valuable option for low-cost and large-scale data annotation;
however, quality control remains a major issue which needs to be addressed. To
our knowledge, we are the first to analyze the annotation process to improve
crowd-sourced image segmentation. Our method involves training a regressor to
estimate the quality of a segmentation from the annotator's clickstream data.
The quality estimation can be used to identify spam and weight individual
annotations by their (estimated) quality when merging multiple segmentations of
one image. Using a total of 29,000 crowd annotations performed on publicly
available data of different object classes, we show that (1) our method is
highly accurate in estimating the segmentation quality based on clickstream
data, (2) outperforms state-of-the-art methods for merging multiple
annotations. As the regressor does not need to be trained on the object class
that it is applied to it can be regarded as a low-cost option for quality
control and confidence analysis in the context of crowd-based image annotation.


title: $\mathrm{t\bar{t}H}$ production at $\mathrm{13\,TeV}$

abstract:
  In this paper, the latest results of searches for the standard model Higgs
boson produced in association with a top quark-antiquark pair
($\mathrm{t\bar{t}H}$), where Higgs decays into photons, bottom quark-antiquark
pair or leptons via $\mathrm{WW^*}$, $\mathrm{ZZ^*}$ and $\mathrm{\tau\tau}$
will be presented. The analyses have been performed using the
$\mathrm{13\,TeV}$ pp collisions data recorded by the CMS experiment in 2015
and part of 2016. The results are presented in the form of the best fit to the
signal strength ($\mathrm{\mu=\sigma/\sigma_{SM}}$) measured with respect to
the Standard Model prediction and its expected and observed $\mathrm{95\%}$
C.L. upper limits.


title:
The reduction of $G$-ordinary crystalline representations with
  $G$-structure

abstract:
  Fontaine's $D_{\mathrm{cris}}$ functor allow us to associate an isocrystal to
any crystalline representation. For a reductive group $G$, we study the
reduction of lattices inside a germ of crystalline representations with
$G$-structure $V$ to lattices (which are crystals) with $G$-structure inside
$D_{\mathrm{cris}}(V)$. Using Kisin modules theory, we give a description of
this reduction in terms of $G$, in the case when the representation $V$ is
($G$-)ordinary. In order to do that, first we need to generalize Fargues'
construction of the Harder-Narasimhan filtration for $p$-divisible groups to
Kisin modules.


title: Synthetic Observations of Magnetic Fields in Protostellar Cores

abstract:
  The role of magnetic fields in the early stages of star formation is not well
constrained. In order to discriminate between different star formation models,
we analyze 3D magnetohydrodynamic simulations of low-mass cores and explore the
correlation between magnetic field orientation and outflow orientation over
time. We produce synthetic observations of dust polarization at resolutions
comparable to millimeter-wave dust polarization maps observed by CARMA and
compare these with 2D visualizations of projected magnetic field and column
density. Cumulative distribution functions of the projected angle between the
magnetic field and outflow show different degrees of alignment in simulations
with differing mass-to-flux ratios. The distribution function for the less
magnetized core agrees with observations finding random alignment between
outflow and field orientations, while the more magnetized core exhibits
stronger alignment. We find that fractional polarization increases when the
system is viewed such that the magnetic field is close to the plane of the sky,
and the values of fractional polarization are consistent with observational
measurements. The simulation outflow, which reflects the underlying angular
momentum of the accreted gas, changes direction significantly over the first
$\sim0.1$ Myr of evolution. This movement could lead to the observed random
alignment between outflows and the magnetic fields in protostellar cores.


title:
Many-body localization and new critical phenomena in regular random
  graphs and constrained Erd\H{o}s-Renyi networks

abstract:
  We consider from the localization perspective the new critical phenomena
discovered recently for perturbed random regular graphs (RRG) and constrained
Erd\H{o}s-R\'enyi networks (CERN) \cite{crit2}. At some critical value of the
chemical potential of 3-cycles, $\mu$, the network decays into the maximally
possible number of almost full subgraphs, and the spectrum of the Laplacian
matrix acquires the two-zonal structure with a large gap. We find that the
Laplacian eigenvalue statistics corresponds to delocalized states in one zone,
and to the localized states in the second one. We interpret this behavior in
terms of the many-body localization problem where the structure of the Fock
space of some interacting many-body system is approximated by the RGG and/or by
the CERN. We associate 3-cycles in RRGs and CERNs as resonant triples in the
Fock space. We show that the scenario of the "localization without disorder",
discussed previously in physical space, can be realized in the Fock space as
well. We argue that it is natural to identify clusters in a RRG with particles
in a many-body system above the phase transition. We discuss the controversial
issue of an additional phase transition between ergodic and non-ergodic regimes
in the delocalized phase in the Fock space and find a strong "memory
dependence" of the states in the delocalized phase, thus advocating existence
of non-ergodic delocalized states.


title: Normal form for second order differential equations

abstract:
  We solve the local equivalence problem for second order (smooth or analytic)
ordinary differential equations. We do so by presenting a {\em complete
convergent normal form} for this class of ODEs. The normal form is optimal in
the sense that it is defined up to the automorphism group of the model (flat)
ODE $y"=0$. For a generic ODE, we also provide a unique normal form. By doing
so, we give a solution to a problem which remained unsolved since the work of
Arnold. The method can be immediately applied to important classes of second
order ODEs, in particular, the Painlev\'e equations.
  As another application of the convergent normal form, we discover
distinguished curves associated with a differential equation that we call {\em
chains}.


title: From $J/\psi$ to LHCb pentaquark

abstract:
  The original charmonium two-body problem, like the $c\bar c$ structure of the
$J/\psi$ meson, has become more involved in the last few years with the
discovery of new resonances such as the tentative molecular state $X(3872)$ or
the possible pentaquark one $P_{c}(4380)^{+}$. We discuss herein how these
exotic states (and others) can be described in a unified way adding higher Fock
state components to the naive quark model picture. In particular, we present
our theoretical results on the pentaquark states $P_{c}(4380)^{+}$ and
$P_{c}(4450)^{+}$, and on the new charmonium-like resonances $X(4140)$,
$X(4274)$, $X(4500)$ and $X(4700)$ that have been reported in $2016$ by the
LHCb Collaboration.


title: From $J/\psi$ to LHCb pentaquarks

abstract:
  The two exotic $P_c^+(4380)$ and $P_c^+(4450)$ discovered in $2015$ by the
LHCb Collaboration, together with the four resonances $X(4140)$, $X(4274)$,
$X(4500)$ and $X(4700)$, reported in $2016$ by the same collaboration, are
described in a constituent quark model which has been able to explain the
properties of charmonium states from the $J/\psi$ to the $X(3872)$. Using this
model we found a $\bar D\Sigma_c^*$ bound state with $J^P=\frac{3}{2}^-$ that
may be identified with the $P_c^+(4380)$. In the $\bar D^*\Sigma_c$ channel we
found three possible candidates for the $P_c^+(4450)$ with $J^P=\frac{1}{2}^-$,
$\frac{3}{2}^-$ and $\frac{3}{2}^+$ with almost degenerated energies. The
$X(4140)$ resonance appears as a cusp in the $J/\psi\phi$ channel due to the
near coincidence of the $D_{s}^{\pm}D_{s}^{\ast\pm}$ and $J/\psi\phi$ mass
thresholds. The remaining three $X(4274)$, $X(4500)$ and $X(4700)$ resonances
appear as conventional charmonium states with quantum numbers $3^{3}P_{1}$,
$4^{3}P_{0}$ and $5^{3}P_{0}$, respectively; and whose masses and widths are
slightly modified due to their coupling with the corresponding closest
meson-meson thresholds.


title:
A purification postulate for quantum mechanics with indefinite causal
  order

abstract:
  To study which are the most general causal structures which are compatible
with local quantum mechanics, Oreshkov et al. introduced the notion of a
process: a resource shared between some parties that allows for quantum
communication between them without a predetermined causal order. These
processes can be used to perform several tasks that are impossible in standard
quantum mechanics: they allow for the violation of causal inequalities, and
provide an advantage for computational and communication complexity.
Nonetheless, no process that can be used to violate a causal inequality is
known to be physically implementable. There is therefore considerable interest
in determining which processes are physical and which are just mathematical
artefacts of the framework. Here we make the first step in this direction, by
proposing a purification postulate: processes are physical only if they are
purifiable. We derive necessary conditions for a process to be purifiable, and
show that several known processes do not satisfy them.


title:
Time evolution of photon-pulse propagation in scattering and absorbing
  media: The dynamic radiative transfer system

abstract:
  A new dynamic system approach to the problem of radiative transfer inside
scattering and absorbing media is presented, directly based on firsthand
physical principles. This method, the Dynamic Radiative Transfer System (DRTS),
calculates accurately the time evolution of photon propagation in media of
complex structure and shape. DRTS employs a dynamical system formality using a
global sparse matrix which characterizes the physical, optical and geometrical
properties of the material volume of interest. The new system state vector is
generated by the above time-independent matrix, using simple matrix vector
multiplication addition for each subsequent time step. DRTS simulation results
are presented for 3D light propagation in different optical media,
demonstrating greatly reduced computational cost and resource requirements
compared to other methods. Flexibility of the method allows the integration of
time-dependent sources, boundary conditions, different media and several
optical phenomena like reflection and refraction in a unified and consistent
way.


title:
Sampling Rate Independent Filtration Approach for Automatic ECG
  Delineation

abstract:
  In this paper different types of ECG automatic delineation approaches were
overviewed. A combination of these approaches was used to create sampling rate
independent filtration algorithm for automatic ECG delineation that is capable
of distinguishing different morphologies of T and P waves and QRS complexes.
Created filtration algorithm was compared with algorithme \`a trous. It was
investigated that continuous wavelets transform with proposed automatic
adaptation for different sampling rates procedure can be used for delineation
problem.


title: Mass Renormlization in the Nelson Model

abstract:
  The asymptotic behavior of the effective mass $m_{\rm eff}(\Lambda)$ of the
so-called Nelson model in quantum field theory is considered, where $\Lambda$
is an ultraviolet cutoff parameter of the model. Let $m$ be the bare mass of
the model. It is shown that for sufficiently small coupling constant $|\alpha|$
of the model, $m_{{\rm eff}}(\Lambda)/m$ can be expanded as $m_{{\rm
eff}}(\Lambda)/m= 1+\sum_{n=1}^\infty a_n(\Lambda) \alpha^{2n}$. A physical
folklore is that $a_n(\Lambda)\sim [\log \Lambda]^{(n-1)}$ as $\Lambda\to
\infty$. It is rigorously shown that
$$0<\lim_{\Lambda\to\infty}a_1(\Lambda)<C,\quad C_1\leq
\lim_{\Lambda\to\infty}a_2(\Lambda)/\log\Lambda\leq C_2$$ with some constants
$C$, $C_1$ and $C_2$.


title:
Pinned-to-sliding transition and structural crossovers for helically
  confined charges

abstract:
  We explore the non-equilibrium dissipative dynamics of a system of identical
charged particles trapped on a closed helix. The particles are subject to an
external force accelerating them along the underlying structure. The effective
interactions between the charges induce a coupling of the center-of-mass to the
relative motion which in turn gives rise to a pinned-to-sliding transition with
increasing magnitude of the external force. In the sliding regime we observe an
Ohmic behaviour signified by a constant mobility. Within the same regime a
structural transition of the helical particle chain takes place with increasing
the helix radius leading to a global change of the crystalline arrangement. The
resulting crystal is characterized by the existence of multiple defects whose
number increases with the helix radius.


title:
Structure and Bonding in Amorphous Cr1-xCx Nanocomposite Thin Films:
  X-ray Absorption Spectra and First-Principles Calculation

abstract:
  The local structure and chemical bonding in two-phase amorphous
Cr$_{1-x}$C$_{x}$ nanocomposite thin films are investigated by Cr $K$-edge
($1s$) X-ray absorption near-edge structure (XANES) and extended X-ray
absorption fine structure (EXAFS) spectroscopies in comparison to theory. By
utilizing the computationally efficient \textit{stochastic quenching} (SQ)
technique, we reveal the complexity of different Cr-sites in the transition
metal carbides, highlighting the need for large scale averaging to obtain
theoretical XANES and EXAFS spectra for comparison with measurements. As shown
in this work, it is advantageous to use \textit{ab initio} theory as an
assessment to correctly model and fit experimental spectra and investigate the
trends of bond lengths and coordination numbers in complex amorphous materials.
With sufficient total carbon content ($\geq$ 30 at\%), we find that the
short-range coordination in the amorphous carbide phase exhibit similarities to
that of a Cr$_{7}$C$_{3\pm{}y}$ structure, while excessive carbons assemble in
the amorphous carbon phase.


title: Reasoning about Strategies: on the Satisfiability Problem

abstract:
  Strategy Logic (SL, for short) has been introduced by Mogavero, Murano, and
Vardi as a useful formalism for reasoning explicitly about strategies, as
first-order objects, in multi-agent concurrent games. This logic turns out to
be very powerful, subsuming all major previously studied modal logics for
strategic reasoning, including ATL, ATL*, and the like. Unfortunately, due to
its high expressiveness, SL has a non-elementarily decidable model-checking
problem and the satisfiability question is undecidable, specifically Sigma_1^1.
  In order to obtain a decidable sublogic, we introduce and study here One-Goal
Strategy Logic (SL[1G], for short). This is a syntactic fragment of SL,
strictly subsuming ATL*, which encompasses formulas in prenex normal form
having a single temporal goal at a time, for every strategy quantification of
agents. We prove that, unlike SL, SL[1G] has the bounded tree-model property
and its satisfiability problem is decidable in 2ExpTime, thus not harder than
the one for ATL*.


title: Proposal for witnessing non-classical light with the human eye

abstract:
  We give a complete proposal showing how to detect the non-classical nature of
photonic states with naked eyes as detectors. The enabling technology is a
sub-Poissonian photonic state that is obtained from single photons,
displacement operations in phase space and basic non-photon-number-resolving
detectors. We present a detailed statistical analysis of our proposal including
imperfect photon creation and detection and a realistic model of the human eye.
We conclude that a few tens of hours are sufficient to certify non-classical
light with the human eye with a p-value of 10%.


title:
Asymptotic properties of the volatility estimator from high frequency
  data modeled by mixed fractional Brownian motion

abstract:
  Properties of mixed fractional Brownian motion has been discussed by
Cheridito (2001) and Zili (2006). We have proposed an estimator of volatility
parameter for a model driven by MFBM. In our article we have shown that the
estimator has some desirable asymptotic properties.


title: Surgery on discrete groups

abstract:
  We study constructions of groups, in particular of groups of intermediate
rank, which are accessible to surgery techniques.


title:
Probability density cloud as a geometrical tool to describe statistics
  of scattered light

abstract:
  First-order statistics of scattered light is described using the
representation of probability density cloud which visualizes a two-dimensional
distribution for complex amplitude. The geometric parameters of the cloud are
studied in detail and are connected to the statistical properties of phase. The
moment-generating function for intensity is obtained in a closed form through
these parameters. An example of exponentially modified normal distribution is
provided to illustrate the functioning of this geometrical approach.


title:
Joint Throughput Maximization and Power Control in Poisson CoopMAC
  Networks

abstract:
  A cooperative medium access control (CoopMAC) network with randomly
distributed helpers is considered. We introduce a new helper selection scheme
which maximizes the average throughput while maintaining a low power
consumption profile in the network. To this end, all transmissions are assumed
to be performed using power control. We assume that each node can estimate the
channel between itself and a receiving node. Then, it evaluates the minimum
transmission power needed to achieve the desired signal to noise ratio (SNR).
If the required transmission power is less than the maximum transmission power
of the node, the communication is regarded as successful. Otherwise, the
transmission is canceled. %Also, we classify the helpers into six groups
according to their transmission rates IEEE 802.11b Standard. In order to
increase the average throughput, we assume that the cooperative link with the
highest transmission rate is chosen from those that can successfully forward
the source signal to destination. Also, when there are several links with the
same rates, the one with minimum required power is given the highest priority.
Assuming that the helpers are distributed as a Poisson point process with fixed
intensity, we derive exact expressions for the average throughput and the power
consumption of the network. Simulation results show that our scheme is able to
significantly increase the throughput in comparison to the conventional CoopMAC
network. It is also able to reduce the power consumption compared to a network
with no power control approach.


title:
The G-ACM Tool: using the Drools Rule Engine for Access Control
  Management

abstract:
  In this paper we explore the usage of rule engines in a graphical framework
for visualising dynamic access control policies. We use the Drools rule engine
to dynamically compute permissions, following the Category-Based Access Control
metamodel.


title:
Magnetism in the KBaRE(BO3)2 (RE=Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu)
  series: materials with a triangular rare earth lattice

abstract:
  We report the magnetic properties of compounds in the KBaRE(BO3)2 family (RE=
Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb), materials with a planar triangular lattice
composed of rare earth ions. The samples were analyzed by x-ray diffraction and
crystallize in the space group R-3m. Physical property measurements indicate
the compounds display predominantly antiferromagnetic interactions between
spins without any signs of magnetic ordering above 1.8 K. The ideal 2D rare
earth triangular layers in this structure type make it a potential model system
for investigating magnetic frustration in rare-earth-based materials.


title: On the critical probability in percolation

abstract:
  For percolation on finite transitive graphs, Nachmias and Peres suggested a
characterization of the critical probability based on the logarithmic
derivative of the susceptibility. As a first test-case, we study their
suggestion for the Erd\H{o}s-R\'enyi random graph G_{n,p}, and confirm that the
logarithmic derivative has the desired properties: (i) its maximizer lies
inside the critical window p=1/n+\Theta(n^{-4/3}), and (ii) the inverse of its
maximum value coincides with the \Theta(n^{-4/3})-width of the critical window.
We also prove that the maximizer is not located at p=1/n or p=1/(n-1), refuting
a speculation of Peres.


title:
The sum of it all: revealing collaboration patterns by combining
  authorship and acknowledgements

abstract:
  Acknowledgments are one of many conventions by which researchers publicly
bestow recognition towards individuals, organizations and institutions that
contributed in some way to the work that led to publication. Combining data on
both co-authors and acknowledged individuals, the present study analyses
disciplinary differences in researchers credit attribution practices in
collaborative context. Our results show that the important differences
traditionally observed between disciplines in terms of team size are greatly
reduced when acknowledgees are taken into account. Broadening the measurement
of collaboration beyond co-authorship by including individuals credited in the
acknowledgements allows for an assessment of collaboration practices and team
work that might be closer to the reality of contemporary research, especially
in the social sciences and humanities.


title: Compressive Spectral Renormalization Method

abstract:
  In this paper a novel numerical scheme for finding the sparse self-localized
states of a nonlinear system of equations with missing spectral data is
introduced. As in the Petviashivili's and the spectral renormalization method,
the governing equation is transformed into Fourier domain, but the iterations
are performed for far fewer number of spectral components (M) than classical
versions of the these methods with higher number of spectral components (N).
After the converge criteria is achieved for M components, N component signal is
reconstructed from M components by using the l1 minimization technique of the
compressive sampling. This method can be named as compressive spectral
renormalization (CSRM) method. The main advantage of the CSRM is that, it is
capable of finding the sparse self-localized states of the evolution
equation(s) with many spectral data missing.


title:
Investigating overdensities around z>6 galaxies through ALMA
  observations of [CII]

abstract:
  We present a search for companion [CII] emitters to known luminous sources at
$6<$ z $<6.5$ in deep, archival ALMA observations. The observations are deep
enough to detect sources with L$_{\rm [CII]} \sim 10^8$ at z $\sim6$. We
identify four robust line detections from a blind search of five deep fields
centered on ultra-luminous infrared galaxies and QSOs, over an order of
magnitude more than expected based on current observations and predictions,
suggesting that these objects may be highly biased tracers of mass in the early
Universe. We find these companion lines to have comparable properties to other
known galaxies at the same epoch. All companions lie less than 650 km s$^{-1}$
and between 20 -- 70 kpc (projected) from their central source, providing a
constraint on their halo masses of the central galaxies ranging from
2.5$\times$10$^{12}$ M$_\odot$ to 4$\times$10$^{13}$ M$_\odot$. To place these
discoveries in context, we employ a mock galaxy catalog to estimate the
luminosity function for [CII] during reionization and compare to our
observations. The simulations support this result by showing a similar level of
elevated counts found around such luminous sources.


title:
A moving mesh finite difference method for non-monotone solutions of
  non-equilibrium equations in porous media

abstract:
  An adaptive moving mesh finite difference method is presented to solve two
types of equations with dynamic capillary pressure term in porous media. One is
the non-equilibrium Richards Equation and the other is the modified
Buckley-Leverett equation. The governing equations are discretized with an
adaptive moving mesh finite difference method in the space direction and an
implicit-explicit method in the time direction. In order to obtain high quality
meshes, an adaptive time-dependent monitor function with directional control is
applied to redistribute the mesh grid in every time step, and a diffusive
mechanism is used to smooth the monitor function. The behaviors of the central
difference flux, the standard local Lax-Friedrich flux and the local
Lax-Friedrich flux with reconstruction are investigated by solving a 1D
modified Buckley-Leverett equation. With the moving mesh technique, good mesh
quality and high numerical accuracy are obtained. A collection of
one-dimensional and two-dimensional numerical experiments is presented to
demonstrate the accuracy and effectiveness of the proposed method.


title:
Asynchronous Distributed Automata: A Characterization of the Modal
  Mu-Fragment

abstract:
  We establish the equivalence between a class of asynchronous distributed
automata and a small fragment of least fixpoint logic, when restricted to
finite directed graphs. More specifically, the logic we consider is (a variant
of) the fragment of the modal $\mu$-calculus that allows least fixpoints but
forbids greatest fixpoints. The corresponding automaton model uses a network of
identical finite-state machines that communicate in an asynchronous manner and
whose state diagram must be acyclic except for self-loops. Exploiting the
connection with logic, we also prove that the expressive power of those
machines is independent of whether or not messages can be lost.


title: New Trends in Neutrosophic Theory and Applications

abstract:
  Neutrosophic theory and applications have been expanding in all directions at
an astonishing rate especially after the introduction the journal entitled
Neutrosophic Sets and Systems. New theories, techniques, algorithms have been
rapidly developed. One of the most striking trends in the neutrosophic theory
is the hybridization of neutrosophic set with other potential sets such as
rough set, bipolar set, soft set, hesitant fuzzy set, etc. The different hybrid
structure such as rough neutrosophic set, single valued neutrosophic rough set,
bipolar neutrosophic set, single valued neutrosophic hesitant fuzzy set, etc.
are proposed in the literature in a short period of time. Neutrosophic set has
been a very important tool in all various areas of data mining, decision
making, e-learning, engineering, medicine, social science, and some more. The
book New Trends in Neutrosophic Theories and Applications focuses on theories,
methods, algorithms for decision making and also applications involving
neutrosophic information. Some topics deal with data mining, decision making,
e-learning, graph theory, medical diagnosis, probability theory, topology, and
some more.


title: Block algebras with HH1 a simple Lie algebra

abstract:
  We show that if $B$ is a block of a finite group algebra $kG$ over an
algebraically closed field $k$ of prime characteristic $p$ such that $\HH^1(B)$
is a simple Lie algebra and such that $B$ has a unique isomorphism class of
simple modules, then $B$ is nilpotent with an elementary abelian defect group
$P$ of order at least $3$, and $\HH^1(B)$ is in that case isomorphic to the
Jacobson-Witt algebra $\HH^1(kP)$. In particular, no other simple modular Lie
algebras arise as $\HH^1(B)$ of a block $B$ with a single isomorphism class of
simple modules.


title: Concentration Compactness for Critical Radial Wave Maps

abstract:
  We consider radially symmetric, energy critical wave maps from (1 +
2)-dimensional Minkowski space into the unit sphere $\mathbb{S}^m$, $m \geq 1$,
and prove global regularity and scattering for classical smooth data of finite
energy. In addition, we establish a priori bounds on a suitable scattering norm
of the radial wave maps and exhibit concentration compactness properties of
sequences of radial wave maps with uniformly bounded energies. This extends and
complements the beautiful classical work of Christodoulou-Tahvildar-Zadeh [3,
4] and Struwe [31, 33] as well as of Nahas [22] on radial wave maps in the case
of the unit sphere as the target. The proof is based upon the concentration
compactness/rigidity method of Kenig-Merle [6, 7] and a "twisted"
Bahouri-Gerard type profile decomposition [1], following the implementation of
this strategy by the second author and Schlag [17] for energy critical wave
maps into the hyperbolic plane as well as by the last two authors [16] for the
energy critical Maxwell-Klein-Gordon equation.


title: Toeplitz and Asymptotic Toeplitz operators on $H^2(\mathbb{D}^n)$

abstract:
  We initiate a study of asymptotic Toeplitz operators on the Hardy space
$H^2(\mathbb{D}^n)$ (over the unit polydisc $\mathbb{D}^n$ in $\mathbb{C}^n$).
We also study the Toeplitz operators in the polydisc setting. Our main results
on Toeplitz and asymptotic Toeplitz operators can be stated as follows: Let
$T_{z_i}$ denote the multiplication operator on $H^2(\mathbb{D}^n)$ by the
$i^{th}$ coordinate function $z_i$, $i =1, \ldots, n$, and let $T$ be a bounded
linear operator on $H^2(\mathbb{D}^n)$. Then the following hold:
  (i) $T$ is a Toeplitz operator (that is, $T = P_{H^2(\mathbb{D}^n)}
M_{\varphi}|_{H^2(\mathbb{D}^n)}$, where $M_{\varphi}$ is the Laurent operator
on $L^{2}(\mathbb{T}^n)$ for some $\varphi \in L^\infty(\mathbb{T}^n)$) if and
only if $T_{z_i}^* T T_{z_i} = T$ for all $i = 1, \ldots, n$.
  (ii) $T$ is an asymptotic Toeplitz operator if and only if $T =
\mbox{~Toeplitz} + \mbox{~compact}$.
  The case $n = 1$ is the well known results of Brown and Halmos, and Feintuch,
respectively. We also present related results in the setting of vector-valued
Hardy spaces over the unit disc.


title:
More on the rainbow chain: entanglement, space-time geometry and thermal
  states

abstract:
  The rainbow chain is an inhomogenous exactly solvable local spin model that,
in its ground state, displays a half-chain entanglement entropy growing
linearly with the system size. Although many exact results about the rainbow
chain are known, the structure of the underlying quantum field theory has not
yet been unraveled. Here we show that the universal scaling features of this
model are captured by a massless Dirac fermion in a curved space-time with
constant negative curvature $R=-h^2$ ($h$ is the amplitude of the
inhomogeneity). This identification allows us to use recently developed
techniques to study inhomogeneous conformal systems and to analytically
characterise the entanglement entropies of more general bipartitions. These
results are carefully tested against exact numerical calculations. Finally, we
study the entanglement entropies of the rainbow chain in thermal states, and
find that there is a non-trivial interplay between the rainbow effective
temperature $T_R$ and the physical temperature $T$.


title: User Point Processes in Cellular Networks

abstract:
  The point process of concurrent users is critical for the analysis of
cellular networks, in particular for the uplink and for full-duplex
communication. We analyze the properties of two popular models. For the first
one, we provide an accurate characterization of the pair correlation functions
from the user and the base station point of view, which are applied to
approximate the user process by Poisson and Ginibre point processes. For the
second model, which includes the first model asymptotically, we study the cell
vacancy probability, the mean area of vacant and occupied cells, the user-base
station distance, and the pair correlation function in lightly and heavily
loaded regimes.


title:
A Tight Rate Bound and a Matching Construction for Locally Recoverable
  Codes with Sequential Recovery From Any Number of Multiple Erasures

abstract:
  An $[n,k]$ code $\mathcal{C}$ is said to be locally recoverable in the
presence of a single erasure, and with locality parameter $r$, if each of the
$n$ code symbols of $\mathcal{C}$ can be recovered by accessing at most $r$
other code symbols. An $[n,k]$ code is said to be a locally recoverable code
with sequential recovery from $t$ erasures, if for any set of $s \leq t$
erasures, there is an $s$-step sequential recovery process, in which at each
step, a single erased symbol is recovered by accessing at most $r$ other code
symbols. This is equivalent to the requirement that for any set of $s \leq t$
erasures, the dual code contain a codeword whose support contains the
coordinate of precisely one of the $s$ erased symbols. In this paper, a tight
upper bound on the rate of such a code, for any value of number of erasures $t$
and any value $r \geq 3$, of the locality parameter is derived. This bound
proves an earlier conjecture due to Song, Cai and Yuen. While the bound is
valid irrespective of the field over which the code is defined, a matching
construction of {\em binary} codes that are rate-optimal is also provided,
again for any value of $t$ and any value $r\geq3$.


title: A Simple, Fast Diverse Decoding Algorithm for Neural Generation

abstract:
  In this paper, we propose a simple, fast decoding algorithm that fosters
diversity in neural generation. The algorithm modifies the standard beam search
algorithm by adding an inter-sibling ranking penalty, favoring choosing
hypotheses from diverse parents. We evaluate the proposed model on the tasks of
dialogue response generation, abstractive summarization and machine
translation. We find that diverse decoding helps across all tasks, especially
those for which reranking is needed.
  We further propose a variation that is capable of automatically adjusting its
diversity decoding rates for different inputs using reinforcement learning
(RL). We observe a further performance boost from this RL technique. This paper
includes material from the unpublished script "Mutual Information and Diverse
Decoding Improve Neural Machine Translation" (Li and Jurafsky, 2016).


title:
Online Real-time Multiple Spatiotemporal Action Localisation and
  Prediction

abstract:
  We present a deep-learning framework for real-time multiple spatio-temporal
(S/T) action localisation, classification and early prediction. Current
state-of-the-art approaches work offline and are too slow to be useful in real-
world settings. To overcome their limitations we introduce two major
developments. Firstly, we adopt real-time SSD (Single Shot MultiBox Detector)
convolutional neural networks to regress and classify detection boxes in each
video frame potentially containing an action of interest. Secondly, we design
an original and efficient online algorithm to incrementally construct and label
`action tubes' from the SSD frame level detections. As a result, our system is
not only capable of performing S/T detection in real time, but can also perform
early action prediction in an online fashion. We achieve new state-of-the-art
results in both S/T action localisation and early action prediction on the
challenging UCF101-24 and J-HMDB-21 benchmarks, even when compared to the top
offline competitors. To the best of our knowledge, ours is the first real-time
(up to 40fps) system able to perform online S/T action localisation and early
action prediction on the untrimmed videos of UCF101-24.


title:
Existence of common hypercyclic subspaces for the derivative operator
  and the translation operators

abstract:
  We show that the non-zero multiples of the derivative operator and the
non-zero multiples of non-trivial translation operators on the space of entire
functions share a common hypercyclic subspace, i.e. a closed
infinite-dimensional subspace in which each non-zero vector has a dense orbit
for each of these operators.


title:
Eisenstein cocycles for GL(n) and values of L-functions in imaginary
  quadratic extensions

abstract:
  We generalize Sczech's Eisenstein cocycle for $\mathrm{GL}(n)$ over totally
real extensions of $\mathbb{Q}$ to finite extensions of imaginary quadratic
fields. By evaluating the cocycle on certain cycles, we parametrize complex
values of Hecke L-functions previously considered by Colmez, giving a
cohomological interpretation of his algebraicity result on special values of
the L-functions.


title: On Kostant Sections and Topological Nilpotence

abstract:
  Let G denote a connected, quasi-split reductive group over a field F that is
complete with respect to a discrete valuation and that has a perfect residue
field. Under mild hypotheses, we produce a subset of the Lie algebra g(F) that
picks out a G(F)-conjugacy class in every stable, regular, topologically
nilpotent conjugacy class in g(F). This generalizes an earlier result obtained
by DeBacker and one of the authors under stronger hypotheses. We then show that
if F is p-adic, then the characteristic function of this set behaves well with
respect to endoscopic transfer.


title:
Re-appraisal and extension of the Gratton-Vargas two-dimensional
  analytical snowplow model of plasma focus - III: Scaling theory for high
  pressure operation and its implications

abstract:
  Recent work on the revised Gratton-Vargas model has demonstrated that there
are some aspects of Dense Plasma Focus (DPF) which are not sensitive to details
of plasma dynamics and are well captured in an oversimplified model assumption
which contains very little plasma physics. A hyperbolic conservation law
formulation of DPF physics reveals the existence of a velocity threshold
related to specific energy of dissociation and ionization, above which, the
work done during shock propagation is adequate to ensure dissociation and
ionization of the gas being ingested. These developments are utilized to
formulate an algorithmic definition of DPF optimization that is valid in a wide
range of applications, not limited to neutron emission. A universal scaling
theory of DPF design optimization is proposed and illustrated for designing
devices working at one or two orders higher pressure of deuterium than the
current practice of designs optimized at pressures less than 10 mbar of
deuterium. These examples show that the upper limit for operating pressure is
of technological (and not physical) origin.


title: Bottleneck Conditional Density Estimation

abstract:
  We introduce a new framework for training deep generative models for
high-dimensional conditional density estimation. The Bottleneck Conditional
Density Estimator (BCDE) is a variant of the conditional variational
autoencoder (CVAE) that employs layer(s) of stochastic variables as the
bottleneck between the input $x$ and target $y$, where both are
high-dimensional. Crucially, we propose a new hybrid training method that
blends the conditional generative model with a joint generative model. Hybrid
blending is the key to effective training of the BCDE, which avoids overfitting
and provides a novel mechanism for leveraging unlabeled data. We show that our
hybrid training procedure enables models to achieve competitive results in the
MNIST quadrant prediction task in the fully-supervised setting, and sets new
benchmarks in the semi-supervised regime for MNIST, SVHN, and CelebA.


title: Dynamics of the cosmological relaxation after reheating

abstract:
  We examine if the cosmological relaxation mechanism, which was proposed
recently as a new solution to the hierarchy problem, can be compatible with
high reheating temperature well above the weak scale. As the barrier potential
disappears at high temperature, the relaxion rolls down further after the
reheating, which may ruin the successful implementation of the relaxation
mechanism. It is noted that if the relaxion is coupled to a dark gauge boson,
the new frictional force arising from dark gauge boson production can
efficiently slow down the relaxion motion, which allows the relaxion to be
stabilized after the electroweak phase transition for a wide range of model
parameters, while satisfying the known observational constraints.


title: Ab initio calculation of the potential bubble nucleus $^{34}$Si

abstract:
  The possibility that an unconventional depletion in the center of the charge
density distribution of certain nuclei occurs due to a purely quantum
mechanical effect has attracted theoretical and experimental attention in
recent years. We report on ab initio self-consistent Green's function
calculations of one of such candidates, $^{34}$Si, together with its Z+2
neighbour $^{36}$S. Binding energies, rms radii and density distributions of
the two nuclei as well as low-lying spectroscopy of $^{35}$Si, $^{37}$S,
$^{33}$Al and $^{35}$P are discussed. The interpretation of one-nucleon removal
and addition spectra in terms of the evolution of the underlying shell
structure is also provided. The study is repeated using several chiral
effective field theory Hamiltonians as a way to test the robustness of the
results with respect to input inter-nucleon interactions. The prediction
regarding the (non-)existence of the bubble structure in $^{34}$Si varies
significantly with the nuclear Hamiltonian used. However, demanding that the
experimental charge density distribution and the root mean square radius of
$^{36}$S are well reproduced, along with $^{34}$Si and $^{36}$S binding
energies, only leaves the NNLO$_{\text{sat}}$ Hamiltonian as a serious
candidate to perform this prediction. In this context, a bubble structure,
whose fingerprint should be visible in an electron scattering experiment of
$^{34}$Si, is predicted. Furthermore, a clear correlation is established
between the occurrence of the bubble structure and the weakening of the
1/2$^-$-3/2$^-$ splitting in the spectrum of $^{35}$Si as compared to $^{37}$S.


title:
On preparing ground states of gapped Hamiltonians: An efficient Quantum
  Lov\'asz Local Lemma

abstract:
  A frustration-free local Hamiltonian has the property that its ground state
minimises the energy of all local terms simultaneously. In general, even
deciding whether a Hamiltonian is frustration-free is a hard task, as it is
closely related to the QMA1-complete quantum satisfiability problem (QSAT) --
the quantum analogue of SAT, which is the archetypal NP-complete problem in
classical computer science. This connection shows that the frustration-free
property is not only relevant to physics but also to computer science. The
Quantum Lov\'asz Local Lemma (QLLL) provides a sufficient condition for
frustration-freeness. A natural question is whether there is an efficient way
to prepare a frustration-free state under the conditions of the QLLL. Previous
results showed that the answer is positive if all local terms commute. In this
work we improve on the previous constructive results by designing an algorithm
that works efficiently for non-commuting terms as well, assuming that the
system is "uniformly" gapped, by which we mean that the system and all its
subsystems have an inverse polynomial energy gap. Also, our analysis works
under the most general condition for the QLLL, known as Shearer's bound.
Similarly to the previous results, our algorithm has the charming feature that
it uses only local measurement operations corresponding to the local
Hamiltonian terms.


title: Bipolar Weighted Argumentation Graphs

abstract:
  This paper discusses the semantics of weighted argumentation graphs that are
biplor, i.e. contain both attacks and support graphs. The work builds on
previous work by Amgoud, Ben-Naim et. al., which presents and compares several
semantics for argumentation graphs that contain only supports or only attacks
relationships, respectively.


title: The Marriage of Incremental and Approximate Computing

abstract:
  Most data analytics systems that require low-latency execution and efficient
utilization of computing resources, increasingly adopt two computational
paradigms, namely, incremental and approximate computing. Incremental
computation updates the output incrementally instead of re-computing everything
from scratch for successive runs of a job with input changes. Approximate
computation returns an approximate output for a job instead of the exact
output.
  Both paradigms rely on computing over a subset of data items instead of
computing over the entire dataset, but they differ in their means for skipping
parts of the computation. Incremental computing relies on the memoization of
intermediate results of sub-computations, and reusing these memoized results
across jobs for sub-computations that are unaffected by the changed input.
Approximate computing relies on representative sampling of the entire dataset
to compute over a subset of data items.
  In this thesis, we make the observation that these two computing paradigms
are complementary, and can be married together! The high level idea is to:
design a sampling algorithm that biases the sample selection to the memoized
data items from previous runs. To concretize this idea, we designed an online
stratified sampling algorithm that uses self-adjusting computation to produce
an incrementally updated approximate output with bounded error. We implemented
our algorithm in a data analytics system called IncAppox based on Apache Spark
Streaming. Our evaluation of the system shows that IncApprox achieves the
benefits of both incremental and approximate computing.


title: An Efficient Streaming Algorithm for the Submodular Cover Problem

abstract:
  We initiate the study of the classical Submodular Cover (SC) problem in the
data streaming model which we refer to as the Streaming Submodular Cover (SSC).
We show that any single pass streaming algorithm using sublinear memory in the
size of the stream will fail to provide any non-trivial approximation
guarantees for SSC. Hence, we consider a relaxed version of SSC, where we only
seek to find a partial cover.
  We design the first Efficient bicriteria Submodular Cover Streaming
(ESC-Streaming) algorithm for this problem, and provide theoretical guarantees
for its performance supported by numerical evidence. Our algorithm finds
solutions that are competitive with the near-optimal offline greedy algorithm
despite requiring only a single pass over the data stream. In our numerical
experiments, we evaluate the performance of ESC-Streaming on active set
selection and large-scale graph cover problems.


title: Event Shape Sorting: selecting events with similar evolution

abstract:
  We present novel method for the organisation of events. The method is based
on comparing event-by-event histograms of a chosen quantity Q that is measured
for each particle in every event. The events are organised in such a way that
those with similar shape of the Q-histograms end-up placed close to each other.
We apply the method on histograms of azimuthal angle of the produced hadrons in
ultrarelativsitic nuclear collisions. By selecting events with similar
azimuthal shape of their hadron distribution one chooses events which are
likely that they underwent similar evolution from the initial state to the
freeze-out. Such events can more easily be compared to theoretical simulations
where all conditions can be controlled. We illustrate the method on data
simulated by the AMPT model.

categories: physics.data-an hep-ex hep-ph nucl-ex nucl-th


title:
Long-term photometric behavior of the PMS stars V977 Cep and V982 Cep in
  the vicinity of NGC 7129

abstract:
  Long-term BVRI photometric light curves of the pre-main sequence stars V977
Cep and V982 Cep during the period from 2000 October to 2016 August are
presented. The stars are located in the vicinity of the reflection nebula NGC
7129. Our photometric data show that both stars exhibit strong photometric
variability in all optical passbands, which is typical for Classical T Tauri
stars. Using our observational data we analyze the reasons for the observed
brightness variations. In the case of V977 Cep we identify previously unknown
periodicity in its light curve.


title:
Flow anisotropy due to momentum deposition in ultra-relativistic nuclear
  collisions

abstract:
  Minijets and jets are produced in large numbers in nuclear collisions at TeV
energies, so that there are many of them in a single fireball. They deposit
non-negligible amount of momentum and energy into the hydrodynamically
expanding bulk and cause anisotropies of the expansion. Moreover, due to their
multiple production in a single event the resulting anisotropies are correlated
with the collision geometry and thus contribute positively also to
event-averaged anisotropies in non-central collisions. Using simulations with
three-dimensional ideal hydrodynamic model we demonstrate the importance of
this effect. It must be taken into account if conclusions about the properties
of the hot matter are to be drawn.


title: The effect of finger spreading on drag of the hand in human swimming

abstract:
  The effect of finger spreading on hydrodynamic drag in swimming is studied
both with a numerical simulation and with laboratory experiments. Both
approaches are based on the exact same 3D model of the hand with attached
forearm. The virtual version of the hand with forearm was implemented in a
numerical code by means of an immersed boundary method and the physical version
was studied in a wind tunnel experiment. An enhancement of the drag coefficient
of 2 and 5% compared to the case with closed fingers was found for the
numerical simulation and experiment, respectively. A 5 and 8% favourable effect
on the (dimensionless) force moment at an optimal finger spreading of 10
degrees was found, which indicates that the difference is more outspoken in the
force moment. Also an analytical model is proposed, using scaling arguments
similar to the Betz actuator disk model, to explain the drag coefficient as a
function of finger spacing.


title: Noncentrosymmetric superconductors in one dimension

abstract:
  We study the fermionic boundary modes (Andreev bound states) in a
time-reversal invariant one-dimensional superconductor. In the presence of a
substrate, spatial inversion symmetry is broken and the electronic properties
are strongly affected by an antisymmetric spin-orbit coupling. We assume an
arbitrary even number of nondegenerate bands crossing the Fermi level. We show
that there is only one possible pairing symmetry in one dimension, an analog of
s-wave pairing. The zero-energy Andreev bound states are present if the sign of
the gap function in an odd number of bands is different from all other bands.


title:
On computing distributions of products of random variables via Gaussian
  multiresolution analysis

abstract:
  We introduce a new approximate multiresolution analysis (MRA) using a single
Gaussian as the scaling function, which we call Gaussian MRA (GMRA). As an
initial application, we employ this new tool to accurately and efficiently
compute the probability density function (PDF) of the product of independent
random variables. In contrast with Monte-Carlo (MC) type methods (the only
other universal approach known to address this problem), our method not only
achieves accuracies beyond the reach of MC but also produces a PDF expressed as
a Gaussian mixture, thus allowing for further efficient computations. We also
show that an exact MRA corresponding to our GMRA can be constructed for a
matching user-selected accuracy.


title: Towards a dS/MERA correspondence

abstract:
  Recent advances have suggested that spacetime itself emerges from the
entanglement of the quantum degrees of freedom living on the boundary. In the
case of the AdS spacetimes, a particular class of tensor networks has been
shown to realize the same via Multi-Scale Entanglement Renormalization Ansatz
(MERA). In this paper we suggest a prescription for the dS/MERA correspondence
and recover a discrete version of de Sitter Penrose diagram by using the MERA
on conformal theories identified with the future/past conformal boundaries of
the de Sitter spacetime. As anticipated, time appears as the emergent
direction. We comment on the possible interpretation that the de Sitter
cosmological horizon entropy involves entanglement with degrees of freedom
across the cosmological horizon as well as the implications of our construction
for cosmology.


title:
Absence of high-temperature ballistic transport in the spin-$1/2$ $XXX$
  chain within the grand-canonical ensemble

abstract:
  Whether in the thermodynamic limit, vanishing magnetic field $h\rightarrow
0$, and nonzero temperature the spin stiffness of the spin-$1/2$ $XXX$
Heisenberg chain is finite or vanishes within the grand-canonical ensemble
remains an unsolved and controversial issue, as different approaches yield
contradictory results. Here we provide an upper bound on the stiffness and show
that within that ensemble it vanishes for $h\rightarrow 0$ in the thermodynamic
limit of chain length $L\to\infty$, at high temperatures $T\rightarrow\infty$.
Our approach uses a representation in terms of the $L$ physical spins $1/2$.
For all configurations that generate the exact spin-$S$ energy and momentum
eigenstates such a configuration involves a number $2S$ of unpaired spins $1/2$
in multiplet configurations and $L-2S$ spins $1/2$ that are paired within
$M_{\rm sp}=L/2-S$ spin-singlet pairs. The Bethe-ansatz strings of length $n=1$
and $n>1$ describe a single unbound spin-singlet pair and a configuration
within which $n$ pairs are bound, respectively. In the case of $n>1$ pairs this
holds both for ideal and deformed strings associated with $n$ complex
rapidities with the same real part. The use of such a spin $1/2$ representation
provides useful physical information on the problem under investigation in
contrast to often less controllable numerical studies. Our results provide
strong evidence for the absence of ballistic transport in the spin-$1/2$ $XXX$
Heisenberg chain in the thermodynamic limit, for high temperatures
$T\to\infty$, vanishing magnetic field $h\rightarrow 0$ and within the
grand-canonical ensemble.