title:
Polarized Synchrotron Emissivities and Absorptivities for Relativistic
  Thermal, Power-Law, and Kappa Distribution Functions

abstract:
  Synchrotron emission and absorption determine the observational appearance of
many astronomical systems. In this paper, we describe a numerical scheme for
calculating synchrotron emissivities and absorptivities in all four Stokes
parameters for arbitrary gyrotropic electron distribution functions, building
on earlier work by Leung, Gammie, and Noble. We use this technique to evaluate
the emissivities and the absorptivities for a thermal (Maxwell-J\"uttner),
isotropic power-law, and isotropic kappa distribution function. The latter
contains a power-law tail at high particle energies that smoothly merges with a
thermal core at low energies, as is characteristic of observed particle spectra
in collisionless plasmas. We provide fitting formulae and error bounds on the
fitting formulae for use in codes that solve the radiative transfer equation.
The numerical method and the fitting formulae are implemented in a compact C
library called ${\tt symphony}$. We find that: the kappa distribution has a
source function that is indistinguishable from a thermal spectrum at low
frequencies and transitions to the characteristic self-absorbed synchrotron
spectrum, $\propto \nu^{5/2}$, at high frequency; the linear polarization
fraction for a thermal spectrum is near unity at high frequency; and all
distributions produce $O(10\%)$ circular polarization at low frequency for
lines of sight sufficiently close to the magnetic field vector.


title:
Filtering Video Noise as Audio with Motion Detection to Form a Musical
  Instrument

abstract:
  Even though they differ in the physical domain, digital video and audio share
many characteristics. Both are temporal data streams often stored in buffers
with 8-bit values. This paper investigates a method for creating harmonic
sounds with a video signal as input. A musical instrument is proposed, that
utilizes video in both a sound synthesis method, and in a controller interface
for selecting musical notes at specific velocities. The resulting instrument
was informally determined by the author to sound both pleasant and interesting,
but hard to control, and therefore suited for synth pad sounds.


title: Extracting Information from Multiplex Networks

abstract:
  Multiplex networks are generalized network structures that are able to
describe networks in which the same set of nodes are connected by links that
have different connotations. Multiplex networks are ubiquitous since they
describe social, financial, engineering and biological networks as well.
Extending our ability to analyze complex networks to multiplex network
structures increases greatly the level of information that is possible to
extract from Big Data. For these reasons characterizing the centrality of nodes
in multiplex networks and finding new ways to solve challenging inference
problems defined on multiplex networks are fundamental questions of network
science. In this paper we discuss the relevance of the Multiplex PageRank
algorithm for measuring the centrality of nodes in multilayer networks and we
characterize the utility of the recently introduced indicator function
$\widetilde{\Theta}^{S}$ for describing their mesoscale organization and
community structure. As working examples for studying these measures we
consider three multiplex network datasets coming for social science.


title:
Goldilocks Probes for Noisy Interferometry via Quantum Annealing to
  Criticality

abstract:
  Quantum annealing is explored as a resource for quantum information beyond
solution of classical combinatorial problems. Envisaged as a generator of
robust interferometric probes, we examine a Hamiltonian of $N>> 1$
uniformly-coupled spins subject to a transverse magnetic field. The discrete
many-body problem is mapped onto dynamics of a single one-dimensional particle
in a continuous potential. This reveals all the qualitative features of the
ground state beyond typical mean-field or large classical spin models. It
illustrates explicitly a graceful warping from an entangled unimodal to
bi-modal ground state in the phase transition region. The transitional
`Goldilocks' probe has a component distribution of width $N^{2/3}$ and exhibits
characteristics for enhanced phase estimation in a decoherent environment. In
the presence of realistic local noise and collective dephasing, we find this
probe state asymptotically saturates ultimate precision bounds calculated
previously. By reducing the transverse field adiabatically, the Goldilocks
probe is prepared in advance of the minimum gap bottleneck, allowing the
annealing schedule to be terminated `early'. Adiabatic time complexity of probe
preparation is shown to be linear in $N$


title:
Stability and Structural Properties of Gene Regulation Networks with
  Coregulation Rules

abstract:
  Coregulation of the expression of groups of genes has been extensively
demonstrated empirically in bacterial and eukaryotic systems. Such coregulation
can arise through the use of shared regulatory motifs, which allow the
coordinated expression of modules (and module groups) of functionally related
genes across the genome. Coregulation can also arise through the physical
association of multi-gene complexes through chromosomal looping, which are then
transcribed together. We present a general formalism for modeling coregulation
rules in the framework of Random Boolean Networks (RBN), and develop specific
models for transcription factor networks with modular structure (including
module groups, and multi-input modules (MIM) with autoregulation) and
multi-gene complexes (including hierarchical differentiation between multi-gene
complex members). We develop a mean-field approach to analyse the stability of
large networks incorporating coregulation, and show that autoregulated MIM and
hierarchical gene-complex models can achieve greater stability than networks
without coregulation whose rules have matching activation frequency. We provide
further analysis of the stability of small networks of both kinds through
simulations. We also characterize several general properties of the transients
and attractors in the hierarchical coregulation model, and show using
simulations that the steady-state distribution factorizes hierarchically as a
Bayesian network in a Markov Jump Process analogue of the RBN model.


title: Adjusting for Scorekeeper Bias in NBA Box Scores

abstract:
  Box score statistics in the National Basketball Association are used to
measure and evaluate player performance. Some of these statistics are
subjective in nature and since box score statistics are recorded by
scorekeepers hired by the home team for each game, there exists potential for
inconsistency and bias. These inconsistencies can have far reaching
consequences, particularly with the rise in popularity of daily fantasy sports.
Using box score data, we estimate models able to quantify both the bias and the
generosity of each scorekeeper for two of the most subjective statistics:
assists and blocks. We then use optical player tracking data for the 2014-2015
season to improve the assist model by including other contextual
spatio-temporal variables such as time of possession, player locations, and
distance traveled. From this model, we present results measuring the impact of
the scorekeeper and of the other contextual variables on the probability of a
pass being recorded as an assist. Results for adjusting season assist totals to
remove scorekeeper influence are also presented.


title:
Sparsity of p-divisible unramified liftings for subvarieties of abelian
  varieties with trivial stabilizer

abstract:
  By means of the theory of strongly semistable sheaves and of the theory of
the Greenberg transform, we generalize to higher dimensions a result on the
sparsity of p-divisible unramified liftings which played a crucial role in
Raynaud's proof of the Manin-Mumford conjecture for curves. We also give a
bound for the number of irreducible components of the first critical scheme of
subvarieties of an abelian variety which are complete intersections.


title:
Revealing the broad iron Kalpha line in Cygnus X-1 through simultaneous
  XMM-Newton, RXTE, and INTEGRAL observations

abstract:
  We report on the analysis of the broad Fe Kalpha line feature of Cygnus X-1
in the spectra of four simultaneous hard intermediate state observations made
with the X-ray Multiple Mirror mission (XMM-Newton), the Rossi X-ray Timing
Explorer (RXTE), and the International Gamma-Ray Astrophysics Laboratory
(INTEGRAL). The high quality of the XMM-Newton data taken in the Modified
Timing Mode of the EPIC-pn camera provides a great opportunity to investigate
the broadened Fe Kalpha reflection line at 6.4keV with a very high signal to
noise ratio. The 4-500keV energy range is used to constrain the underlying
continuum and the reflection at higher energies. We first investigate the data
by applying a phenomenological model that consists of the sum of an
exponentially cutoff power law and relativistically smeared reflection.
Additionally, we apply a more physical approach and model the irradiation of
the accretion disk directly from the lamp post geometry. All four observations
show consistent values for the black hole parameters with a spin of $a\sim
0.9$, in agreement with recent measurements from reflection and disk continuum
fitting. The inclination is found to be $i\sim30^\circ$, consistent with the
orbital inclination and different from inclination measurements made during the
soft state, which show a higher inclination. We speculate that the difference
between the inclination measurements is due to changes in the inner region of
the accretion disk.


title: A direct approach to the anisotropic Plateau problem

abstract:
  We prove a compactness principle for the anisotropic formulation of the
Plateau problem in codimension one, along the same lines of previous works of
the authors [DGM14, DPDRG15]. In particular, we perform a new strategy for
proving the rectifiability of the minimal set, avoiding the Preiss'
Rectifiability Theorem [Pre87].


title:
Beyond the ponderomotive limit: direct laser acceleration of
  relativistic electrons in sub-critical plasmas

abstract:
  We examine a regime in which a linearly-polarized laser pulse with
relativistic intensity irradiates a sub-critical plasma for much longer than
the characteristic electron response time. A steady-state channel is formed in
the plasma in this case with quasi-static transverse and longitudinal electric
fields. These relatively weak fields significantly alter the electron dynamics.
The longitudinal electric field reduces the longitudinal dephasing between the
electron and the wave, leading to an enhancement of the electron energy gain
from the pulse. The energy gain in this regime is ultimately limited by the
superluminosity of the wave fronts induced by the plasma in the channel. The
transverse electric field alters the oscillations of the transverse electron
velocity, allowing it to remain anti-parallel to laser electric field and
leading to a significant energy gain. The energy enhancement is accompanied by
development of significant oscillations perpendicular to the plane of the
driven motion, making trajectories of energetic electrons three-dimensional.
Proper electron injection into the laser beam can further boost the electron
energy gain.


title: Did GW150914 produce a rotating gravastar?

abstract:
  The interferometric LIGO detectors have recently measured the first direct
gravitational-wave signal from what has been interpreted as the inspiral,
merger and ringdown of a binary system of black holes. The signal-to-noise
ratio of the measured signal is large enough to leave little doubt that it does
refer to the inspiral of two massive and ultracompact objects, whose merger
yields a rotating black hole. Yet, the quality of the data is such that some
room is left for alternative interpretations that do not involve black holes,
but other objects that, within classical general relativity, can be equally
massive and compact, namely, gravastars. We here consider the hypothesis that
the merging objects were indeed gravastars and explore whether the merged
object could therefore be not a black hole but a rotating gravastar. After
comparing the real and imaginary parts of the ringdown signal of GW150914 with
the corresponding quantities for a variety of gravastars, and notwithstanding
the very limited knowledge of the perturbative response of rotating gravastars,
we conclude it is not possible to model the measured ringdown of GW150914 as
due to a rotating gravastar.


title: Valuation theory of indefinite orthogonal groups

abstract:
  Let $\mathrm{SO}^+(p,q)$ denote the identity connected component of the real
orthogonal group with signature $(p,q)$. We give a complete description of the
spaces of continuous and generalized translation- and
$\mathrm{SO}^+(p,q)$-invariant valuations, generalizing Hadwiger's
classification of Euclidean isometry-invariant valuations. As a result of
independent interest, we identify within the space of translation-invariant
valuations the class of Klain-Schneider continuous valuations, which strictly
contains all continuous translation-invariant valuations. The operations of
pull-back and push-forward by a linear map extend naturally to this class.


title: Resource Constrained Structured Prediction

abstract:
  We study the problem of structured prediction under test-time budget
constraints. We propose a novel approach applicable to a wide range of
structured prediction problems in computer vision and natural language
processing. Our approach seeks to adaptively generate computationally costly
features during test-time in order to reduce the computational cost of
prediction while maintaining prediction performance. We show that training the
adaptive feature generation system can be reduced to a series of structured
learning problems, resulting in efficient training using existing structured
learning algorithms. This framework provides theoretical justification for
several existing heuristic approaches found in literature. We evaluate our
proposed adaptive system on two structured prediction tasks, optical character
recognition (OCR) and dependency parsing and show strong performance in
reduction of the feature costs without degrading accuracy.


title:
Search for heavy resonances decaying to two Higgs bosons in final states
  containing four b quarks

abstract:
  A search is presented for narrow heavy resonances X decaying into pairs of
Higgs bosons (H) in proton-proton collisions collected by the CMS experiment at
the LHC at sqrt(s) = 8 TeV. The data correspond to an integrated luminosity of
19.7 inverse femtobarns. The search considers HH resonances with masses between
1 and 3 TeV, having final states of two b quark pairs. Each Higgs boson is
produced with large momentum, and the hadronization products of the pair of b
quarks can usually be reconstructed as single large jets. The background from
multijet and t t-bar events is significantly reduced by applying requirements
related to the flavor of the jet, its mass, and its substructure. The signal
would be identified as a peak on top of the dijet invariant mass spectrum of
the remaining background events. No evidence is observed for such a signal.
Upper limits obtained at 95% confidence level for the product of the production
cross section and branching fraction sigma(gg to X) B(X to HH to b b-bar b
b-bar) range from 10 to 1.5 fb for the mass of X from 1.15 to 2.0 TeV,
significantly extending previous searches. For a warped extra dimension theory
with a mass scale Lambda[R] = 1 TeV, the data exclude radion scalar masses
between 1.15 and 1.55 TeV.


title:
Fast drift effects in the averaging of a filtration combustion system -
  a periodic homogenization approach

abstract:
  We target at the periodic homogenization of a semi-linear
reaction-diffusion-convection system describing filtration combustion, where
fast drifts affect the competition between heat and mass transfer processes as
well as the interplay between the surface nonlinear chemical reactions and the
transport processes. To handle the heterogeneity of the medium, we rely on the
concept of two-scale convergence with drift to obtain for suitably scaled model
parameters the upscaled system of combustion equations together with the
effective transport and reaction parameters. The main difficulty here is to
treat the case of the system combined with the nonlinearity of the surface
production.


title:
iPTF Search for an Optical Counterpart to Gravitational Wave Trigger
  GW150914

abstract:
  The intermediate Palomar Transient Factory (iPTF) autonomously responded to
and promptly tiled the error region of the first gravitational wave event
GW150914 to search for an optical counterpart. Only a small fraction of the
total localized region was immediately visible in the Northern night sky, due
both to sun-angle and elevation constraints. Here, we report on the transient
candidates identified and rapid follow-up undertaken to determine the nature of
each candidate. Even in the small area imaged of 126 sq deg, after extensive
filtering, 8 candidates were deemed worthy of additional follow-up. Within two
hours, all 8 were spectroscopically classified by the Keck II telescope.
Curiously, even though such events are rare, one of our candidates was a
superluminous supernova. We obtained radio data with the Jansky Very Large
Array and X-ray follow-up with the Swift satellite for this transient. None of
our candidates appear to be associated with the gravitational wave trigger,
which is unsurprising given that GW150914 came from the merger of two
stellar-mass black holes. This end-to-end discovery and follow-up campaign
bodes well for future searches in this post-detection era of gravitational
waves.


title: Designing A Dimmable OPPM-Based VLC System Under Channel Constraints

abstract:
  In this paper, we design a dimming compatible visible light communication
(VLC) system in a standard office room according to illumination standards
under channel constraints. We use overlapping pulse position modulation (OPPM)
to support dimming control by changing the code weights. The system parameters
such as a valid interval for dimming together with an upper bound for bit rate
according to the channel delay spread are investigated. Moreover, considering
the dispersive VLC channel and using Monte Carlo (MC) simulations, a method is
proposed to determine the minimum code length in different dimming levels in
order to achieve a valid bit error rate (BER).
  Finally, trellis coded modulation (TCM) is suggested to be applied to OPPM in
order to take advantage of consequent coding gain which could be up to $3$ dB.


title:
Impact of nonstandard interactions on sterile neutrino searches at
  IceCube

abstract:
  We analyze the energy and zenith angle distributions of the latest 2-year
IceCube dataset of upward going atmospheric neutrinos to constrain sterile
neutrinos at the eV scale in the 3+1 scenario. We find that the parameters
favored by a combination of LSND and MiniBooNE data are excluded at more than
the 99% C.L. We explore the impact of nonstandard matter interactions on this
exclusion, and find that the exclusion holds for nonstandard interactions (NSI)
that are within the stringent model-dependent bounds set by collider and
neutrino scattering experiments. However, for large NSI parameters subject only
to model-independent bounds from neutrino oscillation experiments, the LSND and
MiniBooNE data are consistent with IceCube.


title: Mergers of accreting stellar-mass black holes

abstract:
  We present post-Newtonian $N$-body simulations on mergers of accreting
stellar-mass black holes (BHs), where such general relativistic effects as the
pericenter shift and gravitational wave (GW) emission are taken into
consideration. The attention is concentrated on the effects of the dynamical
friction and the Hoyle-Lyttleton mass accretion by ambient gas. We consider a
system composed of ten BHs with initial mass of $30~M_\odot$. As a result, we
show that mergers of accreting stellar-mass BHs are classified into four types:
a gas drag-driven, an interplay-driven, a three body-driven, or an
accretion-driven merger. We find that BH mergers proceed before significant
mass accretion, even if the accretion rate is $\sim10$ Eddington accretion
rate, and then all BHs can merge into one heavy BH. Using the simulation
results for a wide range of parameters, we derive a critical accretion rate
($\dot{m}_{\rm c}$), below which the BH growth is promoted faster by mergers.
Also, it is found that the effect of the recoil by the GW emission can reduce
$\dot{m}_{\rm c}$ especially in gas number density higher than $10^8~{\rm
cm}^{-3}$, and enhance the escape probability of merged BHs. Very recently, a
gravitational wave event, GW150914, as a result of the merger of a $\sim
30~M_\odot$ BH binary has been detected (Abbott et al. 2016). Based on the
present simulations, the BH merger in GW150914 is likely to be driven by
three-body encounters accompanied by a few $M_\odot$ of gas accretion, in
high-density environments like dense interstellar clouds or galactic nuclei.


title: The $L^2$-Alexander torsion for Seifert fiber spaces

abstract:
  We calculate the $L^2$-Alexander torsion for Seifert fiber spaces and graph
manifolds in terms of the Thurston norm.


title: Geared topological metamaterials with tunable mechanical stability

abstract:
  The classification of materials into insulators and conductors has been
shaken up by the discovery of topological insulators that conduct robustly at
the edge but not in the bulk. In mechanics, designating a material as
insulating or conducting amounts to asking if it is rigid or floppy. Although
mechanical structures that display topological floppy modes have been proposed,
they are all vulnerable to global collapse. Here, we design and build
mechanical metamaterials that are stable and yet capable of harboring protected
edge and bulk modes, analogous to those in electronic topological insulators
and Weyl semimetals. To do so, we exploit gear assemblies that, unlike point
masses connected by springs, incorporate both translational and rotational
degrees of freedom. Global structural stability is achieved by eliminating
geometrical frustration of collective gear rotations extending through the
assembly. The topological robustness of the mechanical modes makes them
appealing across scales from engineered macrostructures to networks of toothed
microrotors of potential use in micro-machines.


title: New Statistical Perspective to The Cosmic Void Distribution

abstract:
  In this study, we obtain the size distribution of voids as a 3-parameter
redshift independent log-normal void probability function (VPF) directly from
the Cosmic Void Catalog (CVC). Although many statistical models of void
distributions are based on the counts in randomly placed cells, the log-normal
VPF that we here obtain is independent of the shape of the voids due to the
parameter-free void finder of the CVC. We use three void populations drawn from
the CVC generated by the Halo Occupation Distribution (HOD) Mocks which are
tuned to three mock SDSS samples to investigate the void distribution
statistically and the effects of the environments on the size distribution. As
a result, it is shown that void size distributions obtained from the HOD Mock
samples are satisfied by the 3-parameter log-normal distribution. In addition,
we find that there may be a relation between hierarchical formation, skewness
and kurtosis of the log-normal distribution for each catalog. We also show that
the shape of the 3-parameter distribution from the samples is strikingly
similar to the galaxy log-normal mass distribution obtained from numerical
studies. This similarity of void size and galaxy mass distributions may
possibly indicate evidence of nonlinear mechanisms affecting both voids and
galaxies, such as large scale accretion and tidal effects. Considering in this
study all voids are generated by galaxy mocks and show hierarchical structures
in different levels, it may be possible that the same nonlinear mechanisms of
mass distribution affect the void size distribution.


title: Investigating practical linear temporal difference learning

abstract:
  Off-policy reinforcement learning has many applications including: learning
from demonstration, learning multiple goal seeking policies in parallel, and
representing predictive knowledge. Recently there has been an proliferation of
new policy-evaluation algorithms that fill a longstanding algorithmic void in
reinforcement learning: combining robustness to off-policy sampling, function
approximation, linear complexity, and temporal difference (TD) updates. This
paper contains two main contributions. First, we derive two new hybrid TD
policy-evaluation algorithms, which fill a gap in this collection of
algorithms. Second, we perform an empirical comparison to elicit which of these
new linear TD methods should be preferred in different situations, and make
concrete suggestions about practical use.


title:
Search for supersymmetry in electroweak production with photons and
  large missing transverse energy in pp collisions at sqrt(s) = 8 TeV

abstract:
  Results are reported from a search for supersymmetry with gauge-mediated
supersymmetry breaking in electroweak production. Final states with photons and
large missing transverse energy (MET) were examined. The data sample was
collected in pp collisions at sqrt(s) = 8 TeV with the CMS detector at the LHC
and corresponds to 7.4 inverse femtobarns. The analysis focuses on scenarios in
which the lightest neutralino has bino- or wino-like components, resulting in
decays to photons and gravitinos, where the gravitinos escape undetected. The
data were obtained using a specially designed trigger with dedicated low
thresholds, providing good sensitivity to signatures with photons, MET, and low
hadronic energy. No excess of events over the standard model expectation is
observed. The results are interpreted using the model of general gauge
mediation. With the wino mass fixed at 10 GeV above that of the bino, wino
masses below 710 GeV are excluded at 95% confidence level. Constraints are also
set in the context of two simplified models, for which the analysis sets the
lowest cross section limits on the electroweak production of supersymmetric
particles.


title:
Macro vs. Micro Methods in Non-Life Claims Reserving (an Econometric
  Perspective)

abstract:
  Traditionally, actuaries have used run-off triangles to estimate reserve
("macro" models, on agregated data). But it is possible to model payments
related to individual claims. If those models provide similar estimations, we
investigate uncertainty related to reserves, with "macro" and "micro" models.
We study theoretical properties of econometric models (Gaussian, Poisson and
quasi-Poisson) on individual data, and clustered data. Finally, application on
claims reserving are considered.


title: Many Correlation Tables are Molien Sequences

abstract:
  Using the Jordan-Schwinger form of the quantum angular momentum eigenstates,
it is straight-forward to define rotational correlation tables such that the
columns are Molien sequences for finite rotational subgroup $G$. This
realization gives a new and better means of calculation. Generalization to
unitary symmetry $U(n)$ implies many more sequences, which determine degeneracy
observables in the context of electronic, vibrational, and rotational motion.
This leads us to discuss one physical significance of the Hilbert finite basis
theorem.


title:
Categorization of Mechanics Problems by Students in Large Introductory
  Physics Courses: A Comparison with the Chi, Feltovich, and Glaser Study

abstract:
  With inspiration from the classic study by Chi, Feltovich, and Glaser [1], we
asked introductory physics students in three introductory physics classes to
categorize mechanics problems based upon similarity of solutions. To evaluate
the effect of problem context on students' ability to categorize, two sets of
problems were developed for categorization. Some problems in one of the problem
sets that students were asked to categorize included those available from the
prior study by Chi et al. Our findings, which contrast from those of Chi et
al., suggest that there is a much wider distribution of expertise among
introductory students.


title: Identification of simple reaction coordinates from complex dynamics

abstract:
  Reaction coordinates are widely used throughout chemical physics to model and
understand complex chemical transformations. We introduce a definition of the
natural reaction coordinate, suitable for condensed phase and biomolecular
systems, as a maximally predictive one-dimensional projection. We then show
this criterion is uniquely satisfied by a dominant eigenfunction of an integral
operator associated with the ensemble dynamics. We present a new sparse
estimator for these eigenfunctions which can search through a large candidate
pool of structural order parameters and build simple, interpretable
approximations that employ only a small number of these order parameters.
Example applications with a small molecule's rotational dynamics and
simulations of protein conformational change and folding show that this
approach can filter through statistical noise to identify simple reaction
coordinates from complex dynamics.


title:
On Perception and Reality in Wireless Air Traffic Communications
  Security

abstract:
  More than a dozen wireless technologies are used by air traffic communication
systems during different flight phases. From a conceptual perspective, all of
them are insecure as security was never part of their design. Recent
contributions from academic and hacking communities have exploited this
inherent vulnerability to demonstrate attacks on some of these technologies.
However, not all of these contributions have resonated widely within aviation
circles. At the same time, the security community lacks certain aviation domain
knowledge, preventing aviation authorities from giving credence to their
findings.
  In this paper, we aim to reconcile the view of the security community and the
perspective of aviation professionals concerning the safety of air traffic
communication technologies. To achieve this, we first provide a systematization
of the applications of wireless technologies upon which civil aviation relies.
Based on these applications, we comprehensively analyze vulnerabilities,
attacks, and countermeasures. We categorize the existing research on
countermeasures into approaches that are applicable in the short term and
research of secure new technologies deployable in the long term.
  Since not all of the required aviation knowledge is codified in academic
publications, we additionally examine existing aviation standards and survey
242 international aviation experts. Besides their domain knowledge, we also
analyze the awareness of members of the aviation community concerning the
security of wireless systems and collect their expert opinions on the potential
impact of concrete attack scenarios using these technologies.


title: Proving completeness of logic programs with the cut

abstract:
  Completeness of a logic program means that the program produces all the
answers required by its specification. The cut is an important construct of
programming language Prolog. It prunes part of the search space, this may
result in a loss of completeness. This paper proposes a way of proving
completeness of programs with the cut. The semantics of the cut is formalized
by describing how SLD-trees are pruned. A sufficient condition for completeness
is presented, proved sound, and illustrated by examples.


title: Black hole with a scalar field as a particle accelerator

abstract:
  We consider stationary axially symmetric black holes with the background
scalar field and test particles that can interact with this field directly.
Then, particle collision near a black hole can lead to the unbounded energy $%
E_{c.m.}$ in the centre of mass frame (contrary to some recent claims in
literature). This happens always if one of particles is neutral whereas another
one has nonzero scalar charge. Kinematically, two cases occur here. (i) A
neutral particle approaches the horizon with the speed of light while the
velocity of the charged one remains separated from it (this is direct analogue
of the situation with collision of geodesic particles.). (ii) Both particles
approach the horizon with the speed almost equal to that of light but with
different rates. As a result, in both cases the relative velocity also
approaches the speed of light, so that $E_{c.m.}$ $\ $becomes unbounded. We
consider also a case when the metric coefficient $g_{\phi \phi }\rightarrow 0$
near a black hole. Then, overlap between the geometric factor and the presence
of the scalar field opens additional scenarios in which unbounded energy
$E_{c.m.}$ is possible as well. We give a full list of possible scenarios of
high-energy collisions for the situations considered.


title: Does quantification without adjustments work?

abstract:
  Classification is the task of predicting the class labels of objects based on
the observation of their features. In contrast, quantification has been defined
as the task of determining the prevalences of the different sorts of class
labels in a target dataset. The simplest approach to quantification is Classify
& Count where a classifier is optimised for classification on a training set
and applied to the target dataset for the prediction of class labels. In the
case of binary quantification, the number of predicted positive labels is then
used as an estimate of the prevalence of the positive class in the target
dataset. Since the performance of Classify & Count for quantification is known
to be inferior its results typically are subject to adjustments. However, some
researchers recently have suggested that Classify & Count might actually work
without adjustments if it is based on a classifer that was specifically trained
for quantification. We discuss the theoretical foundation for this claim and
explore its potential and limitations with a numerical example based on the
binormal model with equal variances. In order to identify an optimal quantifier
in the binormal setting, we introduce the concept of local Bayes optimality. As
a side remark, we present a complete proof of a theorem by Ye et al. (2012).


title: Assessing Expertise in Introductory Physics Using Categorization Task

abstract:
  The ability to categorize problems based upon underlying principles, rather
than surface features or contexts, is considered one of several proxy
predictors of expertise in problem solving. With inspiration from the classic
study by Chi, Feltovich, and Glaser, we assess the distribution of expertise
among introductory physics students by asking three introductory physics
classes, each with more than a hundred students, to categorize mechanics
problems based upon similarity of solution. We compare their categorization
with those of physics graduate students and faculty members. To evaluate the
effect of problem context on students' ability to categorize, two sets of
problems were developed for categorization. Some problems in one set included
those available from the prior study by Chi et al. We find a large overlap
between calculus-based introductory students and graduate students with regard
to their categorizations that were assessed as "good." Our findings, which
contrast with those of Chi et al., suggest that there is a wide distribution of
expertise in mechanics among introductory and graduate students. Although the
categorization task is conceptual, introductory students in the calculus-based
course performed better than those in the algebra-based course. Qualitative
trends in categorization of problems are similar between the non-Chi problems
and problems available from the Chi study used in our study although the Chi
problems used are more difficult on average.


abstract:
  We establish a so-called counting lemma that allows embeddings of certain
linear uniform hypergraphs into sparse pseudorandom hypergraphs, generalizing a
result for graphs [Embedding graphs with bounded degree in sparse pseudorandom
graphs, Israel J. Math. 139 (2004), 93-137]. Applications of our result are
presented in the companion paper [Counting results for sparse pseudorandom
hypergraphs II].


title:
Rectangular Tantalum Carbide Halides TaCX (X = Cl, Br, I) monolayer:
  Novel Large-Gap Quantum Spin Hall Insulator

abstract:
  Quantum spin Hall (QSH) insulators possess edge states that are topologically
protected from backscattering. However, known QSH materials (e.g. HgTe/CdTe and
InAs/GaSb quantum wells) exhibit very small energy gap and only work at low
temperature, hindering their applications for room temperature devices. Based
on the first-principles calculations, we predict a novel family of QSH
insulators in monolayer tantalum carbide halide TaCX (X = Cl, Br, and I) with
unique rectangular lattice and large direct energy gaps larger than 0.2 eV,
accurately, 0.23$-$0.36 eV. The mechanism for 2D QSH effect in this system
originates from a intrinsic d$-$d band inversion, different from conventional
QSH systems with band inversion between s$-$p or p$-$p orbitals. Further, stain
and intrinsic electric field can be used to tune the electronic structure and
enhance the energy gap. TaCX nanoribbon, which has single-Dirac-cone edge
states crossing the bulk band gap, exhibits a linear dispersion with a high
Fermi velocity comparable to that of graphene. These 2D materials with
considerable nontrivial gaps promise great application potential in the new
generation of dissipationless electronics and spintronics.


title: Counting results for sparse pseudorandom hypergraphs II

abstract:
  We present a variant of a universality result of R\"odl [On universality of
graphs with uniformly distributed edges, Discrete Math. 59 (1986), no. 1-2,
125-134] for sparse, $3$-uniform hypergraphs contained in strongly jumbled
hypergraphs. One of the ingredients of our proof is a counting lemma for fixed
hypergraphs in sparse ``pseudorandom'' uniform hypergraphs, which is proved in
the companion paper [Counting results for sparse pseudorandom hypergraphs I].


title:
The Lyddane-Sachs-Teller relationship for polar vibrations in materials
  with monoclinic and triclinic crystal systems

abstract:
  A generalization of the Lyddane-Sachs-Teller relation is presented for polar
vibrations in materials with monoclinic and triclinic crystal systems. The
generalization is derived from an eigen displacement vector summation approach,
which is equivalent to the microscopic Born-Huang description of polar lattice
vibrations. An expression for a general oscillator strength is also described
for materials with monoclinic and triclinic crystal systems. A generalized
factorized dielectric response function characteristic for monoclinic and
triclinic materials is proposed. The generalized Lyddane-Sachs-Teller relation
is found valid for monoclinic $\beta$-Ga$_2$O$_3$, where accurate experimental
data became available recently from a comprehensive generalized ellipsometry
investigation. Data for triclinic crystal systems can be measured by
generalized ellipsometry as well, and are anticipated to become available soon
and results can be compared with the generalized relations presented here


title:
Canonical factorization of the quotient morphism for an affine
  $\mathbb{G}_a$-variety

abstract:
  Working over a ground field of characteristic zero, this paper studies the
quotient morphism $\pi :X\to Y$ for an affine $\mathbb{G}_a$-variety $X$ with
affine quotient $Y$. It is shown that the degree modules associated to the
$\mathbb{G}_a$-action give a uniquely determined sequence of dominant
$\mathbb{G}_a$-equivariant morphisms, $X=X_r\to X_{r-1}\to\cdots\to X_1\to
X_0=Y$, where $X_i$ is an affine $\mathbb{G}_a$-variety and $X_{i+1}\to X_i$ is
birational for each $i\ge 1$. This is the canonical factorization of $\pi$. We
give an algorithm for finding the degree modules associated to the given
$\mathbb{G}_a$-action, and this yields the canonical factorization of the
quotient morphism. The algorithm is applied to compute the canonical
factorization for several examples, including the homogeneous $(2,5)$-action on
$\mathbb{A}^3$. By a fundamental result of Kaliman and Zaidenberg, any
birational morphism of affine varieties is an affine modification, and each
mapping in these examples is presented as a $\mathbb{G}_a$-equivariant affine
modification.


title:
Maximum Pseudolikelihood Estimation for Model-Based Clustering of Time
  Series Data

abstract:
  Mixture of autoregressions (MoAR) models provide a model-based approach to
the clustering of time series data. The maximum likelihood (ML) estimation of
MoAR models requires the evaluation of products of large numbers of densities
of normal random variables. In practical scenarios, these products converge to
zero as the length of the time series increases, and thus the ML estimation of
MoAR models becomes infeasible without the use of numerical tricks. We propose
a maximum pseudolikelihood (MPL) estimation approach as an alternative to the
use of numerical tricks. The MPL estimator is proved to be consistent and can
be computed via an EM (expectation--maximization) algorithm. Simulations are
used to assess the performance of the MPL estimator against that of the ML
estimator in cases where the latter was able to be calculated. An application
to the clustering of time series data arising from a resting-state fMRI
experiment is presented as a demonstration of the methodology.


title:
Adams-Spanne type estimates for parabolic sublinear operators and their
  commutators by with rough kernels on parabolic generalized Morrey spaces

abstract:
  The aim of this paper is to give Adams-Spanne type estimates for parabolic
sublinear operators and their commutators by with rough kernels generated by
parabolic fractional integral operators under generic size conditions which are
satisfied by most of the operators in harmonic analysis. Their endpoint
estimates are also disposed.


title:
On equality of Hausdorff and affinity dimensions, via self-affine
  measures on positive subsystems

abstract:
  Under mild conditions we show that the affinity dimension of a planar
self-affine set is equal to the supremum of the Lyapunov dimensions of
self-affine measures supported on self-affine proper subsets of the original
set. These self-affine subsets may be chosen so as to have stronger separation
properties and in such a way that the linear parts of their affinities are
positive matrices. Combining this result with some recent breakthroughs in the
study of self-affine measures and their associated Furstenberg measures, we
obtain new criteria under which the Hausdorff dimension of a self-affine set
equals its affinity dimension. For example, applying recent results of
B\'{a}r\'{a}ny, Hochman-Solomyak and Rapaport, we provide new explicit examples
of self-affine sets whose Hausdorff dimension equals its affinity dimension,
and for which the linear parts do not satisfy any domination assumptions.


title: Product operators on mixed norm spaces

abstract:
  Inequalities for product operators on mixed norm Lebesgue spaces and permuted
mixed norm Lebesgue spaces are established. They depend only on inequalities
for the factors and on the Lebesgue indices involved. Inequalities for the
bivariate Laplace transform are given to illustrate the method. Also, an
elementary proof is presented for an $n$-variable Young's inequality in mixed
norm spaces.


title: The BigDAWG Architecture

abstract:
  BigDAWG is a polystore system designed to work on complex problems that
naturally span across different processing or storage engines. BigDAWG provides
an architecture that supports diverse database systems working with different
data models, support for the competing notions of location transparency and
semantic completeness via islands of information and a middleware that provides
a uniform multi-island interface. In this article, we describe the current
architecture of BigDAWG, its application on the MIMIC II medical dataset, and
our plans for the mechanics of cross-system queries. During the presentation,
we will also deliver a brief demonstration of the current version of BigDAWG.


title: Fermionic formula for double Kostka polynomials

abstract:
  The $X=M$ conjecture asserts that the $1D$ sum and the fermionic formula
coincide up to some constant power. In the case of type $A,$ both the $1D$ sum
and the fermionic formula are closely related to Kostka polynomials. Double
Kostka polynomials $K_{\Bla,\Bmu}(t),$ indexed by two double partitions
$\Bla,\Bmu,$ are polynomials in $t$ introduced as a generalization of Kostka
polynomials. In the present paper, we consider $K_{\Bla,\Bmu}(t)$ in the
special case where $\Bmu=(-,\mu'').$ We formulate a $1D$ sum and a fermionic
formula for $K_{\Bla,\Bmu}(t),$ as a generalization of the case of ordinary
Kostka polynomials. Then we prove an analogue of the $X=M$ conjecture.


title: Inference in Functional Linear Quantile Regression

abstract:
  In this paper, we study statistical inference in functional quantile
regression for scalar response and a functional covariate. Specifically, we
consider a functional linear quantile regression model where the effect of the
covariate on the quantile of the response is modeled through the inner product
between the functional covariate and an unknown smooth regression parameter
function that varies with the level of quantile. The objective is to test that
the regression parameter is constant across several quantile levels of
interest. The parameter function is estimated by combining ideas from
functional principal component analysis and quantile regression. An adjusted
Wald testing procedure is proposed for this hypothesis of interest, and its
chi-square asymptotic null distribution is derived. The testing procedure is
investigated numerically in simulations involving sparse and noisy functional
covariates and in a capital bike share data application. The proposed approach
is easy to implement and the {\tt R} code is published online at
\url{https://github.com/xylimeng/fQR-testing}.


title: A new error bound for linear complementarity problems for B-matrices

abstract:
  A new error bound for the linear complementarity problem is given when the
involved matrix is a B-matrix. It is shown that this bound is sharper than some
previous bounds [C.Q. Li, Y.T. Li. Note on error bounds for linear
complementarity problems for B-matrices, Applied Mathematics Letters,
57:108-113,2016] and [C.Q. Li, Y.T. Li. Weakly chained diagonally dominant
B-matrices and error bounds for linear complementarity problems, to appear in
Numer.Algor.].


title:
Submillimeter Atmospheric Transparency at Maunakea, at the South Pole,
  and at Chajnantor

abstract:
  For a systematic assessment of submillimeter observing conditions at
different sites, we constructed tipping radiometers to measure the broad band
atmospheric transparency in the window around 350 $\mu$m wavelength. The
tippers were deployed on Maunakea, Hawaii, at the South Pole, and in the
vicinity of Cerro Chajnantor in northern Chile. Identical instruments permit
direct comparison of these sites. Observing conditions at the South Pole and in
the Chajnantor area are better than on Maunakea. Simultaneous measurements with
two tippers demonstrate conditions at the summit of Cerro Chajnantor are
significantly better than on the Chajnantor plateau.


title: Quadratic covariations for the solution to a stochastic heat equation

abstract:
  Let $u(t,x)$ be the solution to a stochastic heat equation $$
\frac{\partial}{\partial t}u=\frac12\frac{\partial^2}{\partial
x^2}u+\frac{\partial^2}{\partial t\partial x}X(t,x),\quad t\geq 0, x\in
{\mathbb R} $$ with initial condition $u(0,x)\equiv 0$, where $X$ is a
time-space white noise. This paper is an attempt to study stochastic analysis
questions of the solution $u(t,x)$. In fact, the solution is a Gaussian process
such that the process $t\mapsto u(t,\cdot)$ is a bi-fractional Brownian motion
seemed a fractional Brownian motion with Hurst index $H=\frac14$ for every real
number $x$. However, the properties of the process $x\mapsto u(\cdot,x)$ are
unknown. In this paper we consider the quadratic covariations of the two
processes $x\mapsto u(\cdot,x),t\mapsto u(t,\cdot)$. We show that $x\mapsto
u(\cdot,x)$ admits a nontrivial finite quadratic variation and the forward
integral of some adapted processes with respect to it coincides with "It\^o's
integral", but it is not a semimartingale. Moreover, some generalized It\^o's
formulas and Bouleau-Yor identities are introduced.


title:
Transport anomalies and quantum criticality in electron-doped cuprate
  superconductors

abstract:
  Superconductivity research is like running a marathon. Three decades after
the discovery of high-Tc cuprates, there have been mass data generated from
transport measurements, which bring fruitful information. In this review, we
give a brief summary of the intriguing phenomena reported in electron-doped
cuprates from the aspect of electrical transport as well as the complementary
thermal transport. We attempt to sort out common features of the electron-doped
family, e.g. the strange metal, negative magnetoresistance, multiple sign
reversals of Hall in mixed state, abnormal Nernst signal, complex quantum
criticality. Most of them have been challenging the existing theories,
nevertheless, a unified diagram certainly helps to approach the nature of
electron-doped cuprates.


title: On the $\eta$-inverted sphere

abstract:
  It is shown that the first and second homotopy groups of the $\eta$-inverted
sphere spectrum over a field of characteristic not two are zero. A cell
presentation of higher Witt theory is given as well, at least over the complex
numbers.


title: Complementary Skyrmion Racetrack Memory with Voltage Manipulation

abstract:
  Magnetic skyrmion holds promise as information carriers in the
next-generation memory and logic devices, owing to the topological stability,
small size and extremely low current needed to drive it. One of the most
potential applications of skyrmion is to design racetrack memory (RM), named
Sk-RM, instead of utilizing domain wall (DW). However, current studies face
some key design challenges, e.g., skyrmion manipulation, data representation
and synchronization etc. To address these challenges, we propose here a
complementary Sk-RM structure with voltage manipulation. Functionality and
performance of the proposed design are investigated with micromagnetic
simulations.


title:
Iterative Aggregation Method for Solving Principal Component Analysis
  Problems

abstract:
  Motivated by the previously developed multilevel aggregation method for
solving structural analysis problems a novel two-level aggregation approach for
efficient iterative solution of Principal Component Analysis (PCA) problems is
proposed. The course aggregation model of the original covariance matrix is
used in the iterative solution of the eigenvalue problem by a power iterations
method. The method is tested on several data sets consisting of large number of
text documents.


title: An integral functional driven by fractional Brownian motion

abstract:
  Let $B^H$ be a fractional Brownian motion with Hurst index $0<H<1$ and the
weighted local time ${\mathscr L}^H(\cdot,t)$. In this paper, we consider the
integral functional $$ {\mathcal C}^H_t(a):=\lim_{\varepsilon\downarrow
0}\int_0^t1_{\{|B^H_s-a|>\varepsilon\}}\frac1{B^H_s-a}ds^{2H}\equiv
\frac1{\pi}{\mathscr H}{\mathscr L}^H(\cdot,t)(a) $$ in $L^2(\Omega)$ with $
a\in {\mathbb R}, t\geq 0$ and ${\mathscr H}$ denoting the Hilbert transform.
We show that $$ {\mathcal
C}^H_t(a)=2\left((B^H_t-a)\log|B^H_t-a|-B^H_t+a\log|a|
-\int_0^t\log|B^H_s-a|\delta B^H_s\right) $$ for all $a\in {\mathbb R}, t\geq
0$ which is the fractional version of Yamada's formula, where the integral is
the Skorohod integral. Moreover, we introduce the following {\it occupation
type formula}: $$ \int_{\mathbb R}{\mathcal
C}^H_t(a)g(a)da=2H\pi\int_0^t({\mathscr H}g)(B^H_s)s^{2H-1}ds $$ for all
continuous functions $g$ with compact support.


title: Exploring the coevolution of predator and prey morphology and behavior

abstract:
  A common idiom in biology education states, "Eyes in the front, the animal
hunts. Eyes on the side, the animal hides." In this paper, we explore one
possible explanation for why predators tend to have forward-facing, high-acuity
visual systems. We do so using an agent-based computational model of evolution,
where predators and prey interact and adapt their behavior and morphology to
one another over successive generations of evolution. In this model, we observe
a coevolutionary cycle between prey swarming behavior and the predator's visual
system, where the predator and prey continually adapt their visual system and
behavior, respectively, over evolutionary time in reaction to one another due
to the well-known "predator confusion effect." Furthermore, we provide evidence
that the predator visual system is what drives this coevolutionary cycle, and
suggest that the cycle could be closed if the predator evolves a hybrid visual
system capable of narrow, high-acuity vision for tracking prey as well as
broad, coarse vision for prey discovery. Thus, the conflicting demands imposed
on a predator's visual system by the predator confusion effect could have led
to the evolution of complex eyes in many predators.


title: Hidden symmetries in jammed systems

abstract:
  There are deep, but hidden, geometric structures within jammed systems,
associated with hidden symmetries. These can be revealed by repeated
transformations under which these structures lead to fixed points. These
geometric structures can be found in the Voronoi tesselation of space defined
by the packing. In this paper we examine two iterative processes: maximum
inscribed sphere (MIS) inversion and a real-space coarsening scheme. Under
repeated iterations of the MIS inversion process we find invariant systems in
which every particle is equal to the maximum inscribed sphere within its
Voronoi cell. Using a real-space coarsening scheme we reveal behavior in
geometric order parameters which is length-scale invariant.


title:
Tackling tangledness of cosmic strings by knot polynomial topological
  invariants

abstract:
  Cosmic strings in the early universe have received revived interest in recent
years. In this paper we derive these structures as topological defects from
singular distributions of the quintessence field of dark energy. Our emphasis
is placed on the topological charge of tangled cosmic strings, which originates
from the Hopf mapping and is a Chern-Simons action possessing strong inherent
tie to knot topology. It is shown that the Kauffman bracket knot polynomial can
be constructed in terms of this charge for un-oriented knotted strings, serving
as a topological invariant much stronger than the traditional Gauss linking
numbers in characterizing string topology. Especially, we introduce a
mathematical approach of breaking-reconnection which provides a promising
candidate for studying physical reconnection processes within the
complexity-reducing cascades of tangled cosmic strings.


title:
Two-Scale Stochastic Control for Multipoint Communication Systems with
  Renewables

abstract:
  Increasing threats of global warming and climate changes call for an
energy-efficient and sustainable design of future wireless communication
systems. To this end, a novel two-scale stochastic control framework is put
forth for smart-grid powered coordinated multi-point (CoMP) systems. Taking
into account renewable energy sources (RES), dynamic pricing, two-way energy
trading facilities and imperfect energy storage devices, the energy management
task is formulated as an infinite-horizon optimization problem minimizing the
time-average energy transaction cost, subject to the users' quality of service
(QoS) requirements. Leveraging the Lyapunov optimization approach as well as
the stochastic subgradient method, a two-scale online control (TS-OC) approach
is developed for the resultant smart-grid powered CoMP systems. Using only
historical data, the proposed TS-OC makes online control decisions at two
timescales, and features a provably feasible and asymptotically near-optimal
solution. Numerical tests further corroborate the theoretical analysis, and
demonstrate the merits of the proposed approach.


title: Can $X(5568)$ be a tetraquark state?

abstract:
  Very recently, the D0 collaboration has reported the observation of a narrow
structure, $X(5568)$, in the decay process $X(5568)\to B^0_s\pi^\pm$ using the
10.4${\rm fb}^{-1}$ data of $p\bar p$ collision at $\sqrt s= 1.96$ TeV. This
structure is of great interest since it is the first hadronic state with four
different valence quark flavors, $b,s,u,d$. In this work, we investigate
tetraquarks with four different quark flavors. Based on the diquark-antidiquark
scheme, we study the spectroscopy of the tetraquarks with one heavy
bottom/charm quark and three light quarks. We find that the lowest-lying S-wave
state, a tetraquark with the flavor $[su][\bar b\bar d ]$ and the spin-parity
$J^P=0^+$, is about 150 MeV higher than the $X(5568)$. Further detailed
experimental and theoretical studies of the spectrum, production and decays of
tetraquark states with four different flavors in the future are severely needed
towards a better understanding its nature and the classification of hadron
exotic states.


title:
Exploratory data analysis for moderate extreme values using
  non-parametric kernel methods

abstract:
  In many settings it is critical to accurately model the extreme tail
behaviour of a random process. Non-parametric density estimation methods are
commonly implemented as exploratory data analysis techniques for this purpose
as they possess excellent visualisation properties, and can naturally avoid the
model specification biases implied by using parametric estimators. In
particular, kernel-based estimators place minimal assumptions on the data, and
provide improved visualisation over scatterplots and histograms. However kernel
density estimators are known to perform poorly when estimating extreme tail
behaviour, which is important when interest is in process behaviour above some
large threshold, and they can over-emphasise bumps in the density for heavy
tailed data. In this article we develop a transformation kernel density
estimator, and demonstrate that its mean integrated squared error (MISE)
efficiency is equivalent to that of standard, non-tail focused kernel density
estimators. Estimator performance is illustrated in numerical studies, and in
an expanded analysis of the ability of well known global climate models to
reproduce observed temperature extremes in Sydney, Australia.


title:
Critical behaviours of the fifth Painlev\'e transcendents and the
  monodromy data

abstract:
  For the fifth Painlev\'e equation, we present families of convergent series
solutions near the origin and the corresponding monodromy data for the
associated isomonodromy linear system. These solutions are of complex power
type, of inverse logarithmic type and of Taylor series type. It is also
possible to compute the monodromy data in non-generic cases. Solutions of
logarithmic type are derived from those of inverse logarithmic type through a
B\"{a}cklund transformation found by Gromak. In a special case the complex
power type of solutions have relatively simple oscillatory expressions. For the
complex power type of solutions in the generic case, we clarify the structure
of the analytic continuation on the universal covering around the origin, and
examine the distribution of zeros, poles and 1-points. It is shown that two
kinds of spiral domains including a sector as a special case are alternately
arrayed; the domains of one kind contain sequences both of zeros and of poles,
and those of the other kind sequences of 1-points.


title: Operators for Space and Time in BeSpaceD

abstract:
  In this report, we present some spatio-temporal operators for our BeSpaceD
framework. We port operators known from functional programming languages such
as filtering, folding and normalization on abstract data structures to the
BeSpaceD specification language. We present the general ideas behind the
operators, highlight implementation details and present some simple examples.


title: A Model-Based Scatter Artifacts Correction for Cone Beam CT

abstract:
  The purpose of this work is to provide a fast and accurate scatter artifacts
correction algorithm for cone beam CT (CBCT) imaging. The method starts with an
estimation of coarse scatter profiles for a set of CBCT data in either image
domain or projection domain. A denoising algorithm designed specifically for
Poisson signals is then applied to derive the final scatter distribution.
Qualitative and quantitative evaluations using thorax and abdomen phantoms with
Monte Carlo (MC) simulations, experimental Catphan phantom data, and in vivo
human data acquired for a clinical image guided radiation therapy were
performed. Results show that the proposed algorithm can significantly reduce
scatter artifacts and recover the correct HU in either projection domain or
image domain. For the MC thorax phantom study, four components segmentation
yield the best results, while the results of three components segmentation are
still acceptable. For the Catphan phantom data, the mean value over all pixels
in the residual image is reduced from -21.8 HU to -0.2 HU and 0.7 HU for
projection domain and image domain, respectively. The contrast of the in vivo
human images are greatly improved after correction. The software-based
technique has a number of advantages, such as high computational efficiency and
accuracy, and the capability of performing scatter correction without modifying
the clinical workflow or modifying the imaging hardware. When implemented
practically, this should improve the accuracy of CBCT image quantitation and
significantly impact CBCT-based interventional procedures and adaptive
radiation therapy.


title:
On the boundedness of Pseudo-differential operators on Triebel-Lizorkin
  and Besov spaces

abstract:
  In this work we show endpoint boundedness properties of pseudo-differential
operators of type $(\rho,\rho)$, $0<\rho<1$, on Triebel-Lizorkin and Besov
spaces. Our results are sharp and they also cover operators defined by compound
symbols.


title:
Galerkin Finite Element Approximations for Stochastic Space-Time
  Fractional Wave Equations

abstract:
  The traditional wave equation models wave propagation in an ideal conducting
medium. For characterizing the wave propagation in inhomogeneous media with
frequency dependent power-law attenuation, the space-time fractional wave
equation appears; further incorporating the additive white Gaussian noise
coming from many natural sources leads to the stochastic space-time fractional
wave equation. This paper discusses the Galerkin finite element approximations
for the stochastic space-time fractional wave equation forced by an additive
space-time white noise. We firstly discretize the space-time additive noise,
which introduces a modeling error and results in a regularized stochastic
space-time fractional wave equation; then the regularity of the regularized
equation is analyzed. For the discretization in space, the finite element
approximation is used and the definition of the discrete fractional Laplacian
is introduced. We derive the mean-squared $L^2$-norm priori estimates for the
modeling error and for the approximation error to the solution of the
regularized problem; and the numerical experiments are performed to confirm the
estimates. For the time-stepping, we calculate the analytically obtained
Mittag-Leffler type function.


title: Trust-Region Methods for Sparse Relaxation

abstract:
  In this paper, we solve the l2-l1 sparse recovery problem by transforming the
objective function of this problem into an unconstrained differentiable
function and apply a limited-memory trust-region method. Unlike gradient
projection-type methods, which uses only the current gradient, our approach
uses gradients from previous iterations to obtain a more accurate Hessian
approximation. Numerical experiments show that our proposed approach eliminates
spurious solutions more effectively while improving the computational time to
converge.


title:
Testing for uniformity of Ultra-High Energy Cosmic Ray arrival
  directions

abstract:
  Arrival directions of ultra-high energy cosmic rays (UHECRs) exhibit mainly
an isotropic distribution with some small deviations in particular energy bins.
In this paper, the Yakutsk array data are tested for circular uniformity of
arrival directions in right ascension using 2 methods appropriate for the
energy ranges below and above $10^{18}$ eV. No statistically significant
deviation from uniformity is found in the arrival directions of cosmic rays
(CRs) detected within the observation period 1974--2000.


title:
A Discrete Divergence-Free Weak Galerkin Finite Element Method for the
  Stokes Equations

abstract:
  A discrete divergence-free weak Galerkin finite element method is developed
for the Stokes equations based on a weak Galerkin (WG) method introduced in the
reference [15]. Discrete divergence-free bases are constructed explicitly for
the lowest order weak Galerkin elements in two and three dimensional spaces.
These basis functions can be derived on general meshes of arbitrary shape of
polygons and polyhedrons. With the divergence-free basis derived, the discrete
divergence-free WG scheme can eliminate the pressure variable from the system
and reduces a saddle point problem to a symmetric and positive definite system
with many fewer unknowns. Numerical results are presented to demonstrate the
robustness and accuracy of this discrete divergence-free WG method.


title: Asymmetric Dark Matter Bound State

abstract:
  We propose an interesting framework for asymmetric scalar dark matter (ADM),
which has novel collider phenomenology in terms of an unstable ADM bound state
(ADMonium) produced via Higgs portals. ADMonium is a natural consequence of the
basic features of ADM: the (complex scalar) ADM is charged under a dark local
$U(1)_d$ symmetry which is broken at a low scale and provides a light gauge
boson $X$. The dark gauge coupling is strong and then ADM can annihilate away
into $X$-pair effectively. Therefore, the ADM can form bound state due to its
large self-interaction via $X$ mediation. To explore the collider signature of
ADMonium, we propose that ADM has a two-Higgs doublet portal. The ADMonium can
have a sizable mixing with the heavier Higgs boson, which admits a large cross
section of ADMonium production associated with $b\bar b$. The resulting
signature at the LHC depends on the decays of $X$. In this paper we consider a
case of particular interest: $pp\ra b\bar b+ {\rm ADMonium}$ followed by ${\rm
ADMonium}\ra 2X\ra 2e^+e^-$ where the electrons are identified as (un)converted
photons. It may provide a competitive explanation to heavy di-photon resonance
searches at the LHC.


title:
Effective Implementation of the Weak Galerkin Finite Element Methods for
  the Biharmonic Equation

abstract:
  The weak Galerkin (WG) methods have been introduced in the references [11,
16] for solving the biharmonic equation. The purpose of this paper is to
develop an algorithm to implement the WG methods effectively. This can be
achieved by eliminating local unknowns to obtain a global system with
significant reduction of size. In fact, this reduced global system is
equivalent to the Schur complements of the WG methods. The unknowns of the
Schur complement of the WG method are those defined on the element boundaries.
The equivalence of the WG method and its Schur complement is established. The
numerical results demonstrate the effectiveness of this new implementation
technique.


title:
On the Measurement in Quantum Mechanics: the Consistent Measurement
  Apparatus

abstract:
  Measurement in quantum mechanics is generally described as an irreversible
process that perturbs the wavefunction describing a quantum system. In this
work we establish a formal connection between the measurement description
within the Copenhagen interpretation (i.e., through the collapse of the
wavefunction) compared versus a picture in which the system and the measurement
apparatus are considered as a whole. We first consider a projective
measurement. In this limiting case, the natural requirements of consistency and
equivalence between the two pictures lead to the rigorous definition of
consistent measuring apparatus: the orthonormal wavefunctions from the Schmidt
decomposition of the system plus apparatus must have non-overlapping supports.
This result arises from the comparison of the two pictures (otherwise hidden),
and while it seems to be an obvious conclusion in the limit of projective
measurements, it has some nontrivial implications as one extends its validity
to the domain of weak measurements. In this respect, we argue on the existence
of two alternative approaches to mathematically constructing a weak measurement
protocol. While the two approaches are equivalent from the system's
perspective, they do strongly differ from the apparatus point of view, and
hence can be only distinguished one from each other in the picture where system
and apparatus are considered as a whole. We show that only one of the two
mathematical formulations of the weak measurement fulfills the consistent
apparatus condition, while the combination of the two gives rise to a
generalized weak measurements framework.


title: Resonances from QCD bound states and the 750 GeV diphoton excess

abstract:
  Pair production of colored particles is in general accompanied by production
of QCD bound states (onia) slightly below the pair-production threshold. Bound
state annihilation leads to resonant signals, which in some cases are easier to
see than the decays of the pair-produced constituents. In a previous paper
(arXiv:1204.1119) we estimated the bound state signals, at leading order and in
the Coulomb approximation, for particles with various spins, color
representations and electric charges, and used 7 TeV ATLAS and CMS resonance
searches to set rough limits. Here we update our results to include 8 and 13
TeV data. We find that the recently reported diphoton excesses near 750 GeV
could indeed be due to a bound state of this kind. A narrow resonance of the
correct size could be obtained for a color-triplet scalar with electric charge
-4/3 and mass near 375 GeV, if (as a recent lattice computation suggests) the
wave function at the origin is somewhat larger than anticipated. Pair
production of this particle could have evaded detection up to now. Other
candidates may include a triplet scalar of charge 5/3, a triplet fermion of
charge -4/3, and perhaps a sextet scalar of charge -2/3.


title: Compressing Graphs and Indexes with Recursive Graph Bisection

abstract:
  Graph reordering is a powerful technique to increase the locality of the
representations of graphs, which can be helpful in several applications. We
study how the technique can be used to improve compression of graphs and
inverted indexes.
  We extend the recent theoretical model of Chierichetti et al. (KDD 2009) for
graph compression, and show how it can be employed for compression-friendly
reordering of social networks and web graphs and for assigning document
identifiers in inverted indexes. We design and implement a novel theoretically
sound reordering algorithm that is based on recursive graph bisection.
  Our experiments show a significant improvement of the compression rate of
graph and indexes over existing heuristics. The new method is relatively simple
and allows efficient parallel and distributed implementations, which is
demonstrated on graphs with billions of vertices and hundreds of billions of
edges.


title: Lagrangian isotopy of tori in $S^2 \times S^2$ and $\mathbb{C}P^2$

abstract:
  We show that, up to Lagrangian isotopy, there is a unique Lagrangian torus
inside each of the following uniruled symplectic four-manifolds: the symplectic
vector space $\mathbb{R}^4$, the projective plane $\mathbb{C}P^2$, and the
monotone $S^2 \times S^2$. The result is proven by studying pseudoholomorphic
foliations while performing the splitting construction from symplectic field
theory along the Lagrangian torus. A number of other related results are also
shown. Notably, the nearby Lagrangian conjecture is established for
$T^*\mathbb{T}^2$, i.e.~it is shown that every closed exact Lagrangian
submanifold in this cotangent bundle is Hamiltonian isotopic to the
zero-section.


title: Heavy Dirac fermions in a graphene/topological insulator hetero-junction

abstract:
  The low energy physics of both graphene and surface states of
three-dimensional topological insulators is described by gapless Dirac fermions
with linear dispersion. In this work, we predict the emergence of a "heavy"
Dirac fermion in a graphene/topological insulator hetero-junction, where the
linear term almost vanishes and the corresponding energy dispersion becomes
highly non-linear. By combining {\it ab initio} calculations and an effective
low-energy model, we show explicitly how strong hybridization between Dirac
fermions in graphene and the surface states of topological insulators can
reduce the Fermi velocity of Dirac fermions. Due to the negligible linear term,
interaction effects will be greatly enhanced and can drive "heavy" Dirac
fermion states into the half quantum Hall state with non-zero Hall conductance.


title:
Epitaxial growth of diluted magnetic semiconductor Ge1-xCrxTe with high
  Cr composition

abstract:
  IV-VI diluted magnetic semiconductor Ge1-xCrxTe layers up to x=0.1 were grown
on SrF2 substrates by molecular beam epitaxy. In site reflection high-energy
electron diffraction shows a streaky pattern with sixfold symmetry in the plane
for the Ge1-xCrxTe layer, implying an epitaxial growth of Ge1-xCrxTe [111]/SrF2
[111]. A clear hysteresis loop is observed in the anomalous Hall effect
measurements due to the strong spin-orbit interaction in the host GeTe. The
Curie temperature increases with increasing Cr composition up to 200 K, but
there is no clear dependence of the Curie temperature on the hole
concentration, implying that the mechanism of the ferromagnetic interaction
among Cr ions is different from Mn doped diluted magnetic semiconductors.


title:
Binary information propagation in circular magnetic nanodot arrays using
  strain induced magnetic anisotropy

abstract:
  Nanomagnetic logic has emerged as a potential replacement for traditional
CMOS-based logic because of superior energy-efficiency. One implementation of
nanomagnetic logic employs shape-anisotropic (e.g. elliptical) ferromagnets
(with two stable magnetization orientations) as binary switches that rely on
dipole-dipole interaction to communicate binary information. Normally, circular
nanomagnets are incompatible with this approach since they lack distinct stable
in-plane magnetization orientations to encode bits. However, circular
magnetoelastic nanomagnets can be made bi-stable with a voltage induced
anisotropic strain, which provides two significant advantages for nanomagnetic
logic applications. First, the shape anisotropy energy barrier is eliminated
which reduces the amount of energy to reorient the dipole. Second, the in-plane
size can be reduced (~20nm) which was previously impossible due to thermal
stability issues. In circular magnetoelastic nanomagnets, a voltage induced
strain stabilizes the magnetization even at this size overcoming the thermal
stability issue. In this paper, we analytically demonstrate a binary logic wire
implemented with an array of circular nanomagnets that are clocked with
voltage-induced strain applied by an underlying piezoelectric substrate. This
leads to an energy-efficient logic paradigm orders of magnitude superior to
existing CMOS-based logic that is scalable to dimensions substantially smaller
than those for existing nanomagnetic logic approaches. The analytical approach
is validated with experimental measurements conducted on dipole coupled Ni
nanodots fabricated on a PMN-PT sample.


title:
Differences in Halo-Scale Environments between Type 1 and Type 2 AGNs at
  Low Redshift

abstract:
  Using low-redshift (z<0.09) samples of AGNs, normal galaxies and groups of
galaxies selected from the Sloan Digital Sky Survey (SDSS), we study the
environments of type 1 and type 2 AGNs both on small and large scales.
Comparisons are made for galaxy samples matched in redshift, $r$-band
luminosity, [OIII] luminosity, and also the position in groups (central or
satellite). We find that type 2 AGNs and normal galaxies reside in similar
environments. Type 1 and type 2 AGNs have similar clustering properties on
large scales ($\gtrsim1$Mpc), but at scales smaller than 100 kpc, type 2s have
significant more neighbors than type 1s ($3.09\pm0.69$ times more for central
AGNs at $\lesssim30$kpc). These results suggest that type 1 and type 2 AGNs are
hosted by halos of similar masses, as is also seen directly from the mass
distributions of their host groups ($\sim10^{12}h^{-1} M_{\odot}$ for centrals
and $\sim10^{13}h^{-1} M_{\odot}$ for satellites). Type~2s have significantly
more satellites around them, and the distribution of their satellites is also
more centrally concentrated. The host galaxies of both types of AGNs have
similar optical properties, but their infrared colors are significantly
different. Our results suggest that the simple unified model based solely on
torus orientation is not sufficient, but that galaxy interactions in dark
matter halos must have played an important role in the formation of the dust
structure that obscures AGNs.


title:
Enhanced absorption in heterostructures with graphene and truncated
  photonic crystals

abstract:
  We theoretically and experimentally investigate the optical absorption
properties of heterostructures composed of graphene films and truncated
photonic crystals (PCs) in the visible range. The experimental results show
that the absorption of the heterostructure is enhanced greatly in the whole
forbidden gap of PCs compared with that of graphene alone. The absorption is
enhanced over a wide angle of incidence for both transverse electric (TE) and
transverse magnetic (TM) polarizations. The enhanced absorption band broadens
for TE polarization but narrows for TM polarization as the incident angle
increases. In the forbidden gap of the PCs, the maximum absorptance of the
heterostructures is nearly four times of that of bare graphene films for
arbitrary incident angles and polarizations. The optical experiments are in
excellent agreement with the theoretical results.


title:
An application of a theorem of Emerton to mod $p$ representations of
  $\mathrm{GL}_2$

abstract:
  Let $p$ be a prime and $L$ be a finite extension of $\mathbb{Q}_p$. We study
the ordinary parts of $\mathrm{GL}_2(L)$-representations arised in the mod $p$
cohomology of Shimura curves attached to indefinite division algebras which
splits at a finite place above $p$. The main tool of the proof is a theorem of
Emerton \cite{Em3}.


title: Rigorous RG algorithms and area laws for low energy eigenstates in 1D

abstract:
  One of the central challenges in the study of quantum many-body systems is
the complexity of simulating them on a classical computer. A recent advance of
Landau et al. gave a polynomial time algorithm to actually compute a succinct
classical description for unique ground states of gapped 1D quantum systems.
Despite this progress many questions remained unresolved, including whether
there exist rigorous efficient algorithms when the ground space is degenerate
(and poly($n$) dimensional), or for the poly($n$) lowest energy states for 1D
systems, or even whether such states admit succinct classical descriptions or
area laws.
  In this paper we give a new algorithm for finding low energy states for 1D
systems, based on a rigorously justified RG type transformation. In the process
we resolve some of the aforementioned open questions, including giving a
polynomial time algorithm for poly($n$) degenerate ground spaces and an
$n^{O(\log n)}$ algorithm for the poly($n$) lowest energy states for 1D systems
(under a mild density condition). We note that for these classes of systems the
existence of a succinct classical description and area laws were not rigorously
proved before this work. The algorithms are natural and efficient, and for the
case of finding unique ground states for frustration-free Hamiltonians the
running time is $\tilde{O}(nM(n))$, where $M(n)$ is the time required to
multiply two $n\times n$ matrices.


title: Access Time Tradeoffs in Archive Compression

abstract:
  Web archives, query and proxy logs, and so on, can all be very large and
highly repetitive; and are accessed only sporadically and partially, rather
than continually and holistically. This type of data is ideal for
compression-based archiving, provided that random-access to small fragments of
the original data can be achieved without needing to decompress everything. The
recent RLZ (relative Lempel Ziv) compression approach uses a semi-static model
extracted from the text to be compressed, together with a greedy factorization
of the whole text encoded using static integer codes. Here we demonstrate more
precisely than before the scenarios in which RLZ excels. We contrast RLZ with
alternatives based on block-based adaptive methods, including approaches that
"prime" the encoding for each block, and measure a range of implementation
options using both hard-disk (HDD) and solid-state disk (SSD) drives. For HDD,
the dominant factor affecting access speed is the compression rate achieved,
even when this involves larger dictionaries and larger blocks. When the data is
on SSD the same effects are present, but not as markedly, and more complex
trade-offs apply.


title:
Sensitivity of YAC to measure the light-component spectrum of primary
  cosmic rays at the "knee" energies

abstract:
  A new air-shower core-detector array (YAC : Yangbajing Air-shower
Core-detector array) has been developed to measure the primary cosmic-ray
composition at the "knee" energies in Tibet, China, focusing mainly on the
light components. The prototype experiment (YAC-I) consisting of 16 detectors
has been constructed and operated at Yangbajing (4300 m a.s.l.) in Tibet since
May 2009. YAC-I is installed in the Tibet-III AS array and operates together.
In this paper, we performed a Monte Carlo simulation to check the sensitivity
of YAC-I+Tibet-III array to the cosmic-ray light component of cosmic rays
around the knee energies, taking account of the observation conditions of
actual YAC-I+Tibet-III array. The selection of light component from others was
made by use of an artificial neural network (ANN). The simulation shows that
the light-component spectrum estimated by our methods can well reproduce the
input ones within 10\% error, and there will be about 30\% systematic errors
mostly induced by the primary and interaction models used. It is found that the
full-scale YAC and the Tibet-III array is powerful to study the cosmic-ray
composition, in particular, to obtain the energy spectra of protons and helium
nuclei around the knee energies.


title: Neutral versus charged defect patterns in curved crystals

abstract:
  Characterizing the complex spectrum of topological defects in ground states
of curved crystals is a long-standing problem with wide implications, from the
mathematical Thomson problem to diverse physical realizations, including
fullerenes and particle-coated droplets. While the excess number of
"topologically-charged" 5-fold disclinations in a closed, spherical crystal is
fixed, here, we study the elementary transition from defect-free, flat crystals
to curved-crystals possessing an excess of "charged" disclinations in their
bulk. Specifically, we consider the impact of topologically-neutral patterns of
defects -- in the form of multi-dislocation chains or "scars" stable for small
lattice spacing -- on the transition from neutral to charged ground-state
patterns of a crystalline cap bound to a spherical surface. Based on the
asymptotic theory of caps in continuum limit of vanishing lattice spacing, we
derive the morphological phase diagram of ground state defect patterns, spanned
by surface coverage of the sphere and forces at the cap edge. For the singular
limit of zero edge forces, we find that scars reduce (by half) the threshold
surface coverage for excess disclinations. Even more significant, scars flatten
the geometric dependence of excess disinclination number on Gaussian curvature,
leading to a transition between stable "charged" and "neutral" patterns that
is, instead, critically sensitive to the compressive vs. tensile nature of
boundary forces on the cap.


title: The geometric Hopf invariant and surgery theory

abstract:
  The first author's geometric Hopf invariant of a stable map
$F:\Sigma^{\infty}X \to \Sigma^{\infty}Y$ is a stable ${\mathbb
Z}_2$-equivariant map $h(F):\Sigma^{\infty}X \to \Sigma^{\infty}(Y \wedge Y)$
constructed by an explicit difference construction applied to $(F \wedge
F)\Delta_X - \Delta_Y F$. The stable ${\mathbb Z}_2$-equivariant homotopy class
of $h(F)$ is the primary obstruction to desuspending $F$ up to homotopy. The
explicit nature of the construction allows for a $\pi$-equivariant version of
$h(F)$ in the case of a $\pi$-equivariant $F$, with $\pi$ a discrete group. In
earlier joint work we applied the $\pi_1(N)$-equivariant geometric Hopf
invariant of the Umkehr map $F:\Sigma^{\infty}N^+ \to \Sigma^{\infty}T(\nu_f)$
of an immersion $f:M \to N$ to capture the double points of $f$ in ${\mathbb
Z}_2$-equivariant homotopy theory. In this manuscript we use the
$\pi$-equivariant geometric Hopf invariant $h(F)$ to unify all the previous
homotopy theoretic treatments of double points. Furthermore, $h(F)$ is combined
with the second author's algebraic surgery theory of chain complexes with
Poincar\'e duality to provide the homotopy theoretic foundations for
non-simply-connected geometric surgery. For an $n$-dimensional normal map
$(f,b):M \to X$ the $\pi_1(X)$-equivariant geometric Hopf invariant $h(F)$ of
the Umkehr map $F:\Sigma^{\infty}X^+ \to\Sigma^{\infty}M^+$ is shown to induce
the $\pi_1(X)$-equivariant quadratic structure $\psi_F$ on the chain complex
kernel $C$ of $(f,b)$. Previously $\psi_F$ had only been constructed using the
chain complex analogue of the functional Steenrod squares. The Wall surgery
obstruction $\sigma_*(f,b)=(C,\psi_F) \in L_n({\mathbb Z}[\pi_1(X)])$ is the
cobordism class of the corresponding $n$-dimensional quadratic Poincar\'e
complex $(C,\psi_F)$, as in the original theory.


title: Efficient shortcut techniques in evanescently coupled waveguides

abstract:
  Shortcut to Adiabatic Passage (SHAPE) technique, in the context of coherent
control of atomic systems has gained considerable attention in last few years.
It is primarily because of its ability to manipulate population among the
quantum states infinitely fast compared to the adiabatic processes. Two methods
in this regard have been explored rigorously, namely the transitionless quantum
driving and the Lewis-Reisenfeld invariant approach. We have applied these two
methods to realize SHAPE in adiabatic waveguide coupler. Waveguide couplers are
integral components of photonic circuits, primarily used as switching devices.
Our study shows that with appropriate engineering of the coupling coefficient
and propagation constants of the coupler it is possible to achieve efficient
and complete power switching. We also observed that the coupler length could be
reduced significantly without affecting the coupling efficiency of the system.


title: Characterization of maximum hands-off control

abstract:
  Maximum hands-off control aims to maximize the length of time over which zero
actuator values are applied to a system when executing specified control tasks.
To tackle such problems, recent literature has investigated optimal control
problems which penalize the size of the support of the control function and
thereby lead to desired sparsity properties. This article gives the exact set
of necessary conditions for a maximum hands-off optimal control problem using
an $L_0$-(semi)norm, and also provides sufficient conditions for the optimality
of such controls. Numerical example illustrates that adopting an $L_0$ cost
leads to a sparse control, whereas an $L_1$-relaxation in singular problems
leads to a non-sparse solution.


title:
Entanglement-assisted classical communication can simulate classical
  communication without causal order

abstract:
  Phenomena induced by the existence of entanglement, such as nonlocal
correlations, exhibit characteristic properties of quantum mechanics
distinguishing from classical theories. When entanglement is accompanied by
classical communication, it enhances the power of quantum operations jointly
performed by two spatially separated parties. Such a power has been analyzed by
the gap between the performances of joint quantum operations implementable by
local operations at each party connected by classical communication with and
without the assistance of entanglement. In this work, we present a new
formulation for joint quantum operations connected by classical communication
beyond special relativistic causal order but without entanglement and still
within quantum mechanics. Using the formulation, we show that entanglement
assisting classical communication necessary for implementing a class of joint
quantum operations called separable maps can be interpreted to simulate
"classical communication" not respecting causal order. Our results reveal a new
counter-intuitive aspect of entanglement related to spacetime.


title: Full-Duplex Cloud-RAN with Uplink/Downlink Remote Radio Head Association

abstract:
  This paper considers a cloud radio access network (C-RAN) where spatially
distributed remote radio heads (RRHs) communicate with a full-duplex user. In
order to reflect a realistic scenario, the uplink (UL) and downlink (DL) RRHs
are assumed to be equipped with multiple antennas and distributed according to
a Poisson point process. We consider all participate and nearest RRH
association schemes with distributed beamforming in the form of maximum ratio
combining/maximal ratio transmission (MRC/MRT) and zero-forcing/MRT(ZF/MRT)
processing. We derive analytical expressions useful to compare the average sum
rate among association schemes as a function of the number of RRHs antennas and
density of the UL and DL RRHs. Numerical results show that significant
performance improvements can be achieved by using the full-duplex mode as
compared to the half-duplex mode, while the choice of the beamforming design as
well as the RRH association scheme plays a critical role in determining the
full-duplex gains.


title: Elementary symmetric polynomials in Stanley--Reisner face ring

abstract:
  Let $P$ be a simple polytope of dimension $n$ with $m$ facets. In this paper
we pay our attention on those elementary symmetric polynomials in the
Stanley--Reisner face ring of $P$ and study how the decomposability of the
$n$-th elementary symmetric polynomial influences on the combinatorics of $P$
and the topology and geometry of toric spaces over $P$. We give algebraic
criterions of detecting the decomposability of $P$ and determining when $P$ is
$n$-colorable in terms of the $n$-th elementary symmetric polynomial. In
addition, we define the Stanley--Reisner {\em exterior} face ring
$\mathcal{E}(K_P)$ of $P$, which is non-commutative in the case of ${\Bbb Z}$
coefficients, where $K_P$ is the boundary complex of dual of $P$. Then we
obtain a criterion for the (real) Buchstaber invariant of $P$ to be $m-n$ in
terms of the $n$-th elementary symmetric polynomial in $\mathcal{E}(K_P)$. Our
results as above can directly associate with the topology and geometry of toric
spaces over $P$. In particular, we show that the decomposability of the $n$-th
elementary symmetric polynomial in $\mathcal{E}(K_P)$ with ${\Bbb Z}$
coefficients can detect the existence of the almost complex structures of
quasitoric manifolds over $P$, and if the (real) Buchstaber invariant of $P$ is
$m-n$, then there exists an essential relation between the $n$-th equivariant
characteristic class of the (real) moment-angle manifold over $P$ in
$\mathcal{E}(K_P)$ and the characteristic functions of $P$.


title: The Fu-Yau equation with negative slope parameter

abstract:
  The Fu-Yau equation is an equation introduced by J. Fu and S.T. Yau as a
generalization to arbitrary dimensions of an ansatz for the Strominger system.
As in the Strominger system, it depends on a slope parameter $\alpha'$. The
equation was solved in dimension $2$ by Fu and Yau in two successive papers for
$\alpha'>0$, and for $\alpha'<0$. In the present paper, we solve the Fu-Yau
equation in arbitrary dimension for $\alpha'<0$. To our knowledge, these are
the first non-trivial solutions of the Fu-Yau equation in any dimension
strictly greater than $2$.


title:
C^1-Classification of gapped parent Hamiltonians of quantum spin chains
  with local symmetry

abstract:
  We consider the family of gapped Hamiltonians introduced in [FNW] on the
quantum spin chains $\bigotimes_{\mathbb Z}\mathop{\mathrm{M}}\nolimits_n$,
with local symmetry given by a group $G$. The $G$-symmetric gapped Hamiltonians
are given by triples $(k,u,V)$, where $u$ is a projective unitary
representation of $G$ on a finite dimensional space ${\mathbb C}^k$, and $V$ is
an isometry from ${\mathbb C}^k$ to ${\mathbb C}^n\otimes {\mathbb C}^k$. We
show that Hamiltonians $H_0,H_1$, given by the triples
  $(k^{(0)}, u^{(0)}, V^{(0)})$ and $(k^{(1)}, u^{(1)}, V^{(1)})$ are
$C^1$-equivalent if the projective representations $u^{(0)}$ and $u^{(1)}$ are
unitary equivalent.


title:
Dynamo model for grand maxima of solar activity: can superflares occur
  on the Sun?

abstract:
  Recent data on superflares on sun-like stars and radiocarbon data on solar
activity in the past are both indicative of transient epochs of unusually high
magnetic activity. We propose an explanation for the grand activity maxima in
the framework of a solar dynamo model with fluctuating parameters. Solar-type
dynamos are oscillatory because of the combination of the solar-type
differential rotation with positive (in the Northern hemisphere) alpha-effect.
An artificial reversal of the sign in the alpha-effect changes the dynamo to a
steady regime with hundreds of times larger magnetic energy compared to the
amplitude of the cyclic dynamo. Sufficiently large and durable fluctuations
reversing the sign of the alpha-effect during the growth phase of a magnetic
cycle can, therefore, cause a transient change to a steady dynamo with
considerably increased magnetic energy. This qualitative scenario for grand
activity maxima is supported by computations of the dynamo model with a
fluctuating alpha-effect. The computed statistics of several thousand magnetic
cycles gives examples of cycles with very high magnetic energy. Our preliminary
estimations, however, suggest that the probability of solar superflares is
extremely low.


title:
Constraining the size of the Comptonizing medium by modeling the energy
  dependent time-lags of kHz QPOs of Neutron star system

abstract:
  In earlier works, we had shown that the observed soft lags and r.m.s versus
energy of the lower kHz QPO of neutron star binaries can be explained in the
framework of a thermal Comptonization model. It was also shown that such an
interpretation can provide estimates of the size and geometry of the
Comptonizing medium. Here we study the dependence of these estimates on the
time-averaged spectral model assumed and on the frequency of the QPO. We use
the high quality time lag and r.m.s obtained during March 3rd 1996 observation
of 4U 1608-52 by RXTE as well as other observations of the source at different
QPO frequencies where a single time-lag between two broad energy bands have
been reported. We compare the results obtained when assuming that the
time-averaged spectra are represented by the spectrally degenerate "hot" and
"cold" seed photon spectral models. We find that for the "hot" seed photon
model the medium size is in the range of 0.3-2.0 kms and the size decreases
with increasing QPO frequency. On the other hand for the "cold" seed photon
model the range for the sizes are much larger 0.5-20 kms and hence perhaps show
no variation with QPO frequency. Our results emphasis the need for broad band
spectral information combined with high frequency timing to lift this
degeneracy. We further show that the r.m.s as a function of energy for the
upper kHz QPO is similar to the lower one and indeed we find that the driver
for this QPO should be temperature variations of the corona identical to the
lower kHz QPO. However, the time lag reported for the upper kHz QPO is hard,
which if confirmed, would challenge the simple Comptonization model presented
here. It would perhaps imply that reverberation lags are also important and/or
the dominate spectral component is not a single temperature medium but a
multi-temperature complex one.


title:
Rapidity bin multiplicity correlations from a multi-phase transport
  model

abstract:
  The central-arbitrary bin and forward-backward bin multiplicity correlation
patterns for Au+Au collisions at $\sqrt{s_{NN}} $= $7.7-62.4$ GeV are
investigated within a multi-phase transport (AMPT) model. An interesting
observation is that for $\sqrt{s_{NN}} <19.6$ GeV Au+Au collisions, these two
correlation patterns both have an increase with the pseudorapidity gap, while
for $\sqrt{s_{NN}} >19.6$ GeV Au+Au collisions, they decrease. We mainly
discuss the influence of different evolution stages of collision system on the
central-arbitrary bin correlations, such as the initial conditions, partonic
scatterings, hadronization scheme and hadronic scatterings. Our results show
that the central-arbitrary bin multiplicity correlations have different
responses to partonic phase and hadronic phase, which can be suggested as a
good probe to explore the dynamical evolution mechanism of the hot dense matter
in high-energy heavy-ion collisions.