title:
A sufficient condition for a Rational Differential Operator to generate
  an Integrable System

abstract:
  For a rational differential operator $L=AB^{-1}$, the Lenard-Magri scheme of
integrability is a sequence of functions $F_n, n\geq 0$, such that (1)
$B(F_{n+1})=A(F_n)$ for all $n \geq 0$ and (2) the functions $B(F_n)$ pairwise
commute. We show that, assuming that property $(1)$ holds and that the set of
differential orders of $B(F_n)$ is unbounded, property $(2)$ holds if and only
if $L$ belongs to a class of rational operators that we call integrable. If we
assume moreover that the rational operator $L$ is weakly non-local and
preserves a certain splitting of the algebra of functions into even and odd
parts, we show that one can always find such a sequence $(F_n)$ starting from
any function in Ker B. This result gives some insight in the mechanism of
recursion operators, which encode the hierarchies of the corresponding
integrable equations.


title: Physical electrostatics of small field emitter arrays/clusters

abstract:
  This paper improves understanding of electrostatic influences on apex field
enhancement factors (AFEFs) for small field emitter arrays. Using the "floating
sphere at emitter-plate potential" (FSEPP) model, it re-examines the
electrostatics and mathematics of three simple systems of identical post-like
emitters. For the isolated emitter, various approaches are noted. On need
consider only the effects of sphere charges and (for separated emitters) image
charges. For the 2-emitter system, formulas are found for "charge-blunting" and
"neighbour-field" effects, for widely spaced and "sufficiently closely spaced"
emitters. Mutual charge-blunting is always dominant, with a related (negative)
fractional AFEF-change {\delta}_two. For sufficiently small emitter spacing c,
|{\delta}_two| varies as 1/c; for large spacing, |{\delta}_two| decreases as
1/c^3. In a 3-emitter linear array, differential charge-blunting and
differential neighbor-field effects occur, but the former are dominant, and
cause the "exposed" outer emitters to have higher AFEF ({\gamma}_0) than the
central emitter ({\gamma}_1). Formulas are found for the exposure ratio
{\Xi}={\gamma}_0/{\gamma}_1, for large and for sufficiently small separations.
The FSEPP model for an isolated emitter has accuracy around 30%. Line-charge
models (LCMs) are an alternative, but an apparent difficulty with recent LCM
models is identified. Better descriptions of array electrostatics may involve
developing good fitting equations for AFEFs derived from accurate numerical
solution of Laplace's equation, perhaps with equation form(s) guided
qualitatively by FSEPP-model results. In existing fitting formulas, the
AFEF-reduction decreases exponentially as c increases, which differs from
FSEPP-model formulas. FSEPP models might provide a useful guide to the
qualitative behaviour of small field emitter clusters larger than those
investigated.


title:
Elliptic Curves with Isomorphic Groups of Points over Finite Field
  Extensions

abstract:
  Consider a pair of ordinary elliptic curves $E$ and $E'$ defined over the
same finite field $\mathbb{F}_q$. Suppose they have the same number of
$\mathbb{F}_q$-rational points, i.e. $|E(\mathbb{F}_q)|=|E'(\mathbb{F}_q)|$. In
this paper we characterise for which finite field extensions
$\mathbb{F}_{q^k}$, $k\geq 1$ (if any) the corresponding groups of
$\mathbb{F}_{q^k}$-rational points are isomorphic, i.e. $E(\mathbb{F}_{q^k})
\cong E'(\mathbb{F}_{q^k})$.


title:
Lipschitz continuity in the Hurst parameter of functionals of stochastic
  differential equations driven by a fractional Brownian motion

abstract:
  Sensitivity analysis w.r.t. the long-range/memory noise parameter for
probability distributions of functionals of solutions to stochastic
differential equations is an important stochastic modeling issue in many
applications.
  In this paper we consider solutions $\{X^H_t\}_{t\in \mathbb{R}_+}$ to
stochastic differential equations driven by fractional Brownian motions. We
develop two innovative sensitivity analyses when the Hurst parameter $H$ of the
noise tends to the critical Brownian parameter $H=\tfrac{1}{2}$ from above or
from below. First, we examine expected smooth functions of $X^H$ at a fixed
time horizon $T$. Second, we examine Laplace transforms of functionals which
are irregular with regard to Malliavin calculus, namely, first passage times of
$X^H$ at a given threshold.
  In both cases we exhibit the Lipschitz continuity w.r.t. $H$ around the value
$\tfrac{1}{2}$. Therefore, our results show that the Markov Brownian model is a
good proxy model as long as the Hurst parameter remains close to
$\tfrac{1}{2}$.


title:
Strong-field Breit-Wheeler pair production in short laser pulses:
  Relevance of spin effects

abstract:
  Production of electron-positron pairs in the collision of a high-energy
photon with a high-intensity few-cycle laser pulse is studied. By utilizing the
frameworks of laser-dressed spinor and scalar quantum electrodynamics, a
comparison between the production of pairs of Dirac and Klein-Gordon particles
is drawn. Positron energy spectra and angular distributions are presented for
various laser parameters. We identify conditions under which predictions from
Klein-Gordon theory either closely resemble or largely differ from those of the
proper Dirac theory. In particular, we address the question to which extent the
relevance of spin effects is influenced by the short duration of the laser
pulse.


title: On-the-fly Network Pruning for Object Detection

abstract:
  Object detection with deep neural networks is often performed by passing a
few thousand candidate bounding boxes through a deep neural network for each
image. These bounding boxes are highly correlated since they originate from the
same image. In this paper we investigate how to exploit feature occurrence at
the image scale to prune the neural network which is subsequently applied to
all bounding boxes. We show that removing units which have near-zero activation
in the image allows us to significantly reduce the number of parameters in the
network. Results on the PASCAL 2007 Object Detection Challenge demonstrate that
up to 40% of units in some fully-connected layers can be entirely eliminated
with little change in the detection result.


title:
Responsibility and Tangible Security: Towards a Theory of User
  Acceptance of Security Tokens

abstract:
  Security and usability issues with passwords suggest a need for a new
authentication scheme. Several alternatives involve a physical device or token.
We investigate one such alternative, Pico: an authentication scheme that
utilizes multiple wearable devices. We present the grounded theory results of a
series of semi-structured interviews for exploring perceptions of this scheme.
We found that the idea of carrying physical devices increases perceived
personal responsibility for secure authentication, making the risks and
inconvenience associated with loss and theft salient for participants. Although
our work is focused on Pico, the results of the study contribute to a broader
understanding of user perception and concerns of responsibility for any
token-based authentication schemes.


title: Competition of simple and complex adoption on interdependent networks

abstract:
  We consider the competition of two mechanisms for adoption processes: a
so-called complex threshold dynamics and a simple
Susceptible-Infected-Susceptible (SIS) model. Separately, these mechanisms
lead, respectively, to first order and continuous transitions between
non-adoption and adoption phases. We consider two interconnected layers. While
all nodes on the first layer follow the complex adoption process, all nodes on
the second layer follow the simple adoption process. Coupling between the two
adoption processes occurs as a result of the inclusion of some additional
interconnections between layers. We find that the transition points and also
the nature of the transitions are modified in the coupled dynamics. In the
complex adoption layer, the critical threshold required for extension of
adoption increases with interlayer connectivity whereas in the case of an
isolated single network it would decrease with average connectivity. In
addition, the transition can become continuous depending on the detailed inter
and intralayer connectivities. In the SIS layer, any interlayer connectivity
leads to the extension of the adopter phase. Besides, a new transition appears
as as sudden drop of the fraction of adopters in the SIS layer. The main
numerical findings are described by a mean-field type analytical approach
appropriately developed for the threshold-SIS coupled system.


title:
Upper Bounds on the Quantifier Depth for Graph Differentiation in
  First-Order Logic

abstract:
  We show that on graphs with n vertices, the 2-dimensional Weisfeiler-Leman
algorithm requires at most O(n^2/log(n)) iterations to reach stabilization.
This in particular shows that the previously best, trivial upper bound of
O(n^2) is asymptotically not tight. In the logic setting, this translates to
the statement that if two graphs of size n can be distinguished by a formula in
first-order logic with counting with 3 variables (i.e., in C3), then they can
also be distinguished by a C3-formula that has quantifier depth at most
O(n^2/log(n)).
  To prove the result we define a game between two players that enables us to
decouple the causal dependencies between the processes happening simultaneously
over several iterations of the algorithm. This allows us to treat large color
classes and small color classes separately. As part of our proof we show that
for graphs with bounded color class size, the number of iterations until
stabilization is at most linear in the number of vertices. This also yields a
corresponding statement in first-order logic with counting.
  Similar results can be obtained for the respective logic without counting
quantifiers, i.e., for the logic L3.


title: Tweet2Vec: Character-Based Distributed Representations for Social Media

abstract:
  Text from social media provides a set of challenges that can cause
traditional NLP approaches to fail. Informal language, spelling errors,
abbreviations, and special characters are all commonplace in these posts,
leading to a prohibitively large vocabulary size for word-level approaches. We
propose a character composition model, tweet2vec, which finds vector-space
representations of whole tweets by learning complex, non-local dependencies in
character sequences. The proposed model outperforms a word-level baseline at
predicting user-annotated hashtags associated with the posts, doing
significantly better when the input contains many out-of-vocabulary words or
unusual character sequences. Our tweet2vec encoder is publicly available.


title:
What's in a pattern? Examining the Type of Signal Multivariate Analysis
  Uncovers At the Group Level

abstract:
  Multivoxel pattern analysis (MVPA) has gained enormous popularity in the
neuroimaging community over the past few years. At the group level, most MVPA
studies adopt an "information based" approach in which the sign of the effect
of individual subjects is discarded and a non-directional summary statistic is
carried over to the second level. This is in contrast to a directional
"activation based" approach typical in univariate group level analysis, in
which both signal magnitude and sign are taken into account. The transition
from examining effects in one voxel at a time vs. several voxels (univariate
vs. multivariate) has thus tacitly entailed a transition from directional to
non-directional signal definition at the group level. While a directional
group-level MVPA approach implies that individuals have similar multivariate
spatial patterns of activity, in a non-directional approach each individual may
have a distinct spatial pattern. Using an experimental dataset, we show that
directional and non-directional group-level MVPA approaches uncover distinct
brain regions with only partial overlap. We propose a method to quantify the
degree of spatial similarity in activation patterns over subjects. Applied to
an auditory task, we find higher values in auditory regions compared to control
regions.


title: Real-time 3D Tracking of Articulated Tools for Robotic Surgery

abstract:
  In robotic surgery, tool tracking is important for providing safe tool-tissue
interaction and facilitating surgical skills assessment. Despite recent
advances in tool tracking, existing approaches are faced with major
difficulties in real-time tracking of articulated tools. Most algorithms are
tailored for offline processing with pre-recorded videos. In this paper, we
propose a real-time 3D tracking method for articulated tools in robotic
surgery. The proposed method is based on the CAD model of the tools as well as
robot kinematics to generate online part-based templates for efficient 2D
matching and 3D pose estimation. A robust verification approach is incorporated
to reject outliers in 2D detections, which is then followed by fusing inliers
with robot kinematic readings for 3D pose estimation of the tool. The proposed
method has been validated with phantom data, as well as ex vivo and in vivo
experiments. The results derived clearly demonstrate the performance advantage
of the proposed method when compared to the state-of-the-art.


title:
Van der Waals torque and force between dielectrically anisotropic
  layered media

abstract:
  We analyse van der Waals interactions between a pair of dielectrically
anisotropic plane-layered media interacting across a dielectrically isotropic
solvent medium. We develop a general formalism based on transfer matrices to
investigate the van der Waals torque and force in the limit of weak
birefringence and dielectric matching between the ordinary axes of the
anisotropic layers and the solvent. We apply this formalism to study the
following systems: (i) a pair of single anisotropic layers, (ii) a single
anisotropic layer interacting with a multilayered slab consisting of
alternating anisotropic and isotropic layers, and (iii) a pair of multilayered
slabs each consisting of alternating anisotropic and isotropic layers, looking
at the cases where the optic axes lie parallel and/or perpendicular to the
plane of the layers. For the first case, the optic axes of the oppositely
facing anisotropic layers of the two interacting slabs generally possess an
angular mismatch, and within each multilayered slab the optic axes may either
be the same, or undergo constant angular increments across the anisotropic
layers. In particular, we examine how the behaviors of the van der Waals torque
and force can be "tuned" by adjusting the layer thicknesses, the relative
angular increment within each slab, and the angular mismatch between the slabs.

categories: cond-mat.soft cond-mat.mes-hall cond-mat.mtrl-sci physics.chem-ph physics.optics


title:
Investigating the opportunities of using mobile learning by young
  children in Bulgaria

abstract:
  This paper provides an analysis of literature related to the use of mobile
devices in teaching young children. For this purpose, the most popular mobile
operating systems in Bulgaria are considered and the functionality of the
existing mobile applications with Bulgarian interface is discussed. The results
of a survey of parents' views regarding the mobile devices as a learning tool
are presented and the ensuing conclusions are provided.


title: An Overview of Spatial Econometrics

abstract:
  This paper offers an expository overview of the field of spatial
econometrics. It first justifies the necessity of special statistical
procedures for the analysis of spatial data and then proceeds to describe the
fundamentals of these procedures. In particular, this paper covers three
crucial techniques for building models with spatial data. First, we discuss how
to create a spatial weights matrix based on the distances between each data
point in a dataset. Next, we describe the conventional methods to formally
detect spatial autocorrelation, both global and local. Finally, we outline the
chief components of a spatial autoregressive model, noting the circumstances
under which it would be appropriate to incorporate each component into a model.
This paper seeks to offer a concise introduction to spatial econometrics that
will be accessible to interested individuals with a background in statistics or
econometrics.


title: Martian north polar cap summer water cycle

abstract:
  A key outstanding question in Martian science is 'are the polar caps gaining
or losing mass and what are the implications for past, current and future
climate?' To address this question, we use observations from the Compact
Reconnaissance Imaging Spectrometer for Mars (CRISM) of the north polar cap
during late summer for multiple Martian years, to monitor the summertime water
cycle in order to place quantitative limits on the amount of water ice
deposited and sublimed in late summer.
  We establish here for the first time the summer cycle of water ice absorption
band signatures on the north polar cap. We show that in a key region in the
interior of the north polar cap, the absorption band depths grow until Ls=120,
when they begin to shrink, until they are obscured at the end of summer by the
north polar hood. This behavior is transferable over the entire north polar
cap, where in late summer regions 'flip' from being net sublimating into net
condensation mode. This transition or 'mode flip' happens earlier for regions
closer to the pole, and later for regions close to the periphery of the cap.
  The observations and calculations presented herein estimate that on average a
water ice layer ~70 microns thick is deposited during the Ls=135-164 period.
This is far larger than the results of deposition on the south pole during
summer, where an average layer 0.6-6 microns deep has been estimated by Brown
et al. (2014).


title: Proton structure in high-energy high-multiplicity p-p collisions

abstract:
  A few-body proton image, expected to be derivable from QCD in the
renormalization group procedure for effective particles, is used within the
Monte Carlo Glauber model to calculate the anisotropy coefficients in the
initial collision-state of matter in high-energy high-multiplicity
proton-proton interaction events. We estimate the ridge-like correlations in
the final hadronic state by assuming their proportionality to the initial
collision-state anisotropy. In our estimates, some distinct few-body proton
structures appear capable of accounting for the magnitude of p-p ridge effect,
with potentially discernible differences in dependence on multiplicity.


title:
Real-time shot-noise-limited differential photodetection for atomic
  quantum control

abstract:
  We demonstrate high-efficiency, shot-noise-limited differential
photodetection with real-time signal conditioning, suitable for feedback-based
quantum control of atomic systems. The detector system has quantum efficiency
of 0.92, is shot-noise limited from 7.4 x 10^5 to 3.7 x 10^8 photons per pulse,
and provides real-time voltage-encoded output at up to 2.3 Mpulses per second.


title: Aperture effects on the oxygen abundance determinations from CALIFA data

abstract:
  This paper aims at providing aperture corrections for emission lines in a
sample of spiral galaxies from the Calar Alto Legacy Integral Field Area Survey
(CALIFA) database. In particular, we explore the behavior of the
log([OIII]5007/Hbeta)/([NII]6583/Halpha) (O3N2) and log[NII]6583/Halpha (N2)
flux ratios since they are closely connected to different empirical
calibrations of the oxygen abundances in star forming galaxies.
  We compute median growth curves of Halpha, Halpha/Hbeta, O3N2 and N2 up to
2.5R_50 and 1.5 disk R_eff. The growth curves simulate the effect of observing
galaxies through apertures of varying radii. The median growth curve of the
Halpha/Hbeta ratio monotonically decreases from the center towards larger
radii, showing for small apertures a maximum value of ~10% larger than the
integrated one. The median growth curve of N2 shows a similar behavior,
decreasing from the center towards larger radii. No strong dependence is seen
with the inclination, morphological type and stellar mass for these growth
curves. Finally, the median growth curve of O3N2 increases monotonically with
radius. However, at small radii it shows systematically higher values for
galaxies of earlier morphological types and for high stellar mass galaxies.
  Applying our aperture corrections to a sample of galaxies from the SDSS
survey at 0.02<=z<=0.3 shows that the average difference between fiber-based
and aperture corrected oxygen abundances, for different galaxy stellar mass and
redshift ranges, reaches typically to ~11%, depending on the abundance
calibration used. This average difference is found to be systematically biased,
though still within the typical uncertainties of oxygen abundances derived from
empirical calibrations. Caution must be exercised when using observations of
galaxies for small radii (e.g. below 0.5R_eff) given the high dispersion shown
around the median growth curves.


title: The Defect of Random Hyperspherical Harmonics

abstract:
  Random hyperspherical harmonics are Gaussian Laplace eigenfunctions on the
unit $d$-sphere ($d\ge 2$). We investigate the distribution of their defect
i.e., the difference between the measure of positive and negative regions.
Marinucci and Wigman studied the two-dimensional case giving the asymptotic
variance (Marinucci and Wigman 2011) and a Central Limit Theorem (Marinucci and
Wigman 2014), both in the high-energy limit. Our main results concern
asymptotics for the defect variance and quantitative CLTs in Wasserstein
distance, in any dimension. The proofs are based on Wiener-It\^o chaos
expansions for the defect, a careful use of asymptotic results for all order
moments of Gegenbauer polynomials and Stein-Malliavin approximation techniques
by Nourdin and Peccati. Our argument requires some novel technical results of
independent interest that involve integrals of the product of three
hyperspherical harmonics.


title:
On A Covariant Hamiltonian Description of Palatini's Gravity on
  Manifolds with Boundary

abstract:
  A covariant Hamiltonian description of Palatini's gravity on manifolds with
boundary is presented. Palatini's gravity appears as a gauge theory satisfying
a constraint in a certain topological limit. This approach allows the
consideration of non-trivial topological situations. The multisymplectic
framework for first-order covariant Hamiltonian field theories on manifolds
with boundary, developed in [Ib15], enables analysis of the system at the
boundary. The reduced phase space of the system is determined to be a
symplectic manifold with a distinguished isotropic submanifold corresponding to
the boundary data of the solutions of the Euler-Lagrange equations.


title: Cocenters and representations of pro-$p$ Hecke algebras

abstract:
  In this paper, we study the relation between the cocenter and the
representations of an affine pro-$p$ Hecke algebra. As a consequence, we obtain
a new criterion on the supersingular representation: a (virtual) representation
is supersingular if and only if its character vanishes on the non-supersingular
part of the cocenter.


title: Relativistic Doppler beaming and misalignments in AGN jets

abstract:
  Radio maps of AGNs often show linear features, called jets, both on pc as
well as kpc scales. These jets supposedly possess relativistic motion and are
oriented close to the line of sight of the observer and accordingly the
relativistic Doppler beaming makes them look much brighter than they really are
in their respective rest-frames. The flux boosting due to the relativistic
beaming is a very sensitive factor of the jet orientation angle, as seen by the
observer. Quite often large bends are seen in these jets, with misalignments
being $90^\circ$ or more and might imply a change in the orientation angle that
could cause a large change in the relativistic beaming factor. Such large bends
should show high contrasts in the brightness of the jets, before and after the
misalignments, if relativistic beaming does play an important role in these
jets. It needs to be kept in mind that sometimes a small intrinsic change in
the jet angle might appear as a much larger misalignment due to the geometrical
projection effects, especially when seen close to the line of sight. Of course
what really matters is the final orientation angle of the jet with respect to
the observer's line of sight. Taking the geometrical projection effects
properly into account, we calculate the consequences of the presumed
relativistic beaming and demonstrate that there ought to be large brightness
ratios in jets before and after the observed misalignments.


title:
Measurement of the inclusive isolated prompt photon cross section in
  $pp$ collisions at $\sqrt{s} = 8$ TeV with the ATLAS detector

abstract:
  A measurement of the cross section for the inclusive production of isolated
prompt photons in proton-proton collisions at a centre-of-mass energy of
$\sqrt{s} = 8$ TeV is presented. The measurement covers the pseudo rapidity
ranges $|\eta^{\gamma}| < 1.37$ and $1.56 \leq |\eta^{\gamma}| < 2.37$ in the
transverse energy range $25 < E_{\rm T}^{\gamma} < 1500$ GeV. The results are
based on an integrated luminosity of 20.2 fb$^{-1}$, recorded by the ATLAS
detector at the LHC. Photon candidates are identified by combining information
from the calorimeters and the inner tracker. The background is subtracted using
a data-driven technique, based on the observed calorimeter shower-shape
variables and the deposition of hadronic energy in a narrow cone around the
photon candidate. The measured cross sections are compared with leading-order
and next-to-leading order perturbative QCD calculations and are found to be in
a good agreement over ten orders of magnitude.


title: Compressed Sensing for Time-Frequency Gravitational Wave Data Analysis

abstract:
  The potential of compressed sensing for obtaining sparse time-frequency
representations for gravitational wave data analysis is illustrated by
comparison with existing methods, as regards i) shedding light on the fine
structure of noise transients (glitches) in preparation of their
classification, and ii) boosting the performance of waveform consistency tests
in the detection of unmodeled transient gravitational wave signals using a
network of detectors affected by unmodeled noise transient


title:
Exploring metamagnetism of single crystalline \eun\ by neutron
  scattering

abstract:
  We present here a neutron diffraction study, both in zero field and as a
function of magnetic field, of the magnetic structure of the tetragonal
intermetallic \eun\ on a single crystalline sample. This material is known to
undergo a cascade of transitions, first at 13.2\,K towards an incommensurate
modulated magnetic structure, then at 10.5\,K to an equal moment, yet
undetermined, antiferromagnetic structure. We show here that the low
temperature phase presents a spiral moment arrangement with wave-vector {\bf k}
= ($\frac{1}{4},\delta,0)$. For a magnetic field applied along the tetragonal
{\bf c}-axis, the square root of the scattering intensity of a chosen
reflection matches very well the complex metamagnetic behavior of the
magnetization along {\bf c} measured previously. For the magnetic field applied
along the {\bf b}-axis, two magnetic transitions are observed below the
transition to a fully polarized state.


title: Deep Neural Networks Under Stress

abstract:
  In recent years, deep architectures have been used for transfer learning with
state-of-the-art performance in many datasets. The properties of their features
remain, however, largely unstudied under the transfer perspective. In this
work, we present an extensive analysis of the resiliency of feature vectors
extracted from deep models, with special focus on the trade-off between
performance and compression rate. By introducing perturbations to image
descriptions extracted from a deep convolutional neural network, we change
their precision and number of dimensions, measuring how it affects the final
score. We show that deep features are more robust to these disturbances when
compared to classical approaches, achieving a compression rate of 98.4%, while
losing only 0.88% of their original score for Pascal VOC 2007.


title: Model simplification and loss of irreversibility

abstract:
  In this paper, we reveal a general relationship between model simplification
and irreversibility based on the model of continuous-time Markov chains with
time-scale separation. According to the topological structure of the fast
process, we divide the states of the chain into the transient states and the
recurrent states. We show that a two-time-scale chain can be simplified to a
reduced chain in two different ways: removal of the transient states and
aggregation of the recurrent states. Both the two operations will lead to a
decrease in the entropy production rate and its adiabatic part and will keep
its non-adiabatic part the same. This suggests that although model
simplification can retain almost all the dynamic information of the chain, it
will lose some thermodynamic information as a trade-off.

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


title: HMI Synoptic Maps Produced by NSO/NISP

abstract:
  Recently, the National Solar Observatory (NSO) Solar-atmosphere Pipeline
Working Group has undertaken the production of synoptic maps from Helioseismic
and Magnetic Imager (HMI) magnetograms. A set of maps has been processed
spanning the data available for 2010-2015 using twice daily images (taken at UT
midnight and noon) and running them through the same algorithms used to produce
SOLIS/VSM 6302l mean-magnetic and spatial-variance maps. The contents of this
document provide an overview of what these maps look like, and the processing
steps used to generate them from the original HMI input data.


title: Is Leibnizian calculus embeddable in first order logic?

abstract:
  To explore the extent of embeddability of Leibnizian infinitesimal calculus
in first-order logic (FOL) and modern frameworks, we propose to set aside
ontological issues and focus on procedural questions. This would enable an
account of Leibnizian procedures in a framework limited to FOL with a small
number of additional ingredients such as the relation of infinite proximity.
If, as we argue here, first order logic is indeed suitable for developing
modern proxies for the inferential moves found in Leibnizian infinitesimal
calculus, then modern infinitesimal frameworks are more appropriate to
interpreting Leibnizian infinitesimal calculus than modern Weierstrassian ones.
  Keywords: First order logic; infinitesimal calculus; ontology; procedures;
Leibniz; Weierstrass; Abraham Robinson


title: A solution to the reversible embedding problem for finite Markov chains

abstract:
  The embedding problem for Markov chains is a famous problem in probability
theory and only partial results are available up till now. In this paper, we
propose a variant of the embedding problem called the reversible embedding
problem which has a deep physical and biochemical background and provide a
complete solution to this new problem. We prove that the reversible embedding
of a stochastic matrix, if it exists, must be unique. Moreover, we obtain the
sufficient and necessary conditions for the existence of the reversible
embedding and provide an effective method to compute the reversible embedding.
Some examples are also given to illustrate the main results of this paper.


title:
Efficient algorithms for the inversion of the cumulative central beta
  distribution

abstract:
  Accurate and efficient algorithms for the inversion of the cumulative central
beta distribution are described. The algorithms are based on the combination of
a fourth-order fixed point method with good non-local convergence properties
(the Schwarzian-Newton method), asymptotic inversion methods and sharp bounds
in the tails of the distribution function.


title: Testing gravity theories using tensor perturbations

abstract:
  Primordial gravitational waves constitute a promising probe of the very early
Universe and the laws of gravity. We study in this work changes to tensor-mode
perturbations (TMPs) that can arise in various proposed modified gravity (MG)
theories. These include additional friction effects, nonstandard dispersion
relations involving a massive graviton, a modified speed, and a small-scale
modification. We introduce a physically motivated parameterization of these
effects and use current available data to obtain exclusion regions in the
parameter spaces. Taking into account the foreground subtraction, we then
perform a forecast analysis focusing on tensor-mode MG parameters as
constrained by future experiments COrE, Stage-IV and PIXIE. For a fiducial
value of the tensor-to-scalar ratio $r=0.01$, we find that an additional
friction of $3.5\sim4.5\%$ compared to GR will be detected at $3$-$\sigma$ by
these experiments, while a decrease in friction will be more difficult to
detect. The speed of gravitational waves needs to be by $5\sim15\%$ different
from the speed of light for detection. We find that the minimum detectable
graviton mass is about $7.8\sim9.7\times 10^{-33}$ eV, which is of the same
order of magnitude as the graviton mass that allows massive gravity theories to
produce cosmic acceleration. Finally, we study TMPs in MG during inflation
using our parameterization. We find that the tensor spectral index is related
to $r$ and the friction parameter $\nu_0$ by $n_T=-3\nu_0-r/8$. Assuming that
the friction parameter is unchanged throughout the history of the Universe and
is much larger than $r$, future experiments will be able to distinguish this MG
consistency relation from the standard inflation one, and thus can be used as a
further test of MG. In summary, TMPs and cosmic-microwave-background B-mode
polarization provide a complementary avenue to test gravity theories.
(Abridged)


title: Oscillator metrology with software defined radio

abstract:
  Analog electrical elements such as mixers, filters, transfer oscillators,
isolating buffers, dividers, and even transmission lines contribute technical
noise and unwanted environmental coupling in time and frequency measurements.
Software defined radio (SDR) techniques replace many of these analog components
with digital signal processing (DSP) on rapidly sampled signals. We demonstrate
that, generically, commercially available multi-channel SDRs are capable of
time and frequency metrology, outperforming purpose-built devices by as much as
an order-of-magnitude. For example, for signals at 10 MHz and 6 GHz, we observe
SDR time deviation noise floors of about 20 fs and 1 fs, respectively, in under
10 ms of averaging. Examining the other complex signal component, we find a
relative amplitude measurement instability of 3e-7 at 5 MHz. We discuss the
scalability of a SDR-based system for simultaneous measurement of many clocks.
SDR's frequency agility allows for comparison of oscillators at widely
different frequencies. We demonstrate a novel and extreme example with optical
clock frequencies differing by many terahertz: using a femtosecond-laser
frequency comb and SDR, we show femtosecond-level time comparisons of
ultra-stable lasers with zero measurement dead-time.


title:
Characterizing Quantifier Fuzzification Mechanisms: a behavioral guide
  for practical applications

abstract:
  Important advances have been made in the fuzzy quantification field.
Nevertheless, some problems remain when we face the decision of selecting the
most convenient model for a specific application. In the literature, several
desirable adequacy properties have been proposed, but theoretical limits impede
quantification models from simultaneously fulfilling every adequacy property
that has been defined. Besides, the complexity of model definitions and
adequacy properties makes very difficult for real users to understand the
particularities of the different models that have been presented. In this work
we will present several criteria conceived to help in the process of selecting
the most adequate Quantifier Fuzzification Mechanisms for specific practical
applications. In addition, some of the best known well-behaved models will be
compared against this list of criteria. Based on this analysis, some guidance
to choose fuzzy quantification models for practical applications will be
provided.


title:
Planck intermediate results. XLVII. Planck constraints on reionization
  history

abstract:
  We investigate constraints on cosmic reionization extracted from the Planck
cosmic microwave background (CMB) data. We combine the Planck CMB anisotropy
data in temperature with the low-multipole polarization data to fit LCDM models
with various parameterizations of the reionization history. We obtain a Thomson
optical depth tau=0.058 +/- 0.012 for the commonly adopted instantaneous
reionization model. This confirms, with only data from CMB anisotropies, the
low value suggested by combining Planck 2015 results with other data sets and
also reduces the uncertainties. We reconstruct the history of the ionization
fraction using either a symmetric or an asymmetric model for the transition
between the neutral and ionized phases. To determine better constraints on the
duration of the reionization process, we also make use of measurements of the
amplitude of the kinetic Sunyaev-Zeldovich (kSZ) effect using additional
information from the high resolution Atacama Cosmology Telescope and South Pole
Telescope experiments. The average redshift at which reionization occurs is
found to lie between z=7.8 and 8.8, depending on the model of reionization
adopted. Using kSZ constraints and a redshift-symmetric reionization model, we
find an upper limit to the width of the reionization period of Dz < 2.8. In all
cases, we find that the Universe is ionized at less than the 10% level at
redshifts above z~10. This suggests that an early onset of reionization is
strongly disfavoured by the Planck data. We show that this result also reduces
the tension between CMB-based analyses and constraints from other astrophysical
sources.


title: A Poisson process reparameterisation for Bayesian inference for extremes

abstract:
  A common approach to modelling extreme values is to consider the excesses
above a high threshold as realisations of a non-homogeneous Poisson process.
While this method offers the advantage of modelling using threshold-invariant
extreme value parameters, the dependence between these parameters makes
estimation more difficult. We present a novel approach for Bayesian estimation
of the Poisson process model parameters by reparameterising in terms of a
tuning parameter $m$. This paper presents a method for choosing the optimal
value of m that near-orthogonalises the parameters, which is achieved by
minimising the correlation between the asymptotic posterior distribution of the
parameters. This choice of m ensures more rapid convergence and efficient
sampling from the joint posterior distribution using Markov Chain Monte Carlo
methods. Samples from the parameterisation of interest are then obtained by a
simple transform. Results are presented in the cases of identically and
non-identically distributed models for extreme rainfall in Cumbria, UK.


title: A new flocking model through body attitude coordination

abstract:
  We present a new model for multi-agent dynamics where each agent is described
by its position and body attitude: agents travel at a constant speed in a given
direction and their body can rotate around it adopting different
configurations. In this manner, the body attitude is described by three
orthonormal axes giving an element in $SO(3)$ (rotation matrix). Agents try to
coordinate their body attitudes with the ones of their neighbours. In the
present paper, we give the Individual Based Model (particle model) for this
dynamics and derive its corresponding kinetic and macroscopic equations.


title:
Global Existence of Finite Energy Weak Solutions of Quantum
  Navier-Stokes Equations

abstract:
  In this paper we consider the Quantum Navier-Stokes system both in two and in
three space dimensions and prove global existence of finite energy weak
solutions for large initial data. In particular, the notion of weak solutions
is the standard one. This means that the vacuum region are included in the weak
formulations. In particular, no extra term like damping or cold pressure are
added to the system in order to define the velocity field in the vacuum region.
The main contribution of this paper is the construction of a regular
approximating system consistent with the effective velocity transformation
needed to get necessary a priori estimates.


title: Experimental studies of crystal nucleation: metals and colloids

abstract:
  Crystallization is one of the most important phase transformations of first
order. In the case of metals and alloys, the liquid phase is the parent phase
of materials production. The conditions of the crystallization process control
the as-solidified material in its chemical and physical properties. Nucleation
initiates the crystallization of a liquid. It selects the crystallographic
phase, stable or meta-stable. Its detailed knowledge is therefore mandatory for
the design of materials. We present techniques of containerless processing for
nucleation studies of metals and alloys. We demonstrate the power of these
methods for crystal nucleation of stable solids but in particular also for
investigations of crystal nucleation of metastable solids at extreme
undercooling. This concerns the issue of heterogeneous versus homogeneous
nucleation and non-equilibrium conditions. The results are analyzed within
classical nucleation theory, where the activation energy of homogeneous
nucleation depends on the interfacial energy and the difference of Gibbs free
energies of solid and liquid. The interfacial energy acts as barrier for the
nucleation process. Its experimental determination is difficult in the case of
metals. In the second part of this work we therefore explore the use of
colloidal suspensions as models for the crystallization process. Their
nucleation process is observed in situ by optical techniques and ultra-small
angle X-ray diffraction using high intensity synchrotron radiation. It allows
an unambiguous discrimination of homogeneous and heterogeneous nucleation as
well as the determination of the interfacial free energy of the solid-liquid
interface. Our results are used to construct Turnbull plots of colloids, which
are discussed in relation to Turnbull plots of metals and support the
hypothesis that colloids are useful model systems to investigate crystal
nucleation.


title:
Doob-Martin compactification of a Markov chain for growing random words
  sequentially

abstract:
  We consider a Markov chain that iteratively generates a sequence of random
finite words in such a way that the $n^{\mathrm{th}}$ word is uniformly
distributed over the set of words of length $2n$ in which $n$ letters are $a$
and $n$ letters are $b$: at each step an $a$ and a $b$ are shuffled in
uniformly at random among the letters of the current word. We obtain a concrete
characterization of the Doob-Martin boundary of this Markov chain. Writing
$N(u)$ for the number of letters $a$ (equivalently, $b$) in the finite word
$u$, we show that a sequence $(u_n)_{n \in \mathbb{N}}$ of finite words
converges to a point in the boundary if, for an arbitrary word $v$, there is
convergence as $n$ tends to infinity of the probability that the selection of
$N(v)$ letters $a$ and $N(v)$ letters $b$ uniformly at random from $u_n$ and
maintaining their relative order results in $v$. We exhibit a bijective
correspondence between the points in the boundary and ergodic random total
orders on the set $\{a_1, b_1, a_2, b_2, \ldots \}$ that have distributions
which are separately invariant under finite permutations of the indices of the
$a'$s and those of the $b'$s. We establish a further bijective correspondence
between the set of such random total orders and the set of pairs $(\mu,\nu)$ of
diffuse probability measures on $[0,1]$ such that $\frac{1}{2}(\mu+\nu)$ is
Lebesgue measure: the restriction of the random total order to $\{a_1, b_1,
\ldots, a_n, b_n\}$ is obtained by taking $X_1, \ldots, X_n$ (resp. $Y_1,
\ldots, Y_n$) i.i.d. with common distribution $\mu$ (resp. $\nu$), letting
$(Z_1, \ldots, Z_{2n})$ be $\{X_1, Y_1, \ldots, X_n, Y_n\}$ in increasing
order, and declaring that the $k^{\mathrm{th}}$ smallest element in the
restricted total order is $a_i$ (resp. $b_j$) if $Z_k = X_i$ (resp. $Z_k =
Y_j$).


title:
Measurement of the forward-backward asymmetries in the production of
  $\Xi$ and $\Omega$ baryons in $p \bar{p}$ collisions

abstract:
  We measure the forward-backward asymmetries $A_{\rm FB}$ of charged $\Xi$ and
$\Omega$ baryons produced in $p \bar{p}$ collisions recorded by the D0 detector
at the Fermilab Tevatron collider at $\sqrt{s} = 1.96$ TeV as a function of the
baryon rapidity $y$. We find that the asymmetries $A_{\rm FB}$ for charged
$\Xi$ and $\Omega$ baryons are consistent with zero within statistical
uncertainties.


title: Applications of fast triangulation simplification

abstract:
  We describe a new algorithm to compute the geometric intersection number
between two curves, given as edge vectors on an ideal triangulation. Most
importantly, this algorithm runs in polynomial time in the bit-size of the two
edge vectors.
  In its simplest instances, this algorithm works by finding the minimal
position of the two curves. We achieve this by phrasing the problem as a
collection of linear programming problems. We describe how to reduce the more
general case down to one of these simplest instances in polynomial time. This
reduction relies on an algorithm by the first author to quickly switch to a new
triangulation in which an edge vector is significantly smaller.


title:
Avoided ferromagnetic quantum critical point: Antiferromagnetic ground
  state in substituted CeFePO

abstract:
  We have investigated single crystals of two substitution series
Ce(Ru$_{1-x}$Fe$_{x}$)PO and CeFe(As$_{1-y}$P$_{y}$)O in the vicinity to the
quantum critical material CeFePO by means of magnetic-susceptibility and
specific-heat measurements. We observe an antiferromagnetic ground state in the
vicinity of the quantum critical point, with pronounced metamagnetic
transitions for $H\parallel c$, which is the magnetically hard direction. Our
results verify that a ferromagnetic quantum critical point is avoided in
substituted CeFePO, because we clearly demonstrate that the ferromagnetic
ground state changes into an antiferromagnetic one, when approaching the
quantum critical point.


title: Some inequalities for the matrix Heron mean

abstract:
  Let $A, B$ be positive definite matrices, $p=1, 2$ and $r\ge 0$. It is shown
that \begin{equation*} ||A+ B + r(A\sharp_t B+A\sharp_{1-t} B)||_p \le ||A+ B +
r(A^{t}B^{1-t} + A^{1-t}B^t)||_p. \end{equation*} We also prove that for
positive definite matrices $A$ and $B$ \begin{equation*}\label{det} \Dt
(P_{t}(A, B)) \le \Dt (Q_{t}(A, B)), \end{equation*} where $Q_t(A, B)=
\big(\frac{A^t+B^t}{2}\big)^{1/t}$ and $P_t(A, B)$ is the $t$-power mean of $A$
and $B$. As a consequence, we obtain the determinant inequality for the matrix
Heron mean: for any positive definite matrices $A$ and $B,$ $$ \Dt(A+ B +
2(A\sharp B)) \le \Dt(A+ B + A^{1/2}B^{1/2} + A^{1/2}B^{1/2})). $$ These
results complement those obtained by Bhatia, Lim and Yamazaki (LAA, {\bf 501}
(2016) 112-122).


title: Super Bloch Oscillation in a PT symmetric system

abstract:
  Wannier-Stark ladder in a PT symmetric system is generally complex that leads
to amplified/damped Bloch oscillation. We show that a non-amplified wave packet
oscillation with very large amplitude can be realized in a non-Hermitian tight
binding lattice if certain conditions are satisfied. We show that pseudo PT
symmetry guarantees the reality of the quasi energy spectrum in our system.


title: Relaying Strategies for Wireless-Powered MIMO Relay Networks

abstract:
  This paper investigates relaying schemes in an amplify-and-forward
multiple-input multiple-output relay network, where an energy-constrained relay
harvests wireless power from the source information flow and can be further
aided by an energy flow (EF) in the form of a wireless power transfer at the
destination. However, the joint optimization of the relay matrix and the source
precoder for the energy-flow-assisted (EFA) and the non-EFA (NEFA) schemes is
intractable. The original rate maximization problem is transformed into an
equivalent weighted mean square error minimization problem and optimized
iteratively, where the global optimum of the nonconvex source precoder
subproblem is achieved by semidefinite relaxation and rank reduction. The
iterative algorithm finally converges. Then, the simplified EFA and NEFA
schemes are proposed based on channel diagonalization, such that the matrices
optimizations can be simplified to power optimizations. Closed-form solutions
can be achieved. Simulation results reveal that the EFA schemes can outperform
the NEFA schemes. Additionally, deploying more antennas at the relay increases
the dimension of the signal space at the relay. Exploiting the additional
dimension, the EF leakage in the information detecting block can be nearly
separated from the information signal, such that the EF leakage can be
amplified with a small coefficient.


title:
Deriving a complete set of eigendistributions for a gravitational wave
  equation describing the quantized interaction of gravity with a Yang-Mills
  field in case the Cauchy hypersurface is non-compact

abstract:
  In a recent paper we quantized the interaction of gravity with a Yang-Mills
and Higgs field and obtained as a result a gravitational wave equation in a
globally hyperbolic spacetime. Assuming that the Cauchy hypersurfaces are
compact we proved a spectral resolution for the wave equation by applying the
method of separation of variables. In this paper we extend the results to the
case when the Cauchy hypersurfaces are non-compact by considering a Gelfand
triplet and applying the nuclear spectral theorem.


title: An Egorov Theorem for avoided crossings of eigenvalue surfaces

abstract:
  We study nuclear propagation through avoided crossings of electron energy
levels. We construct a surface hopping semigroup, which gives an Egorov-type
description of the dynamics. The underlying time-dependent Schroedinger
equation has a two-by-two matrix-valued potential, whose eigenvalue surfaces
have an avoided crossing. Using microlocal normal forms reminiscent of the
Landau-Zener problem, we prove convergence to the true solution in the
semi-classical limit.


title: Sasakian quiver gauge theory on the Aloff-Wallach space $X_{1,1}$

abstract:
  We consider the SU(3)-equivariant dimensional reduction of gauge theories on
spaces of the form $M^d \times X_{1,1}$ with d-dimensional Riemannian manifold
$M^d$ and the Aloff-Wallach space $X_{1,1}$= SU(3)/U(1) endowed with its
Sasaki-Einstein structure. The condition of SU(3)-equivariance of vector
bundles, which has already occurred in the studies of Spin(7)-instantons on
cones over Aloff-Wallach spaces, is interpreted in terms of quiver diagrams,
and we construct the corresponding quiver bundles, using (parts of) the weight
diagram of SU(3). We consider three examples thereof explicitly and then
compare the results with the quiver gauge theory on $Q_3$ =SU(3)/(U(1) x U(1)),
the leaf space underlying the Sasaki-Einstein manifold $X_{1,1}$. Moreover, we
study instanton solutions on the metric cone $C(X_{1,1})$ by evaluating the
Hermitian Yang-Mills equation. We briefly discuss some features of the moduli
space thereof, following the main ideas of a treatment of Hermitian Yang-Mills
instantons on cones over generic Sasaki-Einstein manifolds in the literature.


title: $p$-local stable cohomological rigidity of quasitoric manifolds

abstract:
  It is proved that if two quasitoric manifolds of dimension $\le 2p^2-4$ for a
prime $p$ have isomorphic cohomology rings, then they have the same $p$-local
stable homotopy type.


title: Quantum Link Homology via Trace Functor I

abstract:
  Motivated by topology, we develop a general theory of traces and shadows for
an endobicategory, which is a~pair: bicategory $\mathbf{C}$ and endobifunctor
$\Sigma\colon \mathbf C \to\mathbf C$. For a graded linear bicategory and a
fixed invertible parameter $q$, we quantize this theory by using the
endofunctor $\Sigma_q$ such that $\Sigma_q \alpha:=q^{-\deg
\alpha}\Sigma\alpha$ for any 2-morphism $\alpha$ and coincides with $\Sigma$
otherwise.
  Applying the quantized trace to the~bicategory of Chen-Khovanov bimodules we
get a new triply graded link homology theory called quantum annular link
homology. If $q=1$ we reproduce Asaeda-Przytycki-Sikora (APS) homology for
links in a thickened annulus. We prove that our homology carries an action of
$\mathcal U_q(\mathfrak{sl}_2)$, which intertwines the action of cobordisms. In
particular, the~quantum annular homology of an $n$-cable admits an action of
the braid group, which commutes with the quantum group action and factors
through the Jones skein relation. This produces a nontrivial invariant for
surfaces knotted in four dimensions. Moreover, a direct computation for torus
links shows that the rank of quantum annular homology groups does depend on the
quantum parameter $q$.


title: Coxeter-biCatalan combinatorics

abstract:
  We pose counting problems related to the various settings for Coxeter-Catalan
combinatorics (noncrossing, nonnesting, clusters, Cambrian). Each problem is to
count "twin" pairs of objects from a corresponding problem in Coxeter-Catalan
combinatorics. We show that the problems all have the same answer, and, for a
given finite Coxeter group W, we call the common solution to these problems the
W-biCatalan number. We compute the W-biCatalan number for all W and take the
first steps in the study of Coxeter-biCatalan combinatorics.


title:
Development Toward a Ground-Based Interferometric Phased Array for Radio
  Detection of High Energy Neutrinos

abstract:
  The in-ice radio interferometric phased array technique for detection of high
energy neutrinos looks for Askaryan emission from neutrinos interacting in
large volumes of glacial ice, and is being developed as a way to achieve a low
energy threshold and a large effective volume at high energies. The technique
is based on coherently summing the impulsive Askaryan signal from multiple
antennas, which increases the signal-to-noise ratio for weak signals. We report
here on measurements and a simulation of thermal noise correlations between
nearby antennas, beamforming of impulsive signals, and a measurement of the
expected improvement in trigger efficiency through the phased array technique.
We also discuss the noise environment observed with an analog phased array at
Summit Station, Greenland, a possible site for an interferometric phased array
for radio detection of high energy neutrinos.


title:
Charge Carrier Concentration Dependence of Encounter-Limited Bimolecular
  Recombination in Phase-Separated Organic Semiconductor Blends

abstract:
  Understanding how the complex intermolecular- and nano-structure present in
organic semiconductor donor-acceptor blends impacts charge carrier motion,
interactions, and recombination behavior is a critical fundamental issue with a
particularly major impact on organic photovoltaic applications. In this study,
kinetic Monte Carlo (KMC) simulations are used to numerically quantify the
complex bimolecular charge carrier recombination behavior in idealized
phase-separated blends. Recent KMC simulations have identified how the
encounter-limited bimolecular recombination rate in these blends deviates from
the often used Langevin model and have been used to construct the new power
mean mobility model. Here, we make a challenging but crucial expansion to this
work by determining the charge carrier concentration dependence of the
encounter-limited bimolecular recombination coefficient. In doing so, we find
that an accurate treatment of the long-range electrostatic interactions between
charge carriers is critical, and we further argue that many previous KMC
simulation studies have used a Coulomb cutoff radius that is too small, which
causes a significant overestimation of the recombination rate. To shed more
light on this issue, we determine the minimum cutoff radius required to reach
an accuracy of less than $\pm10\%$ as a function of the domain size and the
charge carrier concentration and then use this knowledge to accurately quantify
the charge carrier concentration dependence of the recombination rate. Using
these rigorous methods, we finally show that the parameters of the power mean
mobility model are determined by a newly identified dimensionless ratio of the
domain size to the average charge carrier separation distance.


title:
Equation of motion theory for excited states in variational Monte Carlo
  and the Jastrow antisymmetric geminal power in Hilbert space

abstract:
  An equation of motion formalism for excited states in variational Monte Carlo
is derived and a pilot implementation for the Jastrow-modified antisymmetric
geminal power is tested. In single excitations across a range of small
molecules, this combination is shown to be intermediate in accuracy between
configuration interaction singles and equation of motion coupled cluster with
singles and doubles. For double excitations, energy errors are found to be
similar to those for coupled cluster.


title:
Magnetic behavior of Gd3Ru4Al12, a layered compound with a distorted
  Kagome net

abstract:
  The magnetic behavior of the compound, Gd3Ru4Al12, which has been reported to
crystallize in a hexagonal structure about two decades ago, had not been
investigated in the past literature despite interesting structural features
(that is, magnetic layers and triangles as well as Kagome-lattice features
favouring frustrated magnetism) characterizing this compound. We report here
the results of magnetization, heat-capacity, and magnetoresistance studies in
the temperature (T) range 1.8-300 K. The results establish that there is a
long-range magnetic order of an antiferromagnetic type below (TN= ) 18.5 K,
despite a much large value (about 80 K) of paramagnetic Curie temperature with
a positive sign characteristic of ferromagnetic interaction. We attribute this
to geometric frustration. The most interesting finding is that there is an
additional magnetic anomaly below about 55 K before the onset of long range
order in the magnetic susceptibility data. Concurrent with this observation,
the sign of isothermal entropy change remains positive above TN with a broad
peak above TN. This observation indicates the presence of ferromagnetic
clusters before the onset of long range magnetic order. Thus, this compound may
serve as an example for a situation in which magnetic frustration due to
geometrical reasons is faced by competition with such precursor effects. There
is also a reversal of the sign of entropy-change in the curves for lower final
fields (for H less than 30 kOe) on entering into magnetically ordered state
consistent with the entrance into antiferromagnetic state. The
magnetoresistance behavior is consistent with above conclusions.


title:
On the Iteration Complexity of Oblivious First-Order Optimization
  Algorithms

abstract:
  We consider a broad class of first-order optimization algorithms which are
\emph{oblivious}, in the sense that their step sizes are scheduled regardless
of the function under consideration, except for limited side-information such
as smoothness or strong convexity parameters. With the knowledge of these two
parameters, we show that any such algorithm attains an iteration complexity
lower bound of $\Omega(\sqrt{L/\epsilon})$ for $L$-smooth convex functions, and
$\tilde{\Omega}(\sqrt{L/\mu}\ln(1/\epsilon))$ for $L$-smooth $\mu$-strongly
convex functions. These lower bounds are stronger than those in the traditional
oracle model, as they hold independently of the dimension. To attain these, we
abandon the oracle model in favor of a structure-based approach which builds
upon a framework recently proposed in (Arjevani et al., 2015). We further show
that without knowing the strong convexity parameter, it is impossible to attain
an iteration complexity better than
$\tilde{\Omega}\left((L/\mu)\ln(1/\epsilon)\right)$. This result is then used
to formalize an observation regarding $L$-smooth convex functions, namely, that
the iteration complexity of algorithms employing time-invariant step sizes must
be at least $\Omega(L/\epsilon)$.


title:
Vertex-imprimitive symmetric graphs with exactly one edge between any
  two distinct blocks

abstract:
  A graph $\Gamma$ is called $G$-symmetric if it admits $G$ as a group of
automorphisms acting transitively on the set of ordered pairs of adjacent
vertices. We give a classification of $G$-symmetric graphs $\Gamma$ with
$V(\Gamma)$ admitting a nontrivial $G$-invariant partition $\mathcal{B}$ such
that there is exactly one edge of $\Gamma$ between any two distinct blocks of
$\mathcal{B}$. This is achieved by giving a classification of $(G,
2)$-point-transitive and $G$-block-transitive designs $\mathcal{D}$ together
with $G$-orbits $\Omega$ on the flag set of $\mathcal{D}$ such that $G_{\sigma,
L}$ is transitive on $L \setminus \{\sigma\}$ and $L \cap N = \{\sigma\}$ for
distinct $(\sigma, L), (\sigma, N) \in \Omega$, where $G_{\sigma, L}$ is the
setwise stabilizer of $L$ in the stabilizer $G_{\sigma}$ of $\sigma$ in $G$.
Along the way we determine all imprimitive blocks of $G_{\sigma}$ on $V
\setminus \{\sigma\}$ for every $2$-transitive group $G$ on a set $V$, where
$\sigma \in V$.


title: Proving Nontrivial Topology of Pure Bismuth by Quantum Confinement

abstract:
  The topology of pure Bi is controversial because of its very small ($\sim$10
meV) band gap. Here we perform high-resolution angle-resolved photoelectron
spectroscopy measurements systematically on 14$-$202 bilayers Bi films. Using
high-quality films, we succeed in observing quantized bulk bands with energy
separations down to $\sim$10 meV. Detailed analyses on the phase shift of the
confined wave functions precisely determine the surface and bulk electronic
structures, which unambiguously show nontrivial topology. The present results
not only prove the fundamental property of Bi but also introduce a capability
of the quantum-confinement approach.


title: The Dirichlet problem for the constant mean curvature equation in Sol_3

abstract:
  A version of the Jenkins-Serrin theorem for the existence of CMC graphs over
bounded domains with infinite boundary data in Sol$_3$ is proved. Moreover, we
construct examples of admissible domains where the results may be applied.


title: On main eigenvalues of certain graphs

abstract:
  An eigenvalue of the adjacency matrix of a graph is said to be \emph{main} if
the all-1 vector is not orthogonal to the associated eigenspace. In this work,
we approach the main eigenvalues of some graphs. The graphs with exactly two
main eigenvalues are considered and a relation between those main eigenvalues
is presented. The particular case of harmonic graphs is analyzed and they are
characterized in terms of their main eigenvalues without any restriction on its
combinatorial structure. We give a necessary and sufficient condition for a
graph $G$ to have $-1-\lambda_{\min}$ as an eigenvalue of its complement, where
$\lambda_{\min}$ denotes the least eigenvalue of $G$. Also, we prove that among
connected bipartite graphs, $K_{r,r}$ is the unique graph for which the index
of the complement is equal to $-1-\lambda_{\min}$. Finally, we characterize all
paths and all double stars (trees with diameter three) for which the smallest
eigenvalue is non-main. Main eigenvalues of paths and double stars are
identified.


title: Time, classical and quantum

abstract:
  We propose a new point of view regarding the problem of time in quantum
mechanics, based on the idea of replacing the usual time operator $\mathbf{T}$
with a suitable real-valued function $T$ on the space of physical states. The
proper characterization of the function $T$ relies on a particular relation
with the dynamical evolution of the system rather than with the infinitesimal
generator of the dynamics (Hamiltonian). We first consider the case of
classical Hamiltonian mechanics, where observables are functions on phase space
and the tools of differential geometry can be applied. The idea is then
extended to the case of the unitary evolution of pure states of finite-level
quantum systems by means of the geometric formulation of quantum mechanics. It
is found that $T$ is a function on the space of pure states which is not
associated to any self-adjoint operator. The link between $T$ and the dynamical
evolution is interpreted as defining a simultaneity relation for the states of
the system with respect to the dynamical evolution itself. It turns out that
different dynamical evolutions lead to different notions of simultaneity, i.e.,
the notion of simultaneity is a dynamical notion.


title: A Novel Framework for Electronic Global Health Record Access

abstract:
  When most patients visit physicians in a clinic or a hospital, they are asked
about their medical history and related medical tests' results which might not
exist or might simply have been lost over time. In emergency situations, many
patients suffer or sadly die because of lack of pertinent medical information.
Patient's Health information (PHI) saved by Electronic Medical Record (EMR)
could be accessible only by a hospital using their EMR system. Furthermore,
Personal Health Record (PHR) information cannot be solely relied on since it is
controlled solely by patients. This paper introduces a novel framework for
accessing, sharing, and controlling the medical records for patients and their
physicians globally, while patients' PHI are securely stored and their privacy
is taken into consideration. Based on the framework, a proof of concept
prototype is implemented. Preliminary performance evaluation results indicate
the validity and viability of the proposed framework.


title:
Synthetic extinction maps around intermediate-mass black holes in
  Galactic globular clusters

abstract:
  During the last decades, much effort has been devoted to explain the
discrepancy between the amount of intracluster medium (ICM) estimated from
stellar evolution theories and that emerging from observations in globular
clusters (GCs). One possible scenario is the accretion of this medium by an
intermediate-mass black hole (IMBH) at the centre of the cluster. In this work,
we aim at modelling the cluster colour-excess profile as a tracer of the ICM
density, both with and without an IMBH. Comparing the profiles with
observations allows us to test the existence of IMBHs and their possible role
in the cleansing of the ICM. We derive the intracluster density profiles from
hydrodynamical models of accretion onto a central IMBH in a GC and we determine
the corresponding dust density. This model is applied to a list of 25 Galactic
GCs. We find that central IMBHs decrease the ICM by several orders of
magnitude. In a subset of 9 clusters, the absence of the black hole combined
with a low intracluster medium temperature would be at odds with present gas
mass content estimations. As a result, we conclude that IMBHs are an effective
cleansing mechanism of the ICM of GCs. We construct synthetic extinction maps
for M 62 and {\omega} Cen, two clusters in the small subset of 9 with observed
2D extinction maps. We find that under reasonable assumptions regarding the
model parameters, if the gas temperature in M 62 is close to 8000 K, an IMBH
needs to be invoked. Further ICM observations regarding both the gas and dust
in GCs could help to settle this issue.


title: Spatial distribution of entanglements in thin free-standing films

abstract:
  We simulate entangled linear polymers in free-standing thin film geometries
where the confining dimension is on the same scale or smaller than the bulk
chain dimensions. We compare both film-averaged and layer-resolved, spatially
inhomogeneous measures of the polymer structure and entanglement network with
theoretical models. We find that these properties are controlled by the ratio
of both chain- and entanglement-strand length scales to the film thickness.
While the film-averaged entanglement properties can be accurately predicted, we
identify outstanding challenges in understanding the spatially resolved
character of the heterogeneities in the entanglement network, particularly when
the scale of both the entanglement strand and the chain end-to-end vector is
comparable to or smaller than the film thickness.


title: Unbounded Norm Convergence in Banach Lattices

abstract:
  A net $(x_\alpha)$ in a vector lattice $X$ is unbounded order convergent to
$x \in X$ if $\lvert x_\alpha - x\rvert \wedge u$ converges to $0$ in order for
all $u\in X_+$. This convergence has been investigated and applied in several
recent papers by Gao et al. It may be viewed as a generalization of almost
everywhere convergence to general vector lattices. In this paper, we study a
variation of this convergence for Banach lattices. A net $(x_\alpha)$ in a
Banach lattice $X$ is unbounded norm convergent to $x$ if $\lVert\lvert
x_\alpha - x\rvert \wedge u\rVert\to 0$ for all $u\in X_+$. We show that this
convergence may be viewed as a generalization of convergence in measure. We
also investigate its relationship with other convergences.


title:
Sublattice signatures of transitions in a $\mathcal{PT}$-symmetric dimer
  lattice

abstract:
  Lattice models with non-hermitian, parity and time-reversal ($\mathcal{PT}$)
symmetric Hamiltonians, realized most readily in coupled optical systems, have
been intensely studied in the past few years. A $\mathcal{PT}$-symmetric dimer
lattice consists of dimers with intra-dimer coupling $\nu$, inter-dimer
coupling $\nu'$, and balanced gain and loss potentials $\pm i\gamma$ within
each dimer. This model undergoes two independent transitions, namely a
$\mathcal{PT}$-breaking transition and a topological transition. We numerically
and analytically investigate the signatures of these transitions in the
time-evolution of states that are initially localized on the gain-site or the
loss-site.


title:
A unified model for the time variability of the Crab: the dispersion
  measure variation and the $\gamma$-ray flare of the nebula

abstract:
  The Crab pulsar and its nebula are very luminous and variable. Since 1982,
random fluctuations of the dispersion measure (DM) have been recorded. Also in
2011, Fermi-LAT telescope detected $\gamma$-ray flux variation of the Crab
nebula. No correlation between these phenomena have considered although their
fluctuating patterns look similar. We propose a model which connects the DM and
the Crab nebula $\gamma$-ray flux fluctuation, motivated by recently reported
correlation between the braking index and the DM variability. Considering
electrons within the inner shock region of the nebula produced in breaking
index change events, we can explain both the DM enhancement and the
$\gamma$-ray flare in a simple way.


title:
A Comparison and Joint Analysis of Sunyaev-Zel'dovich Effect
  Measurements from Planck and Bolocam for a set of 47 Massive Galaxy Clusters

abstract:
  We measure the SZ signal toward a set of 47 clusters with a median mass of
$9.5 \times 10^{14}$ M$_{\odot}$ and a median redshift of 0.40 using data from
Planck and the ground-based Bolocam receiver. When Planck XMM-like masses are
used to set the scale radius $\theta_{\textrm{s}}$, we find consistency between
the integrated SZ signal, $Y_{\textrm{5R500}}$, derived from Bolocam and Planck
based on gNFW model fits using A10 shape parameters, with an average ratio of
$1.069 \pm 0.030$ (allowing for the $\simeq 5$% Bolocam flux calibration
uncertainty). We also perform a joint fit to the Bolocam and Planck data using
a modified A10 model with the outer logarithmic slope $\beta$ allowed to vary,
finding $\beta = 6.13 \pm 0.16 \pm 0.76$ (measurement error followed by
intrinsic scatter). In addition, we find that the value of $\beta$ scales with
mass and redshift according to $\beta \propto M^{0.077 \pm 0.026} \times
(1+z)^{-0.06 \pm 0.09}$. This mass scaling is in good agreement with recent
simulations. We do not observe the strong trend of $\beta$ with redshift seen
in simulations, though we conclude that this is most likely due to our sample
selection. Finally, we use Bolocam measurements of $Y_{500}$ to test the
accuracy of the Planck completeness estimate. We find consistency, with the
actual number of Planck detections falling approximately $1 \sigma$ below the
expectation from Bolocam. We translate this small difference into a constraint
on the the effective mass bias for the Planck cluster cosmology results, with
$(1-b) = 0.93 \pm 0.06$.


title:
An improved Constant-Factor Approximation Algorithm for Planar
  Visibility Counting Problem

abstract:
  Given a set $S$ of $n$ disjoint line segments in $\mathbb{R}^{2}$, the
visibility counting problem (VCP) is to preprocess $S$ such that the number of
segments in $S$ visible from any query point $p$ can be computed quickly. This
problem can trivially be solved in logarithmic query time using $O(n^{4})$
preprocessing time and space. Gudmundsson and Morin proposed a 2-approximation
algorithm for this problem with a tradeoff between the space and the query
time. They answer any query in $O_{\epsilon}(n^{1-\alpha})$ with
$O_{\epsilon}(n^{2+2\alpha})$ of preprocessing time and space, where $\alpha$
is a constant $0\leq \alpha\leq 1$, $\epsilon > 0$ is another constant that can
be made arbitrarily small, and $O_{\epsilon}(f(n))=O(f(n)n^{\epsilon})$.
  In this paper, we propose a randomized approximation algorithm for VCP with a
tradeoff between the space and the query time. We will show that for an
arbitrary constants $0\leq \beta\leq \frac{2}{3}$ and $0<\delta <1$, the
expected preprocessing time, the expected space, and the query time of our
algorithm are $O(n^{4-3\beta}\log n)$, $O(n^{4-3\beta})$, and
$O(\frac{1}{\delta^3}n^{\beta}\log n)$, respectively. The algorithm computes
the number of visible segments from $p$, or $m_p$, exactly if $m_p\leq
\frac{1}{\delta^3}n^{\beta}\log n$. Otherwise, it computes a
$(1+\delta)$-approximation $m'_p$ with the probability of at least
$1-\frac{1}{\log n}$, where $m_p\leq m'_p\leq (1+\delta)m_p$.


title: C*-envelopes of tensor algebras arising from stochastic matrices

abstract:
  In this paper we study the C*-envelope of the (non-self-adjoint) tensor
algebra associated via subproduct systems to a finite irreducible stochastic
matrix $P$. Firstly, we identify the boundary representations of the tensor
algebra inside the Toeplitz algebra, also known as its non-commutative Choquet
boundary. As an application, we provide examples of C*-envelopes that are not
*-isomorphic to either the Toeplitz algebra or the Cuntz-Pimsner algebra. This
characterization required a new proof for the fact that the Cuntz-Pimsner
algebra associated to $P$ is isomorphic to $C(\mathbb{T}, M_d(\mathbb{C}))$,
filling a gap in a previous paper. We then proceed to classify the C*-envelopes
of tensor algebras of stochastic matrices up to *-isomorphism and stable
isomorphism, in terms of the underlying matrices. This is accomplished by
determining the K-theory of these C*-algebras and by combining this information
with results due to Paschke and Salinas in extension theory. This
classification is applied to provide a clearer picture of the various
C*-envelopes that can land between the Toeplitz and the Cuntz-Pimsner algebras.


title: Controllable light capsules employing modified Bessel-Gauss beams

abstract:
  We report, in theory and experiment, on a novel class of controlled light
capsules with nearly perfect darkness, directly employing intrinsic properties
of modified Bessel-Gauss beams. These beams are able to naturally create
three-dimensional bottle-shaped region during propagation as long as the
parameters are properly chosen. Remarkably, the optical bottle can be
controlled to demonstrate various geometries through tuning the beam
parameters, thereby leading to an adjustable light capsule. We provide a
detailed insight into the theoretical origin and characteristics of the light
capsule derived from modified Bessel-Gauss beams. Moreover, a binary digital
micromirror device (DMD) based scheme is first employed to shape the bottle
beams by precise amplitude and phase manipulation. Further, we demonstrate
their ability for optical trapping of core-shell magnetic microparticles, which
play a particular role in biomedical research, with holographic optical
tweezers. Therefore, our observations provide a new route for generating and
controlling bottle beams and will widen the potentials for micromanipulation of
absorbing particles, aerosols or even individual atoms.


title: Magnetic properties of single nanomagnets: EMCD on FePt nanoparticles

abstract:
  Energy-loss magnetic chiral dichroism (EMCD) allows for the quantification of
magnetic properties of materials at the nanometer scale. It is shown that with
the support of simulations that help to identify the optimal conditions for a
successful experiment and upon implementing measurement routines that
effectively reduce the noise floor, EMCD measurements can be pushed towards
quantitative magnetic measurements even on individual nanoparticles. With this
approach, the ratio of orbital to spin magnetic moments for the Fe atoms in a
single L$1_0$ ordered FePt nanoparticle is determined to be ${m_l}/{m_s} = 0.08
\pm 0.02$. This finding is in good quantitative agreement with the results of
XMCD ensemble measurements.


title: ARRIVAL: A zero-player graph game in NP $\cap$ coNP

abstract:
  Suppose that a train is running along a railway network, starting from a
designated origin, with the goal of reaching a designated destination. The
network, however, is of a special nature: every time the train traverses a
switch, the switch will change its position immediately afterwards. Hence, the
next time the train traverses the same switch, the other direction will be
taken, so that directions alternate with each traversal of the switch. Given a
network with origin and destination, what is the complexity of deciding whether
the train, starting at the origin, will eventually reach the destination? It is
easy to see that this problem can be solved in exponential time, but we are not
aware of any polynomial-time method. In this short paper, we prove that the
problem is in NP $\cap$ coNP. This raises the question whether we have just
failed to find a (simple) polynomial-time solution, or whether the complexity
status is more subtle, as for some other well-known (two-player) graph games.


title:
On Storage Allocation for Maximum Service Rate in Distributed Storage
  Systems

abstract:
  Storage allocation affects important performance measures of distributed
storage systems. Most previous studies on the storage allocation consider its
effect separately either on the success of the data recovery or on the service
rate (time) where it is assumed that no access failure happens in the system.
In this paper, we go one step further and incorporate the access model and the
success of data recovery into the service rate analysis. In particular, we
focus on quasi-uniform storage allocation and provide a service rate analysis
for both fixed-size and probabilistic access models at the nodes. Using this
analysis, we then show that for the case of exponential waiting time
distribution at individuals storage nodes, minimal spreading allocation results
in the highest system service rate for both access models. This means that for
a given storage budget, replication provides a better service rate than a coded
storage solution.


title:
Existence of a phase transition of the interchange process on the
  Hamming graph

abstract:
  The interchange process on a finite graph is obtained by placing a particle
on each vertex of the graph, then at rate 1, selecting an edge uniformly at
random and swapping the two particles at either end of this edge. In this paper
we develop new techniques to show the existence of a phase transition of the
interchange process on the 2-dimensional Hamming graph. We show that in the
subcritical phase, all of the cycles of the process have length $O(\log n)$,
whereas in the supercritical phase a positive density of vertices lie in cycles
of length at least $n^{2-\varepsilon}$ for any $\varepsilon>0$.


title: Graph homomorphisms and components of quotient graphs

abstract:
  We study how the number $c(X)$ of components of a graph $X$ can be expressed
through the number and properties of the components of a quotient graph
$X/\sim.$ We partially rely on classic qualifications of graph homomorphisms
such as locally constrained homomorphisms and on the concept of equitable
partition and orbit partition. We introduce the new definitions of
pseudo-covering homomorphism and of component equitable partition, exhibiting
interesting inclusions among the various classes of considered homomorphisms.
As a consequence, we find a procedure for computing $c(X)$ when the projection
on the quotient $X/\sim$ is pseudo-covering. That procedure becomes
particularly easy to handle when the partition corresponding to $X/\sim$ is an
orbit partition.


title: Dynamical analysis for a vector-like dark energy

abstract:
  In this paper we perform a dynamical analysis for a vector field as a
candidate for the dark energy, in the presence of a barothropic fluid. The
vector is one component of the so-called cosmic triad, which is a set of three
identical copies of an abelian field pointing mutually in orthogonal
directions. In order to generalize the analysis, we also assumed the
interaction between dark energy and the barotropic fluid, with a
phenomenological coupling. Both matter and dark energy eras can be successfully
described by the critical points, indicating that the dynamical system theory
is a viable tool to analyze asymptotic states of such cosmological models.


title: Global Gauge Symmetries, Risk-Free Portfolios, and the Risk-Free Rate

abstract:
  We define risk-free portfolios using three gauge invariant differential
operators that require such portfolios to be insensitive to price changes, to
be self-financing, and to produce a zero real return so there are no risk-free
profits. This definition identifies the risk-free rate as the return of an
infinitely diversified portfolio rather than as an arbitrary external
parameter. The risk-free rate measures the rate of global price rescaling,
which is a gauge symmetry of economies. We explore the properties of risk-free
rates, rederive the Black Scholes equation with a new interpretation of the
risk-free rate parameter as a that background gauge field, and discuss gauge
invariant discounting of cash flows.


title: Non-split and split deformations of AdS_5

abstract:
  The eta-deformation of the AdS_5 x S^5 superstring depends on a non-split r
matrix for the superalgebra psu(2,2|4). Much of the investigation into this
model has considered one particular choice, however there are a number of
inequivalent alternatives. This is also true for the bosonic sector of the
theory with su(2,2), the isometry algebra of AdS_5, admitting one split and
three non-split r matrices. In this article we explore these r matrices and the
corresponding geometries. We investigate their contraction limits, comment on
supergravity backgrounds and demonstrate their relation to gauged-WZW
deformations. We then extend the three non-split cases to AdS_5 x S^5 and
compute four separate bosonic two-particle tree-level S-matrices based on
inequivalent BMN-type light-cone gauges. The resulting S-matrices, while
different, are related by momentum-dependent one-particle changes of basis.


title:
Increasing cognitive-emotional flexibility with meditation and hypnosis:
  The cognitive neuroscience of de-automatization

abstract:
  Meditation and hypnosis both aim to facilitate cognitive-emotional
flexibility, i.e., the "de-automatization" of thought and behavior. However,
little research or theory has addressed how internal thought patterns might
change after such interventions, even though alterations in the internal flow
of consciousness may precede externally observable changes in behavior. This
chapter outlines three mechanisms by which meditation or hypnosis might alter
or reduce automatic associations and elaborations of spontaneous thought: by an
overall reduction of the chaining of thoughts into an associative stream; by
de-automatizing and diversifying the content of thought chains (i.e.,
increasing thought flexibility or variety); and, finally, by re-automatizing
chains of thought along desired or valued paths (i.e., forming new, voluntarily
chosen mental habits). The authors discuss behavioral and cognitive
neuroscientific evidence demonstrating the influence of hypnosis and meditation
on internal cognition and highlight the putative neurobiological basis, as well
as potential benefits, of these forms of de-automatization.


title: On jordanian deformations of AdS_5 and supergravity

abstract:
  We consider various homogeneous Yang-Baxter deformations of the AdS_5 x S^5
superstring that can be obtained from the eta-deformed superstring and related
models by singular boosts. The jordanian deformations we obtain in this way
behave similarly to the eta-deformed model with regard to supergravity: T
dualizing the classical sigma model it is possible to find corresponding
solutions of supergravity, which, however, have dilatons that prevent T
dualizing back. Hence the backgrounds of these jordanian deformations are not
solutions of supergravity. Still, they do satisfy a set of recently found
modified supergravity equations which implies that the corresponding sigma
models are scale invariant. The abelian models that we obtain by singular
boosts do directly correspond to solutions of supergravity. In addition to our
main results we consider contraction limits of our main example, which do
correspond to supergravity solutions.


title:
The relationships between message passing, pairwise, Kermack-McKendrick
  and stochastic SIR epidemic models

abstract:
  We consider a very general stochastic model for an SIR epidemic on a network
which allows an individual's infectious period, and the time it takes to
contact each of its neighbours after becoming infected, to be correlated. We
write down the message passing system of equations for this model and prove,
for the first time, that it has a unique feasible solution. We also generalise
an earlier result by proving that this solution provides a rigorous upper bound
for the expected epidemic size (cumulative number of infection events) at any
fixed time $t>0$.
  We specialise these results to a homogeneous special case where the graph
(network) is symmetric. The message passing system here reduces to just four
equations. We prove that cycles in the network inhibit the spread of infection,
and derive important epidemiological results concerning the final epidemic size
and threshold behaviour for a major outbreak. For Poisson contact processes,
this message passing system is equivalent to a non-Markovian pair approximation
model, which we show has well-known pairwise models as special cases.
  We show further that a sequence of message passing systems, starting with the
homogeneous one just described, converges to the deterministic
Kermack-McKendrick equations for this stochastic model. For Poisson contact and
recovery, we show that this convergence is monotone, from which it follows that
the message passing system (and hence also the pairwise model) here provides a
better approximation to the expected epidemic size at time $t>0$ than the
Kermack-McKendrick model.

categories: q-bio.PE cond-mat.stat-mech math.PR physics.soc-ph


title:
Polarization dependence of photo-mechanical behavior of monodomain
  liquid crystal polymeric materials

abstract:
  Polarization dependence of opto-mechanical behavior of monodomain
photochromic glassy liquid crystal (LC) polymers under polarized ultraviolet
light (PUV) is studied. Trans-cis photo-isomerization is generally known to be
most intense at 'parallel illumination' (polarization parallel to LC director),
as light-medium interactions are active when polarization aligns with
trainsition dipole moment. We show that at parallel illumination though cis
isomers are converted from trans the most near surface, they can be the least
below certain light propagation depth. Membrane force, an average effect of
trans-cis conversion over propagation depths, shows a monotonic polarization
dependence, i.e. maximum at parallel illumination, which agrees well with
experiment [1]. However, under strong illumination, cis
fraction/photo-contraction distribution through depths shows deep penetration,
switching over the polarization dependence in photo-moment, which is related to
photo-contraction gradient ---- photo-moment can be maximum at 'perpendicular
illumination' (polarization perpendicular to director) under strong light. We
give both intuitive explanation and analytical demonstration in thin strip
limit for the switchover.


title: View Synthesis by Appearance Flow

abstract:
  We address the problem of novel view synthesis: given an input image,
synthesizing new images of the same object or scene observed from arbitrary
viewpoints. We approach this as a learning task but, critically, instead of
learning to synthesize pixels from scratch, we learn to copy them from the
input image. Our approach exploits the observation that the visual appearance
of different views of the same instance is highly correlated, and such
correlation could be explicitly learned by training a convolutional neural
network (CNN) to predict appearance flows -- 2-D coordinate vectors specifying
which pixels in the input view could be used to reconstruct the target view.
Furthermore, the proposed framework easily generalizes to multiple input views
by learning how to optimally combine single-view predictions. We show that for
both objects and scenes, our approach is able to synthesize novel views of
higher perceptual quality than previous CNN-based techniques.


title:
Excluding blowup at zero points of the potential by means of
  Liouville-type theorems

abstract:
  We prove a local version of a (global) result of Merle and Zaag about ODE
behavior of solutions near blowup points for subcritical nonlinear heat
equations. As an application, for the equation $u_t= \Delta u+V(x)f(u)$, we
rule out the possibility of blowup at zero points of the potential $V$ for
monotone in time solutions when $f(u)\sim u^p$ for large $u$, both in the
Sobolev subcritical case and in the radial case. This solves a problem left
open in previous work on the subject. Suitable Liouville-type theorems play a
crucial role in the proofs.


title: Survey on log-normally distributed market-technical trend data

abstract:
  In this survey, a short introduction in the recent discovery of log-normally
distributed market-technical trend data will be given. The results of the
statistical evaluation of typical market-technical trend variables will be
presented. It will be shown that the log-normal assumption fits better to
empirical trend data than to daily returns of stock prices. This enables to
mathematically evaluate trading systems depending on such variables. In this
manner, a basic approach to an anti cyclic trading system will be given as an
example.


title: COCO: Performance Assessment

abstract:
  We present an any-time performance assessment for benchmarking numerical
optimization algorithms in a black-box scenario, applied within the COCO
benchmarking platform. The performance assessment is based on runtimes measured
in number of objective function evaluations to reach one or several quality
indicator target values. We argue that runtime is the only available measure
with a generic, meaningful, and quantitative interpretation. We discuss the
choice of the target values, runlength-based targets, and the aggregation of
results by using simulated restarts, averages, and empirical distribution
functions.


title: Predictions for bottomonia suppression in 5.023 TeV Pb-Pb collisions

abstract:
  We compute the suppression of the bottomonia states Upsilon(1S), Upsilon(2S),
Upsilon(3S), chi_b(1P), chi_b(2P), and chi_b(3P) states in Large Hadron
Collider (LHC) sqrt(s_NN)) = 5.023 TeV Pb-Pb collisions. For the background
evolution we use 3+1d anisotropic hydrodynamics with conditions extrapolated
from sqrt(s_NN) = 2.76 TeV and we self-consistently compute bottomonia decay
rates including non-equilibrium corrections to the interaction potential. For
our final results, we make predictions for R_AA as function of centrality,
rapidity, and p_T for the Upsilon(1S) and Upsilon(2S) states, including feed
down effects. In order to assess the dependence on some of the model
assumptions, we vary the shear viscosity-to-entropy density ratio, 4 pi eta/s =
(1, 2, 3), and the initial momentum-space anisotropy parameter, xi_0 = (0, 10,
50), while holding the total light hadron multiplicity fixed.


title:
Finite size effects. The averaged eigenvalue density of Wigner random
  sign real symmetric matrices

abstract:
  Nowadays, strict finite size effects must be taken into account in condensed
matter problems when treated through models based on lattices or graphs. On the
other hand, the cases of directed bonds or links are known as highly relevant,
in topics ranging from ferroelectrics to quotation networks. Combining these
two points leads to examine finite size random matrices. To obtain basic
materials properties, the Green function associated to the matrix has to be
calculated. In order to obtain the first finite size correction a perturbative
scheme is hereby developed within the framework of the replica method. The
averaged eigenvalue spectrum and the corresponding Green function of Wigner
random sign real symmetric N x N matrices to order 1/N are in fine obtained
analytically. Related simulation results are also presented. The comparison
between the analytical formulae and finite size matrices numerical
diagonalization results exhibits an excellent agreement, confirming the
correctness of the first order finite size expression.


title:
Liouville quantum gravity and the Brownian map II: geodesics and
  continuity of the embedding

abstract:
  We endow the $\sqrt{8/3}$-Liouville quantum gravity sphere with a metric
space structure and show that the resulting metric measure space agrees in law
with the Brownian map. Recall that a Liouville quantum gravity sphere is a
priori naturally parameterized by the Euclidean sphere ${\mathbf S}^2$.
Previous work in this series used quantum Loewner evolution (QLE) to construct
a metric $d_{\mathcal Q}$ on a countable dense subset of ${\mathbf S}^2$. Here
we show that $d_{\mathcal Q}$ a.s. extends uniquely and continuously to a
metric $\bar{d}_{\mathcal Q}$ on all of ${\mathbf S}^2$. Letting $d$ denote the
Euclidean metric on ${\mathbf S}^2$, we show that the identity map between
$({\mathbf S}^2, d)$ and $({\mathbf S}^2, \bar{d}_{\mathcal Q})$ is a.s.
H\"older continuous in both directions. We establish several other properties
of $({\mathbf S}^2, \bar{d}_{\mathcal Q})$, culminating in the fact that (as a
random metric measure space) it agrees in law with the Brownian map. We
establish analogous results for the Brownian disk and plane. Our proofs involve
new estimates on the size and shape of QLE balls and related quantum surfaces,
as well as a careful analysis of $({\mathbf S}^2, \bar{d}_{\mathcal Q})$
geodesics.


title: Combinatorial Entanglement

abstract:
  We present new combinatorial objects, which we call grid-labelled graphs, and
show how these can be used to represent the quantum states arising in a
scenario which we refer to as the faulty emitter scenario: we have a machine
designed to emit a particular quantum state on demand, but which can make an
error and emit a different one. The device is able to produce a list of
candidate states which can be used as a kind of debugging information for
testing entanglement. By reformulating the Peres-Horodecki and matrix
realignment criteria we are able to capture some characteristic features of
entanglement: we construct new bound entangled states, and demonstrate the
limitations of matrix realignment. We show how the notion of LOCC is related to
a generalisation of the graph isomorphism problem. We give a simple proof that
asymptotically almost surely, grid-labelled graphs associated to very sparse
density matrices are entangled. We develop tools for enumerating grid-labelled
graphs that satisfy the Peres-Horodecki criterion up to a fixed number of
vertices, and propose various computational problems for these objects, whose
complexity remains an open problem. The proposed mathematical framework also
suggests new combinatorial and algebraic ways for describing the structure of
graphs.


title:
An analytical model for the influence of contact resistance on
  thermoelectric efficiency

abstract:
  An analytical model is presented that can account for both electrical and hot
and cold thermal contact resistances when calculating the efficiency of a
thermoelectric generator. The model is compared to a numerical model of a
thermoelectric leg, for 16 different thermoelectric materials, as well as the
analytical models of Ebling et. al. (2010) and Min \& Rowe (1992). The model
presented here is shown to accurately calculate the efficiency for all systems
and all contact resistances considered, with an average difference in
efficiency between the numerical model and the analytical model of
$-0.07\pm0.35$ pp. This makes the model more accurate than previously published
models. The maximum absolute difference in efficiency between the analytical
model and the numerical model is 1.14 pp for all materials and all contact
resistances considered.


title:
Perturbative Dynamics of Stationary States in Nonlinear Parity-Time
  Symmetric Coupler

abstract:
  We investigate the nonlinear parity-time (PT) symmetric coupler from a
dynamical perspective. As opposed to linear PT-coupler where the PT threshold
dictates the evolutionary characteristics of optical power in the two
waveguides, in a nonlinear coupler, the PT threshold governs the existence of
stationary points. We have found that the stability of the ground state
undergoes a phase transition when the gain/loss coefficient is increased from
zero to beyond the PT threshold. Moreover, we found that instabilities in
initial conditions can lead to aperiodic oscillations as well as exponential
growth and decay of optical power. At the PT threshold, we observed the
existence of a stable attractor under the influence of fluctuating gain/loss
coefficient. Phase plane analysis has shown us the presence of a toroidal
chaotic attractor. The chaotic dynamics can be controlled by a judicious choice
of the waveguide parameters.