title: Half-BPS half-BPS twist two at four loops in N=4 SYM

abstract:
  We consider a double OPE limit of the planar four-point function of stress
tensor multiplets in N = 4 SYM theory. Loop integrands for this correlator have
been constructed to very high order, but the corresponding integrals are
explicitly known only up to three loops. Fortunately, the double coincidence
limit of the four-loop integrals can be found by the method of expansion by
regions, which reduces the problem of computing the four-point integrals to the
evaluation of a large set of massless propagator integrals. These can in turn
be evaluated by IBP reduction.
  The OPE limit of the stress tensor four-point function allows us to extract
the (square of the) three-point couplings between two stress tensor multiplets
and one twist two operator in the 20' of SU(4). The latest available IBP
software accomplishes this task up to and including spin 8. With the data
obtained we hope to further the development of the recent integrable systems
picture for correlation functions.


title: A Faster Approximation Algorithm for the Gibbs Partition Function

abstract:
  We consider the problem of estimating the partition function $Z(\beta)=\sum_x
\exp(-\beta(H(x))$ of a Gibbs distribution with a Hamilton $H(\cdot)$, or more
precisely the logarithm of the ratio $q=\ln Z(0)/Z(\beta)$. It has been
recently shown how to approximate $q$ with high probability assuming the
existence of an oracle that produces samples from the Gibbs distribution for a
given parameter value in $[0,\beta]$. The current best known approach due to
Huber [9] uses $O(q\ln n\cdot[\ln q + \ln \ln n+\varepsilon^{-2}])$ oracle
calls on average where $\varepsilon$ is the desired accuracy of approximation
and $H(\cdot)$ is assumed to lie in $\{0\}\cup[1,n]$. We improve the complexity
to $O(q\ln n\cdot\varepsilon^{-2})$ oracle calls. We also show that the same
complexity can be achieved if exact oracles are replaced with approximate
sampling oracles that are within $O(\frac{\varepsilon^2}{q\ln n})$ variation
distance from exact oracles. Finally, we prove a lower bound of $\Omega(q\cdot
\varepsilon^{-2})$ oracle calls under a natural model of computation.


title: Generating Synthetic Data for Text Recognition

abstract:
  Generating synthetic images is an art which emulates the natural process of
image generation in a closest possible manner. In this work, we exploit such a
framework for data generation in handwritten domain. We render synthetic data
using open source fonts and incorporate data augmentation schemes. As part of
this work, we release 9M synthetic handwritten word image corpus which could be
useful for training deep network architectures and advancing the performance in
handwritten word spotting and recognition tasks.


title: WASP-86b and WASP-102b: super-dense versus bloated planets

abstract:
  We report the discovery of two transiting planetary systems: a super dense,
sub-Jupiter mass planet WASP-86b (\mpl\ = 0.82 $\pm$ 0.06 \mj, \rpl\ = 0.63
$\pm$ 0.01 \rj), and a bloated, Saturn-like planet WASP-102b (\mpl\ = 0.62
$\pm$ 0.04 \mj, \rpl\=1.27 $\pm$ 0.03 \rj). They orbit their host star every
$\sim$5.03, and $\sim$2.71 days, respectively. The planet hosting WASP-86 is a
F7 star (\teff\ = 6330$\pm$110 K, \feh\ = $+$0.23 $\pm$ 0.14 dex, and age
$\sim$0.8--1~Gyr), WASP-102 is a G0 star (\teff\ = 5940$\pm$140 K, \feh\ =
$-$0.09$\pm$ 0.19 dex, and age $\sim$1~Gyr). These two systems highlight the
diversity of planetary radii over similar masses for giant planets with masses
between Saturn and Jupiter. WASP-102b shows a larger than model-predicted
radius, indicating that the planet is receiving a strong incident flux which
contributes to the inflation of its radius. On the other hand, with a density
of $\rho_{pl}$ = 3.24$\pm$~0.3~$\rho_{jup}$, WASP-86b is the densest gas giant
planet among planets with masses in the range 0.05 $<M$_{pl}$<$ 2.0 \mj. With a
stellar mass of 1.34 M$_{\odot}$ and \feh = $+$0.23 dex, WASP-86 could host
additional massive and dense planets given that its protoplanetary disc is
expected to also have been enriched with heavy elements. In order to match
WASP-86b's density, an extrapolation of theoretical models predicts a planet
composition of more than 80\% in heavy elements (whether confined in a core or
mixed in the envelope). This fraction corresponds to a core mass of
approximately 210\me\ for WASP-86b's mass of \mpl$\sim$260\,\me. Only planets
with masses larger than about 2\mj\ have larger densities than that of
WASP-86b, making it exceptional in its mass range.


title: Index Theory and the Baum-Connes conjecture

abstract:
  These notes are based on lectures on index theory, topology, and operator
algebras at the "School on High Dimensional Manifold Theory" at the ICTP in
Trieste, and at the Seminari di Geometria 2002 in Bologna. We describe how
techniques coming from the theory of operator algebras, in particular
$C^*$-algebras, can be used to study manifolds. Operator algebras are
extensively studied in their own right. We will focus on the basic definitions
and properties, and on their relevance to the geometry and topology of
manifolds. The link between topology and analysis is provided by index
theorems. Starting with the classical Atiyah-Singer index theorem, we will
explain several index theorems in detail.
  Our point of view will be in particular, that an index lives in a canonical
way in the K-theory of a certain $C^*$-algebra. The geometrical context will
determine, which $C^*$-algebra to use. A central pillar of work in the theory
of $C^*$-algebras is the Baum-Connes conjecture. Nevertheless, it has important
direct applications to the topology of manifolds, it impliese.g. the Novikov
conjecture. We will explain the Baum-Connes conjecture and put it into our
context.
  Several people contributed to these notes by reading preliminary parts and
suggesting improvements, in particular Marc Johnson, Roman Sauer, Marco Varisco
und Guido Mislin. I am very indebted to all of them. This is an elaboration of
the first chapter of the author's contribution to the proceedings of the above
mentioned "School on High Dimensional Manifold Theory" 2001 at the ICTP in
Trieste.


title:
Power requirements for cosmic ray propagation models involving diffusive
  reacceleration; estimates and implications for the damping of interstellar
  turbulence

abstract:
  We make quantitative estimates of the power supplied to the Galactic cosmic
ray population by second-order Fermi acceleration in the interstellar medium,
or as it is usually termed in cosmic ray propagation studies, diffusive
reacceleration. Using recent results on the local interstellar spectrum from
the Voyager missions we show that for parameter values, in particular the
Alfv\'en speed, typically used in propagation codes such as Galprop to fit the
B/C ratio, the power contributed by diffusive reacceleration is significant and
can be of order 50\% of the total Galactic cosmic ray power. The implications
for the damping of interstellar turbulence are briefly considered.


title:
Quantum Gravity in the Sky: Interplay between fundamental theory and
  observations

abstract:
  Observational missions have provided us with a reliable model of the
evolution of the universe starting from the last scattering surface all the way
to future infinity. Furthermore given a specific model of inflation, using
quantum field theory on curved space-times this history can be pushed
\emph{back in time} to the epoch when space-time curvature was some $10^{62}$
times that at the horizon of a solar mass black hole! However, to extend the
history further back to the Planck regime requires input from quantum gravity.
An important aspect of this input is the choice of the background quantum
geometry and of the Heisenberg state of cosmological perturbations thereon,
motivated by Planck scale physics. This paper introduces first steps in that
direction. Specifically we propose two principles that link quantum geometry
and Heisenberg uncertainties in the Planck epoch with late time physics and
explore in detail the observational consequences of the initial conditions they
select. We find that the predicted temperature-temperature (T-T) correlations
for scalar modes are indistinguishable from standard inflation at small angular
scales even though the initial conditions are now set in the deep Planck
regime. However, \emph{there is a specific power suppression at large angular
scales}. As a result, the predicted spectrum provides a better fit to the
PLANCK mission data than standard inflation, where the initial conditions are
set in the general relativity regime. Thus, our proposal brings out a deep
interplay between the ultraviolet and the infrared. Finally, the proposal also
leads to specific predictions for power suppression at large angular scales
also for the (T-E and E-E) correlations involving electric polarization. The
PLANCK team is expected to release this data in the coming year.

categories: gr-qc astro-ph.CO hep-th math-ph math.MP


title:
Existence of large-data finite-energy global weak solutions to a
  compressible Oldroyd-B model

abstract:
  A compressible Oldroyd--B type model with stress diffusion is derived from a
compressible Navier--Stokes--Fokker--Planck system arising in the kinetic
theory of dilute polymeric fluids, where polymer chains immersed in a
barotropic, compressible, isothermal, viscous Newtonian solvent, are idealized
as pairs of massless beads connected with Hookean springs. We develop a-priori
bounds for the model, including a logarithmic bound, which guarantee the
nonnegativity of the elastic extra stress tensor, and we prove the existence of
large data global-in-time finite-energy weak solutions in two space dimensions.


title:
Effect of electrical properties of glass electrodes on the performance
  of RPC detectors for the INO-ICAL experiment

abstract:
  The India-based Neutrino Observatory (INO) collaboration has chosen glass
Resistive Plate Chambers (RPCs) as the active detector elements for the Iron
Calorimeter (ICAL) experiment. In the present work, we study the electrical
properties such as bulk resistivity and relative permittivity of the glasses
from two different manufacturers and compared the performances of RPCs built
using these glasses. We conclude that the glass electrodes with larger bulk
resistivy and permittivity are better suited for manufacturing RPCs for the
ICAL experiment, as these detectors could be operated at lower bias currents
and voltages, and produce better time resolutions compared to those built with
glass electrodes of smaller bulk resistivity and permittivity.


title:
Mode-locking based on a zero-area pulse formation in a laser with a
  coherent absorber

abstract:
  We observe experimentally a mode-locking in a continuous narrow-band tunable
dye laser with molecular iodine absorber cells, which transitions have large
phase relaxation time T2. We show that the mode-locking arises due to coherent
interaction of light with the absorbing medium leading to Rabi oscillations, so
that zero-area (0{\pi}-) pulses in the absorber are formed. Such mode-locking
regime is different to most typical passive modelocking mechanisms where
saturation plays the main role.


title:
Observation of quasi-periodic solar radio bursts associated with
  propagating fast-mode waves

abstract:
  Radio emission observations from the Learmonth and Bruny Island radio
spectrographs are analysed to determine the nature of a train of discrete,
periodic radio \lq sparks\rq (finite-bandwidth, short-duration isolated radio
features) which precede a type II burst. We analyse extreme ultraviolet (EUV)
imaging from SDO/AIA at multiple wavelengths and identify a series of
quasi-periodic rapidly-propagating enhancements, which we interpret as a fast
wave train, and link these to the detected radio features. The speeds and
positions of the periodic rapidly propagating fast waves and the coronal mass
ejection (CME) were recorded using running-difference images and time-distance
analysis. From the frequency of the radio sparks the local electron density at
the emission location was estimated for each. Using an empirical model for the
scaling of density in the corona, the calculated electron density was used to
obtain the height above the surface at which the emission occurs, and the
propagation velocity of the emission location. The period of the radio sparks,
$\delta t_\mathrm{r}$=1.78$\pm$0.04 min, matches the period of the fast wave
train observed at 171 $\AA$, $\delta t_\mathrm{EUV}$=1.7 $\pm$ 0.2 min. The
inferred speed of the emission location of the radio sparks, 630 km s$^{-1}$,
is comparable to the measured speed of the CME leading edge, 500 km s$^{-1}$,
and the speeds derived from the drifting of the type II lanes. The calculated
height of the radio emission (obtained from the density) matches the observed
location of the CME leading edge. From the above evidence we propose that the
radio sparks are caused by the quasi-periodic fast waves, and the emission is
generated as they catch up and interact with the leading edge of the CME.


title: A Riemannian Network for SPD Matrix Learning

abstract:
  Symmetric Positive Definite (SPD) matrix learning methods have become popular
in many image and video processing tasks, thanks to their ability to learn
appropriate statistical representations while respecting Riemannian geometry of
underlying SPD manifolds. In this paper we build a Riemannian network
architecture to open up a new direction of SPD matrix non-linear learning in a
deep model. In particular, we devise bilinear mapping layers to transform input
SPD matrices to more desirable SPD matrices, exploit eigenvalue rectification
layers to apply a non-linear activation function to the new SPD matrices, and
design an eigenvalue logarithm layer to perform Riemannian computing on the
resulting SPD matrices for regular output layers. For training the proposed
deep network, we exploit a new backpropagation with a variant of stochastic
gradient descent on Stiefel manifolds to update the structured connection
weights and the involved SPD matrix data. We show through experiments that the
proposed SPD matrix network can be simply trained and outperform existing SPD
matrix learning and state-of-the-art methods in three typical visual
classification tasks.


title: Eye Formation in Rotating Convection

abstract:
  We consider rotating convection in a shallow, cylindrical domain. We examine
the conditions under which the resulting vortex develops an eye at its core;
that is, a region where the poloidal flow reverses and the angular momentum is
low. For simplicity, we restrict ourselves to steady, axisymmetric flows in a
Boussinesq fluid. Our numerical experiments show that, in such systems, an eye
forms as a passive response to the development of a so-called eyewall, a
conical annulus of intense, negative azimuthal vorticity that can form near the
axis and separates the eye from the primary vortex. We also observe that the
vorticity in the eyewall comes from the lower boundary layer, and relies on the
fact the poloidal flow strips negative vorticity out of the boundary layer and
carries it up into the fluid above as it turns upward near the axis. This
process is effective only if the Reynolds number is sufficiently high for the
advection of vorticity to dominate over diffusion. Finally we observe that, in
the vicinity of the eye and the eyewall, the buoyancy and Coriolis forces are
negligible, and so although these forces are crucial to driving and shaping the
primary vortex, they play no direct role in eye formation in a Boussinesq
fluid.


title:
Short note on Smithson's paper concerning Arzel\`a-Ascoli theorem for
  multifunctions

abstract:
  As indicated in the title, this paper was inspired by Smithson's work on
Arzel\`a-Ascoli theorem. Up to this point, the author's interest in the topic
has led him to generalize Arzel\`a-Ascoli theorem in the context of uniform
spaces. This approach was primarily influenced by J.L. Kelley's \textit{General
topology}. Soon after, the author learnt that in 1971, R.E. Smithson carried
over Kelley's approach to the case of point-compact multifunctions (rather than
single-valued functions). Similarly, in this paper the author would like to
carry over the result, presented in his previous paper \textit{Arzel\`a-Ascoli
theorem in uniform spaces}, to the case of point-compact multifunctions.


title:
Generative and Discriminative Voxel Modeling with Convolutional Neural
  Networks

abstract:
  When working with three-dimensional data, choice of representation is key. We
explore voxel-based models, and present evidence for the viability of
voxellated representations in applications including shape modeling and object
classification. Our key contributions are methods for training voxel-based
variational autoencoders, a user interface for exploring the latent space
learned by the autoencoder, and a deep convolutional neural network
architecture for object classification. We address challenges unique to
voxel-based representations, and empirically evaluate our models on the
ModelNet benchmark, where we demonstrate a 51.5% relative improvement in the
state of the art for object classification.


title:
Space & time discontinuities in Liouville theory and the deformed
  oscillator model

abstract:
  We consider the deformed harmonic oscillator as a discrete version of the
Liouville theory and study this model in the presence of local integrable
defects. From this, the time evolution of the defect degrees of freedom are
determined, found in the form of the local equations of motion. We also revisit
the continuous Liouville theory, deriving its local integrals of motion and
comparing these with previous results from the sine-Gordon point of
view.Finally, the generic Backlund type relations are presented, corresponding
to the implementation of time-like and space-like impurities in the continuum
model. Finally, we consider the interface of the Liouville theory with the free
massless theory. With the appropriate choice of the defect (Darboux) matrix we
are able to derive the hetero-Backlund transformation for the Liouville theory.


title:
A monolithic collapse origin for the thin/thick disc structure of ESO
  243-49

abstract:
  ESO 243-49 is a high-mass (circular velocity $v_{\rm c}\approx200\,{\rm
km\,s^{-1}}$) edge-on S0 galaxy in the Abell 2877 cluster at a distance of
$\sim95\,{\rm Mpc}$. To elucidate the origin of its thick disc, we use MUSE
science verification data to study its kinematics and stellar populations. The
thick disc emits $\sim80\%$ of the light at heights in excess of
$3.5^{\prime\prime}$ ($1.6\,{\rm kpc}$). The rotation velocities of its stars
lag by $30-40\,{\rm km\,s^{-1}}$ compared to those in the thin disc, which is
compatible with the asymmetric drift. The thick disc is found to be more
metal-poor than the thin disc, but both discs have old ages. We suggest an
internal origin for the thick disc stars in high-mass galaxies. We propose that
the thick disc formed either ${\rm a)}$ first in a turbulent phase with a high
star formation rate and that a thin disc formed shortly afterwards, or ${\rm
b)}$ because of the dynamical heating of a thin pre-existing component. Either
way, the star formation in ESO 243-49 was quenched just a few Gyrs after the
galaxy was born and the formation of a thin and a thick disc must have occurred
before the galaxy stopped forming stars. The formation of the discs was so fast
that it could be described as a monolithic collapse where several generations
of stars formed in a rapid succession.


title: Motion of Confined Particles

abstract:
  We carry out numerical evaluations of the motion of classical particles in
Minkowski Space $\mathbb{M}^{4}$ which are confined to the inside of a bag. In
particular, we analyze the structure of the paths evolving from the breaking of
the dilatation symmetry, the conformal symmetry and the combination of both
together. The confining forces arise directly from the corresponding
nonconserved currents. We demonstrate in our evaluations that these particles
under certain initial conditions move toward the interior of the bag.


title: Diffusive lossless energy and coherence transfer by noisy coupling

abstract:
  Here we show that noisy coupling can lead to diffusive lossless energy
transfer between individual quantum systems retaining a quantum character
leading to entangled stationary states. Coherence might flow diffusively while
being summarily preserved even when energy exchange is absent. Diffusive
dynamics persists even in the case when additional noise suppresses all the
unitary excitation exchange: arbitrarily strong local dephasing, while
destroying quantum correlations, is not affecting energy transfer.


title: Precession resonance in water waves

abstract:
  We describe the theory and present numerical evidence for a new type of
nonlinear resonant interaction between gravity waves on the surface of deep
water. The resonance constitutes a generalisation of the usual 'exact'
resonance as we show that exchanges of energy between the waves can be enhanced
when the interaction is three-wave rather than four and the linear frequency
mismatch, or detuning, is non-zero i.e. $\omega_1\pm\omega_2\pm\omega_3 \neq0.$
This is possible because the resonance condition is now a match between the
so-called 'precession frequency' of a given $\textit{triad interaction}$ and an
existent nonlinear frequency in the system. In the limit of weak nonlinearity
this precession frequency is simply due to the linear 'drift' of the triad
phase; therefore, it tends toward the detuning. This means precession resonance
of this type can occur at finite amplitudes, with nonlinear corrections
contributing to the resonance. We report energy transfer efficiencies of up to
40%, depending on the model options. To the authors' knowledge this represents
the first new type of nonlinear resonance in surface gravity waves since the
seminal work of Benjamin & Feir (1967).


title: Bayesian Community Detection

abstract:
  We introduce a Bayesian estimator of the underlying class structure in the
stochastic block model, when the number of classes is known. The estimator is
the posterior mode corresponding to a Dirichlet prior on the class proportions,
a generalized Bernoulli prior on the class labels, and a beta prior on the edge
probabilities. We show that this estimator is strongly consistent when the
expected degree is at least of order $\log^2{n}$, where $n$ is the number of
nodes in the network.


title:
Multiscale Sub-grid Correction Method for Time-Harmonic High-Frequency
  Elastodynamics with Wavenumber Explicit Bounds

abstract:
  The simulation of the elastodynamics equations at high-frequency suffers from
the well known pollution effect. We present a Petrov--Galerkin multiscale
sub-grid correction method that remains pollution free in natural resolution
and oversampling regimes. This is accomplished by generating corrections to
coarse-grid spaces with supports determined by oversampling lengths related to
the $\log(k)$, $k$ being the wavenumber. Key to this method are
polynomial-in-$k$ bounds for stability constants and related inf-sup constants.
To this end, we establish polynomial-in-$k$ bounds for the elastodynamics
stability constants in general Lipschitz domains with radiation boundary
conditions in $\mathbb{R}^3$. Previous methods relied on variational
techniques, Rellich identities, and geometric constraints. In the context of
elastodynamics, these suffer from the need to hypothesize a Korn's inequality
on the boundary. The methods in this work are based on boundary integral
operators and estimation of Green's function's derivatives dependence on $k$
and do not require this extra hypothesis. We also implemented numerical
examples in two and three dimensions to show the method eliminates pollution in
the natural resolution and oversampling regimes, as well as performs well when
compared to standard Lagrange finite elements.


title:
A semiparametric single-index estimator for a class of estimating
  equation models

abstract:
  We propose a two-step pseudo-maximum likelihood procedure for semiparametric
single-index regression models where the conditional variance is a known
function of the regression and an additional parameter. The Poisson
single-index regression with multiplicative unobserved heterogeneity is an
example of such models. Our procedure is based on linear exponential densities
with nuisance parameter. The pseudo-likelihood criterion we use contains a
nonparametric estimate of the index regression and therefore a rule for
choosing the smoothing parameter is needed. We propose an automatic and natural
rule based on the joint maximization of the pseudo-likelihood with respect to
the index parameter and the smoothing parameter. We derive the asymptotic
properties of the semiparametric estimator of the index parameter and the
asymptotic behavior of our `optimal' smoothing parameter. The finite sample
performances of our methodology are analyzed using simulated and real data.


title: The Bayesian Low-Rank Determinantal Point Process Mixture Model

abstract:
  Determinantal point processes (DPPs) are an elegant model for encoding
probabilities over subsets, such as shopping baskets, of a ground set, such as
an item catalog. They are useful for a number of machine learning tasks,
including product recommendation. DPPs are parametrized by a positive
semi-definite kernel matrix. Recent work has shown that using a low-rank
factorization of this kernel provides remarkable scalability improvements that
open the door to training on large-scale datasets and computing online
recommendations, both of which are infeasible with standard DPP models that use
a full-rank kernel. In this paper we present a low-rank DPP mixture model that
allows us to represent the latent structure present in observed subsets as a
mixture of a number of component low-rank DPPs, where each component DPP is
responsible for representing a portion of the observed data. The mixture model
allows us to effectively address the capacity constraints of the low-rank DPP
model. We present an efficient and scalable Markov Chain Monte Carlo (MCMC)
learning algorithm for our model that uses Gibbs sampling and stochastic
gradient Hamiltonian Monte Carlo (SGHMC). Using an evaluation on several
real-world product recommendation datasets, we show that our low-rank DPP
mixture model provides substantially better predictive performance than is
possible with a single low-rank or full-rank DPP, and significantly better
performance than several other competing recommendation methods in many cases.


title:
On the "movement" of the zeros of eigenfunctions of the Sturm-Liouville
  problem

abstract:
  We study the dependence of the zeros of eigenfunctions of Sturm-Liouville
problem on the parameters that define the boundary conditions. As a corollary,
we obtain Sturm oscillation theorem, which states that the $n$-th eigenfunction
has $n$ zeros.


title: Note on the speed of GW150914 in gravity's rainbow

abstract:
  Without breaking Lorentz invariance, we investigate the speed of graviton in
event GW150914 by using the modified dispersion relation from gravity's
rainbow. The proper range of the parameter in the modified dispersion relation
is determined by taking into account the gap between the speed of the graviton
and that obtained from event GW150914.


title:
Potential of mean force between like-charged nanoparticles: Many-body
  effect

abstract:
  Ion-mediated interaction is important for the properties of polyelectrolytes
such as colloids and nucleic acids. The effective pair interactions between two
polyelectrolytes have been investigated extensively, but the many-body effect
for multiple polyelectrolytes still remains elusive. In this work, the
many-body effect in potential of mean force (PMF) between like-charged
nanoparticles in various salt solutions has been comprehensively examined by
Monte Carlo simulation and the nonlinear Poisson-Boltzmann theory. Our
calculations show that, at high 1:1 salt, the PMF is weakly repulsive and
appears additive, while at low 1:1 salt, the additive assumption overestimates
the repulsive many-body PMF. At low 2:2 salt, the pair PMF appears weakly
repulsive while the many-body PMF can become attractive. In contrast, at high
2:2 salt, the pair PMF is apparently attractive while the many-body effect can
cause a weaker attractive PMF than that from the additive assumption. Our
microscopic analyses suggest that the elusive many-body effect is attributed to
ion-binding which is sensitive to ion concentration, ion valence, number of
nanoparticles and charges on nanoparticles.

categories: cond-mat.soft cond-mat.stat-mech physics.bio-ph physics.chem-ph


title: Calibration of the Cherenkov Telescope Array using Cosmic Ray Electrons

abstract:
  Cosmic ray electrons represent a background for gamma-ray observations with
Cherenkov telescopes, initiating air-showers which are difficult to distinguish
from photon-initiated showers. This similarity, however, and the presence of
cosmic ray electrons in every field observed, makes them potentially very
useful for calibration purposes. Here we study the precision with which the
relative energy scale and collection area/efficiency for photons can be
established using electrons for a major next generation instrument such as CTA.
We find that variations in collection efficiency on hour timescales can be
corrected to better than 1%. Furthermore, the break in the electron spectrum at
~0.9 TeV can be used to calibrate the energy scale at the 3% level on the same
timescale. For observations on the order of hours, statistical errors become
negligible below a few TeV and allow for an energy scale cross-check with
instruments such as CALET and AMS. Cosmic ray electrons therefore provide a
powerful calibration tool, either as an alternative to intensive atmospheric
monitoring and modelling efforts, or for independent verification of such
procedures.


title:
Refined large deviations asymptotics for Markov-modulated
  infinite-server systems

abstract:
  Many networking-related settings can be modeled by Markov-modulated
infinite-server systems. In such models, the customers' arrival rates and
service rates are modulated by a Markovian background process, additionally,
there are infinitely many servers (and consequently the resulting model is
often used as a proxy for the corresponding many-server model). The
Markov-modulated infinite-server model hardly allows any explicit analysis,
apart from results in terms of systems of (ordinary or partial) differential
equations for the underlying probability generating functions, and recursions
to obtain all moments. As a consequence, recent research efforts have pursued
an asymptotic analysis in various limiting regimes, notably the central-limit
regime (describing fluctuations around the average behavior) and the
large-deviations regime (focusing on rare events). Many of these results use
the property that the number of customers in the system obeys a Poisson
distribution with a random parameter.
  The objective of this paper is to develop techniques to accurately
approximate tail probabilities in the large-deviations regime. We consider the
scaling in which the arrival rates are inflated by a factor $N$, and we are
interested in the probability that the number of customers exceeds a given
level $Na$. Where earlier contributions focused on so-called $logarithmic$
$asymptotics$ of this exceedance probability (which are inherently imprecise),
the present paper improves upon those results in that $exact$ $asymptotics$ are
established. These are found in two steps: first the distribution of the random
parameter of the Poisson distribution is characterized, and then this knowledge
is used to identify the exact asymptotics. The paper is concluded by a set of
numerical experiments, in which the accuracy of the asymptotic results is
assessed.


title: Ammonia and CO Outflow around 6.7 GHz Methanol Masers

abstract:
  Single point observations are presented in NH3 (1,1) and (2,2) inversion
transitions using the Effelsberg 100 m telescope for a sample of 100 6.7 GHz
methanol masers and mapping observations in the 12CO and 13CO (1-0) transitions
using the PMO Delingha 13.7 m telescope for 82 sample sources with detected
ammonia. A further 62 sources were selected for either 12CO or 13CO line
outflow identification, producing 45 outflow candidates, 29 using 12CO and 16
using 13CO data. Twenty-two of the outflow candidates were newly identified,
and 23 had trigonometric parallax distances. Physical properties were derived
from ammonia lines and CO outflow parameters calculated. Histograms and
statistical correlations for ammonia, CO outflow parameters, and 6.7 GHz
methanol maser luminosities are also presented. No significant correlation was
found between ammonia and maser luminosity. However, weak correlations were
found between outflow properties and maser luminosities, which may indicate
that outflows are physically associated with 6.7 GHz masers.


title: Sound Attenuation in Quark Matter Due to Pairing Fluctuations

abstract:
  The sound wave in dense quark matter is subject to strong absorption due to
diquark field fluctuations above T critical. The result is another facet of
Mandelshtam-Leontovich slow relaxation time theory.


title: Ultrahigh Dimensional Variable Selection for Mapping Soil Carbon

abstract:
  Modern soil mapping is characterised by the need to interpolate samples of
geostatistical response observations and the availability of relatively large
numbers of environmental characteristics for consideration as covariates to aid
this interpolation. We demonstrate the efficiency of the Least Angle Regression
algorithm for Least Absolute Shrinkage and Selection Operator (LASSO) penalized
multiple linear regression at selecting covariates to aid the spatial
interpolation of geostatistical soil carbon observations under an ultrahigh
dimensional scenario. Where an exhaustive search of the models that could be
constructed from 800 potential covariate terms and 60 observations would be
prohibitively demanding, LASSO variable selection is accomplished with trivial
computational investment.


title:
Inverse subsemigroups of finite index in finitely generated inverse
  semigroups

abstract:
  The index of a subgroup of a group counts the number of cosets of that
subgroup. A subgroup of finite index often shares structural properties with
the group, and the existence of a subgroup of finite index with some particular
property can therefore imply useful structural information for the overgroup. A
developed theory of cosets in inverse semigroups exists, originally due to
Schein: it is defined only for closed inverse subsemigroups, and the structural
correspondences between an inverse semigroup and a closed inverse subsemigroup
of finite index are weaker than in the group case. Nevertheless, many aspects
of this theory are of interest, and some of them are addressed in this paper.
We study the basic theory of cosets in inverse semigroups, including an index
formula for chains of subgroups and an analogue of M. Hall's Theorem on
counting subgroups of finite index in finitely generated groups. We then look
in detail at the connection between the following properties of a closed
inverse submonoid of an inverse monoid: having finite index; being a
recognisable subset; being a rational subset; being finitely generated (as a
closed inverse submonoid). A remarkable result of Margolis and Meakin shows
that these properties are equivalent for closed inverse submonoids of free
inverse monoids.


title:
Simulation of Electron Beam Dynamics in a Nonmagnetized High-Current
  Vacuum Diode

abstract:
  The electron beam dynamics in a nonmagnetized high-current vacuum diode is
analyzed for different cathode-anode gap geometries. The conditions enabling to
achieve the minimal {initial} momentum spread in the electron beam are found
out. A drastic rise of current density in a vacuum diode with a ring-type
cathode is described. The effect is shown to be caused by electrostatic
repulsion.


title:
Pseudogap-induced coexistence of Fermi arcs and Fermi pockets in cuprate
  superconductors

abstract:
  One of the most intriguing puzzle is why there is a coexistence of Fermi arcs
and Fermi pockets in the pseudogap phase of cuprate superconductors? This
puzzle is calling for an explanation. Based on the t-J model in the
fermion-spin representation, the coexistence of the Fermi arcs and Fermi
pockets in cuprate superconductors is studied by taking into account the
pseudogap effect. It is shown that the pseudogap induces an energy band
splitting, and then the poles of the electron Green's function at zero energy
form two contours in momentum space, however, the electron spectral weight on
these two contours around the antinodal region is gapped out by the pseudogap,
leaving behind the low-energy electron spectral weight only located at the
disconnected segments around the nodal region. In particular, the tips of these
disconnected segments converge on the hot spots to form the closed Fermi
pockets, generating a coexistence of the Fermi arcs and Fermi pockets.
Moreover, the single-particle coherent weight is directly related to the
pseudogap, and grows linearly with doping. The calculated result of the overall
dispersion of the electron excitations is in qualitative agreement with the
experimental data. The theory also predicts that the pseudogap-induced
peak-dip-hump structure in the electron spectrum is absent from the hot-spot
directions.


title: Gossip Algorithms in Quantum Networks

abstract:
  Gossip algorithms is a common term to describe protocols for unreliable
information dissemination in natural networks, which are not optimally designed
for efficient communication between network entities. We consider application
of gossip algorithms to quantum networks and show that any quantum network can
be updated to optimal configuration with local operations and classical
communication. This allows to seed-up -- in the best case exponentially -- the
quantum information dissemination. Irrespective of the initial configuration of
the quantum network, the update requiters at most polynomial number of local
operations and classical communication.


title: High-fidelity entangling gate for double-quantum-dot spin qubits

abstract:
  Electron spins in semiconductors are promising qubits because their long
coherence times enable nearly 10^9 coherent quantum gate operations. However,
developing a scalable high-fidelity two-qubit gate remains challenging. Here,
we demonstrate an entangling gate between two double-quantum-dot spin qubits in
GaAs by using a magnetic field gradient between the two dots in each qubit to
suppress decoherence due to charge noise. When the magnetic gradient dominates
the voltage-controlled exchange interaction between electrons, qubit coherence
times increase by an order of magnitude. Using randomized benchmarking and
self-consistent quantum measurement, state, and process tomography, we measure
single-qubit gate fidelities of approximately 99% and an entangling gate
fidelity of 90%. In the future, operating double quantum dot spin qubits with
large gradients in nuclear-spin-free materials, such as Si, should enable a
two-qubit gate fidelity surpassing the threshold for fault-tolerant quantum
information processing.


title: Landau-Ginzburg skeletons

abstract:
  We study the class of indecomposable two-dimensional Landau-Ginzburg theories
with (2,2) supersymmetry and central charge c < 6 with the aim of classifying
all such theories up to marginal deformations. Our results include cases
overlooked in previous classifications. The results are rigorous for three or
fewer fields and more generally are rigorous if we assume an extra bound.
Numerics suggest that we have the complete set of indecomposable
Landau-Ginzburg families with c<6. This set consists of 38 infinite families
and a finite list of 418 sporadic cases. The basic tools are classic results of
Kreuzer and Skarke on quasi-homogeneous isolated singularities and solutions to
certain feasibility integer programming problems.


title:
Location Aware Opportunistic Bandwidth Sharing between Static and Mobile
  Users with Stochastic Learning in Cellular Networks

abstract:
  We consider location-dependent opportunistic bandwidth sharing between static
and mobile downlink users in a cellular network. Each cell has some fixed
number of static users. Mobile users enter the cell, move inside the cell for
some time and then leave the cell. In order to provide higher data rate to
mobile users, we propose to provide higher bandwidth to the mobile users at
favourable times and locations, and provide higher bandwidth to the static
users in other times. We formulate the problem as a long run average reward
Markov decision process (MDP) where the per-step reward is a linear combination
of instantaneous data volumes received by static and mobile users, and find the
optimal policy. The transition structure of this MDP is not known in general.
To alleviate this issue, we propose a learning algorithm based on single
timescale stochastic approximation. Also, noting that the unconstrained MDP can
be used to solve a constrained problem, we provide a learning algorithm based
on multi-timescale stochastic approximation. The results are extended to
address the issue of fair bandwidth sharing between the two classes of users.
Numerical results demonstrate performance improvement by our scheme, and also
the trade-off between performance gain and fairness.


title: Global solutions to random 3D vorticity equations for small initial data

abstract:
  One proves the existence and uniqueness in $(L^p(\mathbb{R}^3))^3$,
$\frac{3}{2}<p<2$, of a global mild solution to random vorticity equations
associated to stochastic $3D$ Navier-Stokes equations with linear
multiplicative Gaussian noise of convolution type, for sufficiently small
initial vorticity. This resembles some earlier deterministic results of T. Kato
[15] and are obtained by treating the equation in vorticity form and reducing
the latter to a random nonlinear parabolic equation. The solution has maximal
regularity in the spatial variables and is weakly continuous in $(L^3\cap
L^{\frac{3p}{4p-6}})^3$ with respect to the time variable. Furthermore, we
obtain the pathwise continuous dependence of solutions with respect to the
initial data.


title: Photon emission of extremal Kerr-Newman black holes

abstract:
  In this paper, we deal with the null geodesics extending from the
near-horizon region out to a distant observatory in an extremal Kerr-Newman
black hole background. In particular, using the matched asymptotic expansion
method, we analytically solve the null geodesics near the superradiant bound in
the form of algebraic equations. For the case that the photon trajectories are
limited in the equatorial plane, the shifts in the azimuthal angle and time are
obtained.


title:
Two-channel Kondo physics due to As vacancies in the layered compound
  ZrAs1.58Se0.39

abstract:
  We address the origin of the magnetic-field independent -|A| T^{1/2} term
observed in the low-temperature resistivity of several As-based metallic
systems of the PbFCl structure type. For the layered compound
ZrAs_{1.58}Se_{0.39}, we show that vacancies in the square nets of As give rise
to the low-temperature transport anomaly over a wide temperature regime of
almost two decades in temperature. This low-temperature behavior is in line
with the non-magnetic version of the two-channel Kondo effect, whose origin we
ascribe to a dynamic Jahn-Teller effect operating at the vacancy-carrying As
layer with a C_4 symmetry. The pair-breaking nature of the dynamical defects in
the square nets of As explains the low superconducting transition temperature
T_{\rm{c}}\approx 0.14 K of ZrAs_{1.58}Se_{0.39}, as compared to the
free-of-vacancies homologue ZrP_{1.54}S_{0.46} (T_{\rm{c}}\approx 3.7 K). Our
findings should be relevant to a wide class of metals with disordered pnictogen
layers.


title:
Band Gap Engineering with Ultralarge Biaxial Strains in Suspended
  Monolayer MoS2

abstract:
  We demonstrate the continuous and reversible tuning of the optical band gap
of suspended monolayer MoS2 membranes by as much as 500 meV by applying very
large biaxial strains. By using chemical vapor deposition (CVD) to grow
crystals that are highly impermeable to gas, we are able to apply a pressure
difference across suspended membranes to induce biaxial strains. We observe the
effect of strain on the energy and intensity of the peaks in the
photoluminescence (PL) spectrum, and find a linear tuning rate of the optical
band gap of 99 meV/%. This method is then used to study the PL spectra of
bilayer and trilayer devices under strain, and to find the shift rates and
Gr\"uneisen parameters of two Raman modes in monolayer MoS2. Finally, we use
this result to show that we can apply biaxial strains as large as 5.6% across
micron sized areas, and report evidence for the strain tuning of higher level
optical transitions.


title: The Derived Category of Sheaves of Commutative DG Rings (Preview)

abstract:
  In this short paper we outline (mostly without proofs) our new approach to
the derived category of sheaves of commutative DG rings. The proofs will appear
in a subsequent paper.
  Among other things, we explain how to form the derived intersection of two
closed subschemes inside a given algebraic scheme X, without recourse to
simplicial or higher homotopical methods, and without any global assumptions on
X.


title: Separation of Dynamic and Nondynamic Correlation

abstract:
  The account of electron correlation and its efficient separation into dynamic
and nondynamic parts plays a key role in the development of computational
methods. In this paper we suggest a physically-sound matrix formulation to
split electron correlation into dynamic and nondynamic parts using the
two-particle cumulant matrix and a measure of the deviation from idempotency of
the first-order density matrix. These matrices are applied to a two-electron
model, giving rise to a simplified electron correlation index that ($i$)
depends only on natural orbitals and their occupancies, ($ii$) can be
straightforwardly decomposed into orbital contributions and ($iii$) splits into
dynamic and nondynamic correlation parts that ($iv$) admit a local version.
These expressions are shown to account for dynamic and nondynamic correlation
in a variety of systems containing different electron correlation regimes, thus
providing the first separation of dynamic and nondynamic correlation using
solely natural orbital occupancies.


title:
Detecting Dominant Vanishing Points in Natural Scenes with Application
  to Composition-Sensitive Image Retrieval

abstract:
  Linear perspective is widely used in landscape photography to create the
impression of depth on a 2D photo. Automated understanding of linear
perspective in landscape photography has several real-world applications,
including aesthetics assessment, image retrieval, and on-site feedback for
photo composition, yet adequate automated understanding has been elusive. We
address this problem by detecting the dominant vanishing point and the
associated line structures in a photo. However, natural landscape scenes pose
great technical challenges because often the inadequate number of strong edges
converging to the dominant vanishing point is inadequate. To overcome this
difficulty, we propose a novel vanishing point detection method that exploits
global structures in the scene via contour detection. We show that our method
significantly outperforms state-of-the-art methods on a public ground truth
landscape image dataset that we have created. Based on the detection results,
we further demonstrate how our approach to linear perspective understanding
provides on-site guidance to amateur photographers on their work through a
novel viewpoint-specific image retrieval system.


title:
Impact of lattice dynamics on the phase stability of metamagnetic FeRh:
  Bulk and thin films

abstract:
  We present phonon dispersions, element-resolved vibrational density of states
(VDOS) and corresponding thermodynamic properties obtained by a combination of
density functional theory (DFT) and nuclear resonant inelastic X-ray scattering
(NRIXS) across the metamagnetic transition of B2 FeRh in the bulk material and
thin epitaxial films. We see distinct differences in the VDOS of the
antiferromagnetic (AF) and ferromagnetic (FM) phase which provide a microscopic
proof of strong spin-phonon coupling in FeRh. The FM VDOS exhibits a particular
sensitivity to the slight tetragonal distortions present in epitaxial films,
which is not encountered in the AF phase. This results in a notable change in
lattice entropy, which is important for the comparison between thin film and
bulk results. Our calculations confirm the recently reported lattice
instability in the AF phase. The imaginary frequencies at the $X$-point depend
critically on the Fe magnetic moment and atomic volume. Analyzing these non
vibrational modes leads to the discovery of a stable monoclinic ground state
structure which is robustly predicted from DFT but not verified in our thin
film experiments. Specific heat, entropy and free energy calculated within the
quasiharmonic approximation suggest that the new phase is possibly suppressed
because of its relatively smaller lattice entropy. In the bulk phase, lattice
degrees of freedom contribute with the same sign and in similar magnitude to
the isostructural AF-FM phase transition as the electronic and magnetic
subsystems and therefore needs to be included in thermodynamic modeling.


title:
Surface Reactivity Enhancement by O2 Dissociation on a Single-layer MgO
  Film Deposited on Metal Substrate

abstract:
  Improving reactivity on an insulating surface is crucial due to their
important applications in surface catalytic reactions. In this work, we carried
out first-principles calculations to investigate the adsorption of O2 on a
single-layer MgO(100) film deposited on metal substrate. The adsorption
configurations, reaction pathways, molecular dynamics simulations, and
electronic properties are reported. We reveal that O2 can completely dissociate
on the surface, which is in sharp contrast to that on MgO(100) films thicker
than one monolayer. The dissociated O2 tends to penetrate into the interfacial
region, behaving like a switch to trigger subsequent chemical reactions. As an
example, the interplay between water and the interfacial oxygen results in the
formation of hydroxyl radicals. This study paves an avenue to accomplish the
desired surface catalytic reactions, especially those involving oxygen.


title:
Problems of unique determination of domains by the relative metrics on
  their boundaries

abstract:
  This survey is devoted to discussing the problems of the unique determination
of surfaces that are the boundaries of (generally speaking) nonconvex domains.
  First (in Sec. 2) we examine some results on the problem of the unique
determination of domains by the relative metrics of the boundaries. Then, in
Sec. 3, we study rigidity conditions for the boundaries of submanifolds in a
Riemannian manifold. The final part (Sec. 4) is concerned with the unique
determination of domains by the condition of the local isometry of boundaries
in the relative metrics.
  The survey in particular contains the results of arXiv:1401.7295,
arXiv:1305.6169, arXiv:1511.04235.


title:
Nonuniform probability modulation for reducing energy consumption of
  remote sensors

abstract:
  One of the main goals of 5G wireless telecommunication technology is
improving energy efficiency, especially of remote sensors which should be able
for example to transmit on average 1bit/s for 10 years from a single AAA
battery. There will be discussed using modulation with nonuniform probability
distribution of symbols for improving energy efficiency of transmission at cost
of reduced throughput. While the zero-signal (silence) has zero energy cost to
emit, it can carry information if used alongside other symbols. If used more
frequently than others, for example for majority of time slots or OFDM
subcarriers, the number of bits transmitted per energy unit can be
significantly increased. For example for hexagonal modulation and zero noise,
this amount of bits per energy unit can be doubled by reducing throughput 2.7
times, thanks to using the zero-signal with probability $\approx$ 0.84. There
will be discussed models and methods for such nonuniform probability
modulations (NPM).


title: Quantum Capacitance of a Topological Insulator-Ferromagnet Interface

abstract:
  We study the quantum capacitance in a topological insulator thin film system
magnetized in the in-plane direction in the presence of an out-of-plane
magnetic field and hexagonal warping. To first order, the modification in
quantum capacitance due to hexagonal warping compared to the clean case, where
both the in-plane magnetization and hexagonal warping are absent, is always
negative, and increases in magnitude monotonically with the energy difference
from the charge neutrality point. In contrast, the change in the quantum
capacitance due to in-plane magnetization oscillates with the energy in
general, except when a certain relation between the inter-surface coupling, out
of plane Zeeman energy splitting and magnetic field strength is satisfied. In
this special case, the quantum capacitance remains unchanged by the in-plane
magnetization for all energies.


title: Generalized Assignment Problem: Truthful Mechanism Design without Money

abstract:
  In this paper, we study a problem of truthful mechanism design for a
strategic variant of the generalized assignment problem (GAP) in a both
payment-free and prior-free environment. In GAP, a set of items has to be
optimally assigned to a set of bins without exceeding the capacity of any
singular bin. In the strategic variant of the problem we study, bins are held
by strategic agents, and each agent may hide its compatibility with some items
in order to obtain items of higher values. The compatibility between an agent
and an item encodes the willingness of the agent to receive the item. Our goal
is to maximize total value (sum of agents' values, or social welfare) while
certifying no agent can benefit from hiding its compatibility with items. The
model has applications in auctions with budgeted bidders. For two variants of
the problem, namely \emph{multiple knapsack problem} in which each item has the
same size and value over bins, and \emph{density-invariant GAP} in which each
item has the same value density over the bins, we propose truthful
$4$-approximation algorithms. For the general problem, we propose an
$O(\ln{(U/L)})$-approximation mechanism where $U$ and $L$ are the upper and
lower bounds for value densities of the compatible item-bin pairs.


title: Visual place recognition using landmark distribution descriptors

abstract:
  Recent work by Suenderhauf et al. [1] demonstrated improved visual place
recognition using proposal regions coupled with features from convolutional
neural networks (CNN) to match landmarks between views. In this work we extend
the approach by introducing descriptors built from landmark features which also
encode the spatial distribution of the landmarks within a view. Matching
descriptors then enforces consistency of the relative positions of landmarks
between views. This has a significant impact on performance. For example, in
experiments on 10 image-pair datasets, each consisting of 200 urban locations
with significant differences in viewing positions and conditions, we recorded
average precision of around 70% (at 100% recall), compared with 58% obtained
using whole image CNN features and 50% for the method in [1].


title:
Asymptotic Reissner-Nordstr\"om solution within nonlinear
  electrodynamics

abstract:
  A model of nonlinear electrodynamics coupled with the gravitational field is
studied. We obtain the asymptotic black hole solutions at $r\rightarrow 0$ and
$r\rightarrow \infty$. The asymptotic at $r\rightarrow 0$ is shown, and we find
corrections to the Reissner-Nordstr\"om solution and Coulomb's law at
$r\rightarrow\infty$. The mass of the black hole is evaluated having the
electromagnetic origin. We investigate the thermodynamics of charged black
holes and their thermal stability. The critical point corresponding to the
second-order phase transition (where heat capacity diverges) is found. If the
mass of the black hole is greater than the critical mass, the black hole
becomes unstable.


title:
Evaluation of a New Vasculature by High Resolution Light Microscopy:
  Primo Vessel and Node

abstract:
  The primo vascular system is composed of nodes and vessels. The bundle of
sub-vessels of the promo vessel is laid into an external jacket composed of
endothelial cells. The node is heterogeneous in nature, composed of twisted
sub-vessel bundles that fill up nearly the entire node volume. The enlarged
sub-vessel inside the node harbors microcells that express stem cells and stem
cells niche markers. We conclude that these microcells are progenitors of
multipotent stem cells and the nodes serve as the stem cell niches outside the
bone marrow.


title:
Role of ($\alpha$,n) reactions under $r$-process conditions in
  neutrino-driven winds revisited

abstract:
  Background: The astrophysical $r$-process occurs in an explosive
astrophysical event under extremely neutron-rich conditions, leading to
(n,$\gamma$)-($\gamma$,n) equilibrium along isotopic chains which peaks around
neutron separation energies of a few MeV. Nuclei with larger $Z$ are usually
produced by $\beta^-$-decay, but under certain conditions also $\alpha$-induced
reactions may become relevant for the production of nuclei with $Z+2$.
  Purpose: The uncertainties of the reaction rates of these $\alpha$-induced
reactions are discussed within the statistical model. As an example,
$\alpha$-induced ($\alpha$,n) and $(\alpha$,$x$n) reaction cross sections for
the neutron-rich $^{86}$Se nucleus are studied in detail.
  Method: In a first step, the relevance of ($\alpha$,n) and $(\alpha$,$x$n)
reactions is analyzed. Next the uncertainties are determined from a variation
of the $\alpha$-nucleus potential which is the all-dominant parameter for the
astrophysical $Z \rightarrow Z+2$ reaction rate.
  Results: It is found that the $r$-process flow towards nuclei with larger $Z$
is essentially influenced only by the $\alpha$-nucleus potential whereas the
other ingredients of the statistical model play a very minor role. This finding
is based on the fact that the flow towards larger $Z$ depends on the sum over
all ($\alpha$,$x$n) cross sections which is practically identical to the total
$\alpha$-induced reaction cross section.
  Conclusions: $\alpha$-nucleus potentials play an important role under certain
$r$-process conditions because the flow towards larger $Z$ depends sensitively
on the total $\alpha$-induced reaction cross section. The uncertainty of the
reaction rate is about a factor of two to three at higher temperatures and
exceeds one order of magnitude at very low temperatures.


title:
Vibrational effects in charge transport through a molecular double
  quantum dot

abstract:
  Recent progress in the field of molecular electronics has revealed the
fundamental importance of the coupling between the electronic degrees of
freedom and specific vibrational modes. Considering the examples of a molecular
dimer and a carbon nanotube double quantum dot, we here theoretically
investigate transport through a two-site system that is strongly coupled to a
single vibrational mode. Using a quantum master equation approach, we
demonstrate that, depending on the relative positions of the two dots,
electron-phonon interactions can lead to negative differential conductance and
suppression of the current through the system. We also discuss the experimental
relevance of the presented results and possible implementations of the studied
system.


title:
On Reay's relaxed Tverberg conjecture and generalizations of Conway's
  thrackle conjecture

abstract:
  Reay's relaxed Tverberg conjecture and Conway's thrackle conjecture are open
problems about the geometry of pairwise intersections. Reay asked for the
minimum number of points in Euclidean d-space that guarantees any such point
set admits a partition into r parts, any k of whose convex hulls intersect.
Here we give new and improved lower bounds for this number, which Reay
conjectured to be independent of k. We prove a colored version of Reay's
conjecture for k sufficiently large, but nevertheless k independent of
dimension d. Requiring convex hulls to intersect pairwise severely restricts
combinatorics. This is a higher-dimensional analog of Conway's thrackle
conjecture or its linear special case. We thus study convex-geometric and
higher-dimensional analogs of the thrackle conjecture alongside Reay's problem
and conjecture (and prove in two special cases) that the number of convex sets
in the plane is bounded by the total number of vertices they involve whenever
there exists a transversal set for their pairwise intersections. We thus
isolate a geometric property that leads to bounds as in the thrackle
conjecture. We also establish tight bounds for the number of facets of
higher-dimensional analogs of linear thrackles and conjecture their continuous
generalizations.


title: AGN Outflow Shocks on Bonnor-Ebert Spheres

abstract:
  Feedback from Active Galactic Nuclei (AGN) and subsequent jet cocoons and
outflow bubbles can have a significant impact on star formation in the host
galaxy. To investigate feedback physics on small scales, we perform
hydrodynamic simulations of realistically fast AGN winds striking Bonnor-Ebert
(BE) spheres and examine gravitational collapse and ablation. We test AGN wind
velocities ranging from 300--3,000 km s$^{-1}$ and wind densities ranging from
0.5--10 $m_\mathrm{p}\,\mathrm{cm}^{-3}$. We include heating and cooling of
low- and high-temperature gas, self-gravity, and spatially correlated
perturbations in the shock, with a maximum resolution of 0.01 pc. We find that
the ram pressure is the most important factor that determines the fate of the
cloud. High ram pressure winds increase fragmentation and decrease the star
formation rate, but also cause star formation to occur on a much shorter time
scale and with increased velocities of the newly formed stars. We find a
threshold ram pressure of $\sim 2\times10^{-8}$ dyne cm$^{-2}$ above which
stars are not formed because the resulting clumps have internal velocities
large enough to prevent collapse. Our results indicate that simultaneous
positive and negative feedback will be possible in a single galaxy as AGN wind
parameters will vary with location within a galaxy.


title:
Meta-instrument: high speed positioning and tracking platform for
  near-field optical imaging microscopes

abstract:
  High resolution and high throughput imaging are typically mutually exclusive.
The meta-instrument pairs high resolution optical concepts such as
nano-antennas, superoscillatory lenses and hyperlenses with a miniaturized
opto-mechatronic platform for precise and high speed positioning of the optical
elements at lens-to-sample separations that are measured in tens of nanometers.
Such platform is a necessary development for bringing near-field optical
imaging techniques to their industrial application. Towards this purpose, we
present two designs and proof-of-principle instruments that are aimed at
realizing sub-nanometer positional precision with a 100 kHz bandwidth.


title:
Fundamental Results for Pseudo-Differential Operators of Type
  $\mathbf{1},\mathbf{1}$

abstract:
  This paper develops some deeper consequences of an extended definition,
proposed previously by the author, of pseudo-differential operators that are of
type $1,1$ in H\"ormander's sense. Thus, it contributes to the long-standing
problem of creating a systematic theory of such operators. It is shown that
type $1,1$-operators are defined and continuous on the full space of temperate
distributions, if they fulfil H\"ormander's twisted diagonal condition, or more
generally if they belong to the self-adjoint subclass; and that they are always
defined on the temperate smooth functions. As a main tool the paradifferential
decomposition is derived for type $1,1$-operators, and to confirm a natural
hypothesis the symmetric term is shown to cause the domain restrictions;
whereas the other terms are shown to define nice type $1,1$-operators
fulfilling the twisted diagonal condition. The decomposition is analysed in the
type $1,1$-context by combining the Spectral Support Rule and the factorisation
inequality, which gives pointwise estimates of pseudo-differential operators in
terms of maximal functions.


title: Graph partitions and cluster synchronization in networks of oscillators

abstract:
  Synchronization over networks depends strongly on the structure of the
coupling between the oscillators. When the coupling presents certain
regularities, the dynamics can be coarse-grained into clusters by means of
External Equitable Partitions of the network graph and their associated
quotient graphs. We exploit this graph-theoretical concept to study the
phenomenon of cluster synchronization, in which different groups of nodes
converge to distinct behaviors. We derive conditions and properties of networks
in which such clustered behavior emerges, and show that the ensuing dynamics is
the result of the localization of the eigenvectors of the associated graph
Laplacians linked to the existence of invariant subspaces. The framework is
applied to both linear and non-linear models, first for the standard case of
networks with positive edges, before being generalized to the case of signed
networks with both positive and negative interactions. We illustrate our
results with examples of both signed and unsigned graphs for consensus dynamics
and for partial synchronization of oscillator networks under the master
stability function as well as Kuramoto oscillators.


title: Finite Temperature QCD Sum Rules: a Review

abstract:
  The method of QCD sum rules at finite temperature is reviewed, with emphasis
on recent results. These include predictions for the survival of charmonium and
bottonium states, at and beyond the critical temperature for de-confinement, as
later confirmed by lattice QCD simulations. Also included are determinations in
the light-quark vector and axial-vector channels, allowing to analyse the
Weinberg sum rules, and predict the dimuon spectrum in heavy ion collisions in
the region of the rho-meson. Also in this sector, the determination of the
temperature behaviour of the up-down quark mass, together with the pion decay
constant, will be described. Finally, an extension of the QCD sum rule method
to incorporate finite baryon chemical potential is reviewed.


title: Coherent pion production in proton-deuteron collisions

abstract:
  Values of the proton analysing power in the
$pd\to{}^{3}\textrm{He}\,\pi^0/^{3}\textrm{H}\,\pi^+$ reactions at 350-360~MeV
per nucleon were obtained by using a polarised proton beam incident on a
deuterium cluster-jet target and with a polarised deuteron beam incident on a
target cell filled with polarised hydrogen. These results have a much larger
angular coverage than existing data. First measurements are also presented of
the deuteron vector analysing power and the deuteron-proton spin correlations.
Data were also obtained on the deuteron-proton spin correlation and proton
analysing power at small angles at 600~MeV per nucleon, though the angular
coverage at this energy was much more restricted even when using a deuteron
beam. By combining the extrapolated values of the spin correlations to the
forward or backward directions with published measurements of the deuteron
tensor analysing powers, the relative phases between the two non-vanishing
amplitudes were evaluated.


title:
Thick, syndetic, and piecewise syndetic subsets of Fra\"iss\'e
  structures

abstract:
  We define and undertake a systematic study of thick, syndetic, and piecewise
syndetic subsets of a Fra\"iss\'e structure. Each of these collections forms a
family in the sense of Akin and Glasner [AG], and we define and study
ultrafilters on each of these families, paying special attention to
ultrafilters on the thick sets. In the process, we generalize many results of
Bergelson, Hindman, and McCutcheon [BHM]. We also discuss some abstract
questions about families implicit in the work of Akin and Glasner.


title:
Splitting Nodes and Linking Channels: A Method for Assembling
  Biocircuits from Stochastic Elementary Units

abstract:
  Akin to electric circuits, we construct biocircuits that are manipulated by
cutting and assembling channels through which stochastic information flows.
This diagrammatic manipulation allows us to create a method which constructs
networks by joining building blocks selected so that (a) they cover only basic
processes; (b) it is scalable to large networks; (c) the mean and
variance-covariance from the Pauli master equation form a closed system and;
(d) given the initial probability distribution, no special boundary conditions
are necessary to solve the master equation. The method aims to help with both
designing new synthetic signalling pathways and quantifying naturally existing
regulatory networks.


title: Electrons, holes, and spin in the IV-VI monolayer 'four-six-enes'

abstract:
  Bandedge states in the indirect-gap group-IV metal monochalcogenide
monolayers ('four-six-enes' such as SnS, GeTe, etc.) inherit the properties of
nearby reciprocal space points of high symmetry at the Brillouin zone edge. We
employ group theory and the method of invariants to capture these essential
symmetries in effective Hamiltonians including spin-orbit coupling, and use
perturbation theory to shed light on the nature of the bandedge states. In
particular, we show how the structure of derived wavefunctions leads to
specific dominant momentum and spin scattering mechanisms for both valence
holes and conduction electrons, we analyze the direct optical transitions
across the bandgap, and expose the interactions responsible for subtle features
of the local dispersion relations.


title:
Effect of a sausage oscillation on radio zebra-pattern structures in a
  solar flare

abstract:
  Sausage modes that are axisymmetric fast magnetoacoustic oscillations of
solar coronal loops are characterized by variation of the plasma density and
magnetic field, and hence cause time variations of the electron plasma
frequency and cyclotron frequency. The latter parameters determine the
condition for the double plasma resonance (DPR), which is responsible for the
appearance of zebra-pattern (ZP) structures in time spectra of solar type IV
radio bursts. We perform numerical simulations of standing and propagating
sausage oscillations in a coronal loop modeled as a straight, field-aligned
plasma slab, and determine the time variation of the DPR layer locations.
Instant values of the plasma density and magnetic field at the DPR layers
allowed us to construct skeletons of the time variation of ZP stripes in radio
spectra. In the presence of a sausage oscillation, the ZP structures are shown
to have characteristic wiggles with the time period prescribed by the sausage
oscillation. Standing and propagating sausage oscillations are found to have
different signatures in ZP patterns. We conclude that ZP wiggles can be used
for the detection of short-period sausage oscillations and the exploitation of
their seismological potential.


title:
Robust Volume Minimization-Based Matrix Factorization for Remote Sensing
  and Document Clustering

abstract:
  This paper considers \emph{volume minimization} (VolMin)-based structured
matrix factorization (SMF). VolMin is a factorization criterion that decomposes
a given data matrix into a basis matrix times a structured coefficient matrix
via finding the minimum-volume simplex that encloses all the columns of the
data matrix. Recent work showed that VolMin guarantees the identifiability of
the factor matrices under mild conditions that are realistic in a wide variety
of applications. This paper focuses on both theoretical and practical aspects
of VolMin. On the theory side, exact equivalence of two independently developed
sufficient conditions for VolMin identifiability is proven here, thereby
providing a more comprehensive understanding of this aspect of VolMin. On the
algorithm side, computational complexity and sensitivity to outliers are two
key challenges associated with real-world applications of VolMin. These are
addressed here via a new VolMin algorithm that handles volume regularization in
a computationally simple way, and automatically detects and {iteratively
downweights} outliers, simultaneously. Simulations and real-data experiments
using a remotely sensed hyperspectral image and the Reuters document corpus are
employed to showcase the effectiveness of the proposed algorithm.


title: Black Holes Evaporate Non-Thermally

abstract:
  It is shown that the Hawking radiation and staying at the Schwarzschild state
are not consistent for black holes as graviton balls. The only exception is the
eternal black hole.


title: Spectral investigation of the noise influencing multi-qubit states

abstract:
  Characterizing and understanding noise affecting quantum states has immense
benefits in spectroscopy as well as in realizing quantum devices. Transverse
relaxation times under a set of dynamical decoupling (DD) sequences with
varying interpulse delays were earlier used for obtaining the noise spectral
densities of single-qubit coherences. In this work, using a pair of homonuclear
spins and NMR techniques, we experimentally characterize noise in certain
decoherence-free subspaces. We also explore the noise of similar states in a
heteronuclear spin pair. Further, using a 10-qubit system, we investigate noise
profiles of various multiqubit coherences and study the scaling of noise with
respect to the coherence order. Finally, using the experimentally obtained
noise spectrum of the 10-qubit NOON state, we predict the performance of a
Uhrig DD sequence and verify it experimentally.


title:
Wave turbulence theory for gravitational waves in general relativity:
  The Space-Time Kolmogorov spectrum

abstract:
  The recent observation of gravitational waves, stimulates the question of the
longtime evolution of the space-time fluctuations. Gravitational waves interact
themselves through the nonlinear character of Einstein's equations of general
relativity. This nonlinear wave interaction allows the spectral energy transfer
from mode to mode. According to the wave turbulence theory, the weakly
nonlinear interaction of gravitational waves leads to the existence of an
irreversible kinetic regime that dominates the longtime evolution. The
resulting kinetic equation suggests the existence of an equilibrium wave
spectrum and the existence of a non-equilibrium Kolmogorov-Zakharov spectrum
for spatio-temporal fluctuations. Evidence of these solutions extracted in the
fluctuating signal of the recent observations will be discussed in the paper.
Probably, the present results would be pertinent in the new age of development
of gravitational astronomy, as well as, in new tests of General Relativity.


title: DICE2013R-mc: A Matlab / CasADi Implementation of Vanilla DICE 2013R

abstract:
  This brief document provides a description of how to use DICE2013R-mc
\cite{DICE2013R-mc}, a Matlab and CasADi-based implementation of the Dynamic
Integrated model of Climate and Economy (DICE). DICE2013R-mc provides the same
basic functionality as the GAMS code (A manual is available for DICE2013R
DICEManual). However, the description of the model in the manual (DICEManual)
differs in several respects from the available code (DICECode). As our aim is
replicate the functionality of (DICECode}, the description of the model is in
reference to the implementation in (DICECode) rather than the description in
(DICEManual). for DICE2013R as available at (DICECode).


title: Robust benchmarking in noisy environments

abstract:
  We propose a benchmarking strategy that is robust in the presence of timer
error, OS jitter and other environmental fluctuations, and is insensitive to
the highly nonideal statistics produced by timing measurements. We construct a
model that explains how these strongly nonideal statistics can arise from
environmental fluctuations, and also justifies our proposed strategy. We
implement this strategy in the BenchmarkTools Julia package, where it is used
in production continuous integration (CI) pipelines for developing the Julia
language and its ecosystem.


title:
Possibility of the use of Cartesian method in the proofs of fundamental
  theorems of school planimetry

abstract:
  We show how Cartesian method can be used in the proof of fundamental
planimetric topics of the school course, such as introduction of trigonometric
functions, equation of a line and similarity of triangles.
  This work also can be considered as a plan of the school course of geometry,
where the Cartesian method plays the main role.


title:
A new direction for dark matter research: intermediate mass compact halo
  objects

abstract:
  The failure to find evidence for elementary particles that could serve as the
constituents of dark matter brings to mind suggestions that dark matter might
consist of massive compact objects (MACHOs). In particular, it has recently
been argued that MACHOs with masses > 15 solar masses may have been
prolifically produced at the onset of the big bang. Although a variety of
astrophysical signatures for primordial MACHOs with masses in this range have
been discussed in the literature, we favor a strategy that uses the potential
for gravitational microlensing of stars outside our galaxy to directly detect
the presence of MACHOs in the halo of our galaxy. We point out that the effect
of the motion of the Earth on the shape of the microlensing brightening curves
provides a promising approach to confirming over the course of next several
years that dark matter consists of MACHOs.


title: Merging Galaxies with Tidal Tails in COSMOS to z=1

abstract:
  Tidal tails are created in major mergers involving disk galaxies. How the
tidal tails trace the assembly history of massive galaxies remains to be
explored. We identify a sample of 461 merging galaxies with long tidal tails
from 35076 galaxies mass-complete at $M_\star\ge 10^{9.5}\,M_{\odot}$ and
$0.2\leq z\leq1$ based on HST/ACS F814W imaging data and public catalogs of the
COSMOS field. The long tails refer to these with length equal to or longer than
the diameter of their host galaxies. The mergers with tidal tails are selected
using our novel $A_{\rm O}-D_{\rm O}$ technique for strong asymmetric features
together with visual examination. Our results show that the fraction of
tidal-tailed mergers evolves mildly with redshift, as $\sim (1+z)^{2.0\pm0.4}$,
and becomes relatively higher in less massive galaxies out to $z=1$. With a
timescale of 0.5 Gyr for the tidal-tailed mergers, we obtain that the
occurrence rate of such mergers follows $0.01\pm 0.007\,(1+z)^{2.3\pm 1.4}$
Gyr$^{-1}$ and corresponds to $\sim0.3$ events since $z=1$ and roughly
one-third of the total budget of major mergers from the literature. For
disk-involved major mergers, nearly half of them have undergone a phase with
long tidal tails


title: Ptolemy Constants as Described by Eccentricity

abstract:
  Let J denote a simple closed curve in the plane. Let points a, b, c, d \in J
occur in this order when traversing J in a counterclockwise direction. Define
p(a,b,c,d) to be the ratio of ab*cd+ad*bc to ac*bd, where zw denotes distance
between z and w. Define P(J) to be the supremum of p over all such points.
Harmaala & Kl\'en [1] provided bounds on P(J) when J is an ellipse or rectangle
of eccentricity \epsilon. We nonrigorously give formulas for P(J) here, in the
hope that someone else can fill gaps in our reasoning.


title:
Surrogacy of progression free survival for overall survival in
  metastatic breast cancer studies: meta-analyses of published studies

abstract:
  Purpose: PFS is often used as a surrogate endpoint for OS in metastatic
breast cancer studies. We have evaluated the association of treatment effect on
PFS with significant HR$_{OS}$ (and how this association is affected by other
factors) in published prospective metastatic breast cancer studies.
  Methods: A systematic literature search in PubMed identified prospective
metastatic breast cancer studies. Treatments effects on PFS were determined
using hazard ratio (HR$_{PFS}$), increase in median PFS ($\Delta$MED$_{PFS}$)
and % increase in median PFS (%$\Delta$MED$_{PFS}$). Diagnostic accuracy of PFS
measures (HR$_{PFS}$, $\Delta$MED$_{PFS}$ and %$\Delta$MED$_{PFS}$) in
predicting significant HR$_{OS}$ was assessed using receiver operating
characteristics (ROC) curves and classification trees approach.
  Results: Seventy-three cases (i.e., treatment to control comparisons) from 64
individual publications were identified for the analyses. Of these, 16 cases
reported significant treatment effect on HR$_{OS}$ at 5% level of significance.
Median number of deaths reported in these cases were 156. Area under the ROC
curve (AUC) for diagnostic measures as HR$_{PFS}$, $\Delta$MED$_{PFS}$ and
%$\Delta$MED$_{PFS}$ were 0.69, 0.70 and 0.75, respectively. Classification
tree results identified %$\Delta$MED$_{PFS}$ and number of deaths as diagnostic
measure for significant HR$_{OS}$. Only 7.9\% (3/39) cases with
$\Delta$MED$_{PFS}$ shorter than 48.27\% reported significant HR$_{OS}$. There
were 7 cases with $\Delta$MED$_{PFS}$ of 48.27\% or more and number of deaths
reported as 227 or more -- of these 5 cases reported significant HR$_{OS}$.
  Conclusion: %$\Delta$MED$_{PFS}$ was found as better diagnostic measure for
significant HR$_{OS}$. Our analysis results also suggest that consideration of
total number of deaths may further improve its diagnostic performance.


title: Validity and Entailment in Modal and Propositional Dependence Logics

abstract:
  The computational properties of modal and propositional dependence logics
have been extensively studied over the past few years, starting from a result
by Sevenster showing NEXPTIME-completeness of the satisfiability problem for
modal dependence logic. Thus far, however, the validity and entailment
properties of these logics have remained mostly unaddressed. This paper
provides a comprehensive classification of the complexity of validity and
entailment in various modal and propositional dependence logics. The logics
examined are obtained by extending the standard modal and propositional logics
with notions of dependence, independence, and inclusion in the team semantics
context. In particular, we address the question of the complexity of validity
in modal dependence logic. By showing that it is NEXPTIME-complete we refute an
earlier conjecture proposing a higher complexity for the problem.


title: Baryon number fluctuations at finite temperature and density

abstract:
  We investigate baryon number fluctuations for finite temperature and density
in two-flavor QCD. This is done within a QCD-improved low-energy effective
theory in an extension of the approach put forward in [1,2]. In the present
work we aim at improving the predictive power of this approach for large
temperatures and density, that is, for small collision energies. This is
achieved by taking into account the full frequency dependence of the quark
dispersion. This ensures the necessary Silver Blaze property of finite density
QCD for the first time, which so far was only implemented approximately.
Moreover, we show that Polyakov loop fluctuations have a sizeable impact at
large temperatures and density. The results for the kurtosis of baryon number
fluctuations are compared to previous effective theory results, lattice results
and recent experimental data from STAR.


title: SandBlaster: Reversing the Apple Sandbox

abstract:
  In order to limit the damage of malware on Mac OS X and iOS, Apple uses
sandboxing, a kernel-level security layer that provides tight constraints for
system calls. Particularly used for Apple iOS, sandboxing prevents apps from
executing potentially dangerous actions, by defining rules in a sandbox
profile. Investigating Apple's built-in sandbox profiles is difficult as they
are compiled and stored in binary format. We present SandBlaster, a software
bundle that is able to reverse/decompile Apple binary sandbox profiles to their
original human readable SBPL (SandBox Profile Language) format. We use
SandBlaster to reverse all built-in Apple iOS binary sandbox profiles for iOS
7, 8 and 9. Our tool is, to the best of our knowledge, the first to provide a
full reversing of the Apple sandbox, shedding light into the inner workings of
Apple sandbox profiles and providing essential support for security researchers
and professionals interested in Apple security mechanisms.


title:
Emergence of particle clusters in a one-dimensional model: connection to
  condensation processes

abstract:
  We discuss a simple model of particles hopping in one dimension with
attractive interactions. Taking a hydrodynamic limit in which the interaction
strength increases with the system size, we observe the formation of multiple
clusters of particles, each containing a finite fraction of the all the
particles in the system. These clusters are correlated in space, and the system
has a self-similar (fractal) structure. These results are related to
condensation phenomena in mass transport models and to a recent mathematical
analysis of the hydrodynamic limit in a related model.


title: On quantum additive Gaussian noise channels

abstract:
  We give necessary and sufficient conditions for a Gaussian quantum channel to
have a dilation involving a passive, i.e., number-preserving unitary. We then
establish a normal form of such channels: any passively dilatable channel is
the result of applying passive unitaries to the input and output of a Gaussian
additive channel. The latter combine the state of the system with that of the
environment by means of a multi-mode beamsplitter.


title: A note on connected formula for form factors

abstract:
  In this note we study the connected prescription, originally derived from
Witten's twistor string theory, for tree-level form factors in ${\cal N}=4$
super-Yang-Mills theory. The construction is based on the recently proposed
four-dimensional scattering equations with $n$ massless on-shell states and one
off-shell state, which we expect to work for form factors of general operators.
To illustrate the universality of the prescription, we propose compact formulas
for super form factors with chiral stress-tensor multiplet operator, and
bosonic ones with scalar operators ${\rm Tr}(\phi^m)$ for arbitrary $m$.


title: Transitive Hashing Network for Heterogeneous Multimedia Retrieval

abstract:
  Hashing has been widely applied to large-scale multimedia retrieval due to
the storage and retrieval efficiency. Cross-modal hashing enables efficient
retrieval from database of one modality in response to a query of another
modality. Existing work on cross-modal hashing assumes heterogeneous
relationship across modalities for hash function learning. In this paper, we
relax the strong assumption by only requiring such heterogeneous relationship
in an auxiliary dataset different from the query/database domain. We craft a
hybrid deep architecture to simultaneously learn the cross-modal correlation
from the auxiliary dataset, and align the dataset distributions between the
auxiliary dataset and the query/database domain, which generates transitive
hash codes for heterogeneous multimedia retrieval. Extensive experiments
exhibit that the proposed approach yields state of the art multimedia retrieval
performance on public datasets, i.e. NUS-WIDE, ImageNet-YahooQA.


title:
On the new braking index of PSR B0540-69: further support for magnetic
  field growth of neutron stars following submergence by fallback accretion

abstract:
  The magnetic fields of the nascent neutron stars could be submerged in the
crust by rapid fallback accretion and could diffuse to the surface later in
life. According to this field burial scenario young pulsars may have growing
magnetic fields, a process known to result with less-than-three braking
indices; larger braking indices implying longer field-growth time-scales. A
nascent neutron star with a larger kick velocity would accrete less amount of
matter leading to a shallower burial of its field and a more rapid field
growth. Such an inverse relation between the field growth time-scale inferred
from the braking indices and space velocity of pulsars was claimed in the past
as a prediction of the field-burial scenario. With a braking index of $n\sim 2$
and large space velocity PSR~B0540--69 was then an outlier in the claimed
relation. The object recently made a transition to a rapid spin-down state
accompanied by a low braking index. This new braking index implies a much
shorter time-scale for the field growth which is consistent with the high space
velocity of the object, in better agreement with the claimed relation. This
observation lends support to the field burial scenario and implies that the
growth of the magnetic field does not proceed at a constant pace but is slowed
or completely halted at times. The slow spin-down state associated with the
high braking index before 2011 which lasted for at least about 30 years was
then such an episode of slow field growth.


title: Graph Distances and Controllability of Networks

abstract:
  In this technical note, we study the controllability of diffusively coupled
networks from a graph theoretic perspective. We consider leader-follower
networks, where the external control inputs are injected to only some of the
agents, namely the leaders. Our main result relates the controllability of such
systems to the graph distances between the agents. More specifically, we
present a graph topological lower bound on the rank of the controllability
matrix. This lower bound is tight, and it is applicable to systems with
arbitrary network topologies, coupling weights, and number of leaders. An
algorithm for computing the lower bound is also provided. Furthermore, as a
prominent application, we present how the proposed bound can be utilized to
select a minimal set of leaders for achieving controllability, even when the
coupling weights are unknown.


title:
Physical properties of single crystalline $R$Mg$_{2}$Cu$_{9}$ ($R$ = Y,
  Ce-Nd, Gd-Dy, Yb) and the search for in-plane magnetic anisotropy in
  hexagonal systems

abstract:
  Single crystals of $R$Mg$_{2}$Cu$_{9}$ ($R$=Y, Ce-Nd, Gd-Dy, Yb) were grown
using a high-temperature solution growth technique and were characterized by
measurements of room-temperature x-ray diffraction, temperature-dependent
specific heat and temperature-, field-dependent resistivity and anisotropic
magnetization. YMg$_{2}$Cu$_{9}$ is a non-local-moment-bearing metal with an
electronic specific heat coefficient, $\gamma \sim$ 15 mJ/mol K$^2$. Yb is
divalent and basically non-moment bearing in YbMg$_{2}$Cu$_{9}$. Ce is
trivalent in CeMg$_{2}$Cu$_{9}$ with two magnetic transitions being observed at
2.1 K and 1.5 K. PrMg$_{2}$Cu$_{9}$ does not exhibit any magnetic phase
transition down to 0.5 K. The other members being studied ($R$=Nd, Gd-Dy) all
exhibits antiferromagnetic transitions at low-temperatures ranging from 3.2 K
for NdMg$_{2}$Cu$_{9}$ to 11.9 K for TbMg$_{2}$Cu$_{9}$. Whereas
GdMg$_{2}$Cu$_{9}$ is isotropic in its paramagnetic state due to zero angular
momentum ($L$=0), all the other local-moment-bearing members manifest an
anisotropic, planar magnetization in their paramagnetic states. To further
study this planar anisotropy, detailed angular-dependent magnetization was
carried out on magnetically diluted (Y$_{0.99}$Tb$_{0.01}$)Mg$_{2}$Cu$_{9}$ and
(Y$_{0.99}$Dy$_{0.01}$)Mg$_{2}$Cu$_{9}$. Despite the strong, planar
magnetization anisotropy, the in-plane magnetic anisotropy is weak and
field-dependent. A set of crystal electric field parameters are proposed to
explain the observed magnetic anisotropy.


title:
Optimal Control of Connected Automated Vehicles at Urban Traffic
  Intersections: A Feasibility Enforcement Analysis

abstract:
  Earlier work has established a decentralized optimal control framework for
coordinating online a continuous flow of connected automated vehicles (CAVs)
entering a control zone and crossing two adjacent intersections in an urban
area. A solution, when it exists, allows the vehicles to cross the
intersections without the use of traffic lights, without creating congestion on
the connecting road, and under the hard safety constraint of collision
avoidance. We establish the conditions under which such solutions exist and
show that they can be enforced through an appropriately designed feasibility
enforcement zone that precedes the control zone. The proposed solution and
overall control architecture are illustrated through simulation.


title: Horizon-T Experiment Calibrations -- Cables

abstract:
  An innovative detector system called Horizon-T is constructed to study
Extensive Air Showers (EAS) in the energy range above 10^16 eV coming from a
wide range of zenith angles (0o - 85o). The system is located at Tien Shan
high-altitude Science Station of Lebedev Physical Institute of the Russian
Academy of Sciences at approximately 3340 meters above the sea level. The
detector consists of eight charged particle detection points separated by the
distance up to one kilometer as well as optical detector to view the
Vavilov-Cherenkov light from the EAS. Each detector connects to the Data
Acquisition system via cables. The calibration of the time delay for each cable
and the signal attenuation is provided in this article.


title: Bringing order to the expanding fermion zoo

abstract:
  Crystallography provides an inventory of the electron-like particles that
emerge in a lattice world. Perspective for Science on arXiv:1603.03093


title: Weakly Supervised Object Localization Using Size Estimates

abstract:
  We present a technique for weakly supervised object localization (WSOL),
building on the observation that WSOL algorithms usually work better on images
with bigger objects. Instead of training the object detector on the entire
training set at the same time, we propose a curriculum learning strategy to
feed training images into the WSOL learning loop in an order from images
containing bigger objects down to smaller ones. To automatically determine the
order, we train a regressor to estimate the size of the object given the whole
image as input. Furthermore, we use these size estimates to further improve the
re-localization step of WSOL by assigning weights to object proposals according
to how close their size matches the estimated object size. We demonstrate the
effectiveness of using size order and size weighting on the challenging PASCAL
VOC 2007 dataset, where we achieve a significant improvement over existing
state-of-the-art WSOL techniques.


title: On a strange evaluation of the hypergeometric series by Gosper. II

abstract:
  There are many identities for the hypergeometric series presented in the
article "Special values of the hypergeometric series" by Ebisu. In this note,
we obtain a new hypergeometric identity, which includes some of these
identities as special cases. We notice that this identity closely relates to a
strange evaluation by Gosper.
  Key Words and Phrases: the hypergeometric series, hypergeometric identity.


title:
Superconductor to Mott insulator transition in
  YBa$_2$Cu$_3$O$_7$/LaCaMnO$_3$ heterostructures

abstract:
  The superconductor-to-insulator transition (SIT) induced by means such as
external magnetic fields, disorder or spatial confinement is a vivid
illustration of a quantum phase transition dramatically affecting the
superconducting order parameter. In pursuit of a new realization of the SIT by
interfacial charge transfer, we developed extremely thin superlattices composed
of high $T_c$ superconductor YBa$_2$Cu$_3$O$_7$ (YBCO) and colossal
magnetoresistance ferromagnet La$_{0.67}$Ca$_{0.33}$MnO$_3$ (LCMO). By using
linearly polarized resonant X-ray absorption spectroscopy and magnetic circular
dichroism, combined with hard X-ray photoelectron spectroscopy, we derived a
complete picture of the interfacial carrier doping in cuprate and manganite
atomic layers, leading to the transition from superconducting to an unusual
Mott insulating state emerging with the increase of LCMO layer thickness. In
addition, contrary to the common perception that only transition metal ions may
response to the charge transfer process, we found that charge is also actively
compensated by rare-earth and alkaline-earth metal ions of the interface. Such
deterministic control of $T_c$ by pure electronic doping without any hindering
effects of chemical substitution is another promising route to disentangle the
role of disorder on the pseudo-gap and charge density wave phases of underdoped
cuprates.


title:
Non-equilibrium and stationary fluctuations of a slowed boundary
  symmetric exclusion

abstract:
  We consider a one-dimensional symmetric simple exclusion process in contact
with slowed reservoirs: at the left (resp. right) boundary, particles are
either created or removed at rates given by $\alpha/n$ or $(1-\alpha)/n$ (resp.
$\beta/n$ or $(1-\beta)/n$) where $\alpha, \beta>0$ and $n$ is a scaling
parameter. We obtain the non-equilibrium fluctuations and consequently the
non-equilibrium stationary fluctuations.


title:
Hydrodynamic modeling of a pure-glue initial scenario in high-energy
  hadron and heavy-ion collisions

abstract:
  Partonic matter produced in the early stage of ultrarelativistic
nucleus-nucleus collisions is assumed to be composed mainly of gluons, and
quarks and antiquarks are produced at later times. The comparable hydrodynamic
simulations of heavy-ion collisions for (2+1)-flavor and Yang-Mills equations
of state performed by using three different hydrodynamic codes are presented.
Assuming slow chemical equilibration of quarks, the spectra and elliptic flows
of thermal dileptons and photons are calculated for central Pb+Pb collisions at
the LHC energy of $\sqrt{s_{_{\rm NN}}} = 2.76$ TeV. It is shown that a
suppression of quarks at early times leads to a significant reduction of the
yield of the thermal dileptons, but only to a rather modest suppression of the
$p_T$-distribution of direct photons. It is demonstrated that an enhancement of
photon and dilepton elliptic flows might serve as a promising signature of the
pure-glue initial state. Calculations based on Bjorken hydrodynamics suggest
that collisions of small systems at intermediate energies available at RHIC or
future FAIR facilities may show stronger effects associated with initial pure
gluodynamic evolution.