title:
Future CMB tests of dark matter: ultra-light axions and massive
  neutrinos

abstract:
  Measurements of cosmic microwave background (CMB) anisotropies provide strong
evidence for the existence of dark matter and dark energy. They can also test
its composition, probing the energy density and particle mass of different
dark-matter and dark-energy components. CMB data have already shown that
ultra-light axions (ULAs) with mass in the range $10^{-32}~{\rm eV} \to
10^{-26}~{\rm eV}$ compose a fraction $< 0.01$ of the cosmological critical
density. Here, the sensitivity of a proposed CMB-Stage IV (CMB-S4) experiment
(assuming a 1 arcmin beam and $< 1~\mu K{\rm-arcmin}$ noise levels over a sky
fraction of 0.4) to the density of ULAs and other dark-sector components is
assessed. CMB-S4 data should be $\sim 10$ times more sensitive to the ULA
energy-density than Planck data alone, across a wide range of ULA masses
$10^{-32}< m_{a}< 10^{-23}~{\rm eV}$, and will probe axion decay constants of
$f_{a}\approx 10^{16}~{\rm GeV}$, at the grand unified scale. CMB-S4 could
improve the CMB lower bound on the ULA mass from $\sim 10^{-25}~{\rm eV}$ to
$10^{-23}~{\rm eV}$, nearing the mass range probed by dwarf galaxy abundances
and dark-matter halo density profiles. These improvements will allow for a
multi-$\sigma$ detection of percent-level departures from CDM over a wide range
of masses. Much of this improvement is driven by the effects of weak
gravitational lensing on the CMB, which breaks degeneracies between ULAs and
neutrinos. We also find that the addition of ULA parameters does not
significantly degrade the sensitivity of the CMB to neutrino masses. These
results were obtained using the axionCAMB code (a modification to the CAMB
Boltzmann code), presented here for public use.


title:
Robust Causal Transform Coding for LQG Systems with Delay Loss in
  Communications

abstract:
  A networked controlled system (NCS) in which the plant communicates to the
controller over a channel with random delay loss is considered. The channel
model is motivated by recent development of tree codes for NCS, which
effectively translates an erasure channel to one with random delay. A causal
transform coding scheme is presented which exploits the plant state memory for
efficient communications (compression) and provides robustness to channel delay
loss. In this setting, we analyze the performance of linear quadratic Gaussian
(LQG) closed-loop systems and the design of the optimal controller. The design
of the transform code for LQG systems is posed as a channel optimized source
coding problem of minimizing a weighted mean squared error over the channel.
The solution is characterized in two steps of obtaining the optimized causal
encoding and decoding transforms and rate allocation across a set of transform
coding quantizers. Numerical and simulation results for Gauss-Markov sources
and an LQG system demonstrate the effectiveness of the proposed schemes.


title:
Circularly polarized lasing in chiral modulated semiconductor
  microcavity with GaAs quantum wells

abstract:
  We report the elliptically, close to circularly polarized lasing at
$\hbar\omega = 1.473$ and 1.522 eV from an AlAs/AlGaAs Bragg microcavity with
12 GaAs quantum wells in the active region and chiral-etched upper distributed
Bragg refractor under optical pump at room temperature. The advantage of using
the chiral photonic crystal with a large contrast of dielectric permittivities
is its giant optical activity, allowing to fabricate a very thin half-wave
plate, with a thickness of the order of the emitted light wavelength, and to
realize the monolithic control of circular polarization.


title: Selective Inference for Group-Sparse Linear Models

abstract:
  We develop tools for selective inference in the setting of group sparsity,
including the construction of confidence intervals and p-values for testing
selected groups of variables. Our main technical result gives the precise
distribution of the magnitude of the projection of the data onto a given
subspace, and enables us to develop inference procedures for a broad class of
group-sparse selection methods, including the group lasso, iterative hard
thresholding, and forward stepwise regression. We give numerical results to
illustrate these tools on simulated data and on health record data.


title: arXiv@25: Key findings of a user survey

abstract:
  As part of its 25th anniversary vision-setting process, the arXiv team at
Cornell University Library conducted a user survey in April 2016 to seek input
from the global user community about arXiv's current services and future
directions. We were heartened to receive 36,000 responses from 127 countries,
representing arXiv's diverse, global community. The prevailing message is that
users are happy with the service as it currently stands, with 95 percent of
survey respondents indicating they are very satisfied or satisfied with arXiv.
Furthermore, 72 percent of respondents indicated that arXiv should continue to
focus on its main purpose, which is to quickly make available scientific
papers, and this will be enough to sustain the value of arXiv in the future.
This theme was pervasively reflected in the open text comments; a significant
number of respondents suggested remaining focused on the core mission and
enabling arXiv's partners and related service providers to continue to build
new services and innovations on top of arXiv.


title:
Global numerical simulations of the rise of vortex-mediated pulsar
  glitches in full general relativity

abstract:
  In this paper, we study in detail the role of general relativity on the
global dynamics of giant pulsar glitches as exemplified by Vela. For this
purpose, we carry out numerical simulations of the spin up triggered by the
sudden unpinning of superfluid vortices. In particular, we compute the exchange
of angular momentum between the core neutron superfluid and the rest of the
star within a two-fluid model including both (non-dissipative) entrainment
effects and (dissipative) mutual friction forces. Our simulations are based on
a quasi-stationary approach using realistic equations of state (EoSs). We show
that the evolution of the angular velocities of both fluids can be accurately
described by an exponential law. The associated characteristic rise time
$\tau_{\text{r}}$, which can be precisely computed from stationary
configurations only, has a form similar to that obtained in the Newtonian
limit. However, general relativity changes the structure of the star and leads
to additional couplings between the fluids due to frame-dragging effects. As a
consequence, general relativity can have a large impact on the actual value of
$\tau_{\text{r}}$: the errors incurred by using Newtonian gravity are thus
found to be as large as $\sim 40 \%$ for the models considered. Values of the
rise time are calculated for Vela and compared with current observational
limits. Finally, we study the amount of gravitational waves emitted during a
glitch. Simple expressions are obtained for the corresponding characteristic
amplitudes and frequencies. The detectability of glitches through gravitational
wave observatories is briefly discussed.


title: Asymmetric volatility connectedness on forex markets

abstract:
  We show how bad and good volatility propagate through forex markets, i.e., we
provide evidence for asymmetric volatility connectedness on forex markets.
Using high-frequency, intra-day data of the most actively traded currencies
over 2007 - 2015 we document the dominating asymmetries in spillovers that are
due to bad rather than good volatility. We also show that negative spillovers
are chiefly tied to the dragging sovereign debt crisis in Europe while positive
spillovers are correlated with the subprime crisis, different monetary policies
among key world central banks, and developments on commodities markets. It
seems that a combination of monetary and real-economy events is behind the net
positive asymmetries in volatility spillovers, while fiscal factors are linked
with net negative spillovers.


title: Congestion Relief and Load Curtailment Reduction with FACTS Devices

abstract:
  This paper investigates the effect of FACTS Devices on voltage stability
constrained Optimal Power Flow (OPF) formulation where the objective function
is to minimize power system load curtailment. Incorporating FACTS Devices
affects the topology and hence the power flow distribution. Some numerical
cases are presented to discuss the effects of FACTS Devices that is expected
when it is incorporated into the load curtailment formulation. The test result
reflects the impacts FACTS Devices has in reducing load curtailment during a
line congestion situation. The paper also discusses the applicability of
approach in security based reliability studies for systems having control
components like FACTS Devices.


title:
Congestion Management by a Real-Time Optimal Dispatch through Balancing
  Mechanism Method for Electricity Markets

abstract:
  A real-time optimal dispatch method for unbundle electricity markets is
proposed in this paper. With this method, pool energy auction market, ancillary
services market, and bilateral contract market can be coordinated by the ISO
through a balancing market for the purpose of system security. To meet
real-time imbalance and to eliminate transmission congestion, operating
reserves, curtailment of bilateral contracts, and supplemental energy bids in
the real-time balancing market (REM), can all be called upon in light of their
bidding prices. The replacement of the operating reserves used to provide
balancing energy is incorporated into the objective of the real-time optimal
dispatch problem. A modified P-Q decoupled optimal power flow (OPF) is employed
to implement this method. Spot pricing for the real-time dispatch is presented.
The IEEE 30-bus test system is studied to illustrate the proposed framework.


title:
Optimal Price and Quantity Determination of Retailer Electric Contract
  and maximizing social welfare in Retail Electrical Power Markets with DG

abstract:
  Retail electrical power marketers, also known as retailers, typically set up
contracts with suppliers to secure electricity at fixed prices on the one hand
and with end users to meet their load requirements at agreed rates on the other
hand. Also high penetration of distributed generation (DG) resource is
increasingly observed worldwide. Considering the viewpoint of a retailer, this
paper analyzes the problem of setting up contracts on both the supplier and
end-user sides to maximize profits while maintaining a minimum operational cost
of distribution system. The proposed two-level optimization models can minimize
the cost of distribution system with Distributed Generation and maximize the
profits of retailers. The numerical simulations are carried out based on an
IEEE 33-bus test distribution network. Test results are included to show the
performance of the proposed method.


title: Non-Convex Phase Retrieval from STFT Measurements

abstract:
  The problem of recovering a one-dimensional signal from its Fourier transform
magnitude, called Fourier phase retrieval, is ill-posed in most cases. We
consider the closely-related problem of recovering a signal from its phaseless
short-time Fourier transform (STFT) measurements. This problem arises naturally
in several applications, such as ultra-short laser pulse characterization and
ptychography. The redundancy offered by the STFT enables unique recovery under
mild conditions. We show that in some cases the unique solution can be obtained
by the principal eigenvector of a matrix, constructed as the solution of a
simple least-squares problem. When these conditions are not met, we suggest
using the principal eigenvector of this matrix to initialize non-convex local
optimization algorithms and propose two such methods. The first is based on
minimizing the empirical risk loss function, while the second maximizes a
quadratic function on the manifold of phases. We prove that under appropriate
conditions, the proposed initialization is close to the underlying signal. We
then analyze the geometry of the empirical risk loss function and show
numerically that both gradient algorithms converge to the underlying signal
even with small redundancy in the measurements. In addition, the algorithms are
robust to noise.


title: Building Cosmological Frozen Stars

abstract:
  Janis-Newman-Winicour (JNW) spacetimes generalize the Schwarzschild solution
to include a massless scalar field. Although suffering from naked
singularities, they share the `frozen star' features of Schwarzschild black
holes. Cosmological versions of the JNW spacetimes were discovered some time
ago by Husain, Martinez and Nunez and by Fonarev. Unlike Schwarzschild-deSitter
black holes, these solutions are dynamical, and the scarcity of exact solutions
for dynamical black holes in cosmological backgrounds motivates their further
study. Here we show how the cosmological JNW spacetimes can be built, starting
from simpler, static, higher dimensional, vacuum `JNW brane' solutions via two
different generalized dimensional reduction schemes that together cover the
full range of JNW parameter space. Cosmological versions of a BPS limit of
charged dilaton black holes are also known. JNW spacetimes represent a
different limiting case of the charged, dilaton black hole family. We expect
that understanding this second data point may be key to finding cosmological
versions of general, non-BPS black holes.


title:
PANDA: Extreme Scale Parallel K-Nearest Neighbor on Distributed
  Architectures

abstract:
  Computing $k$-Nearest Neighbors (KNN) is one of the core kernels used in many
machine learning, data mining and scientific computing applications. Although
kd-tree based $O(\log n)$ algorithms have been proposed for computing KNN, due
to its inherent sequentiality, linear algorithms are being used in practice.
This limits the applicability of such methods to millions of data points, with
limited scalability for Big Data analytics challenges in the scientific domain.
In this paper, we present parallel and highly optimized kd-tree based KNN
algorithms (both construction and querying) suitable for distributed
architectures. Our algorithm includes novel approaches for pruning search space
and improving load balancing and partitioning among nodes and threads. Using
TB-sized datasets from three science applications: astrophysics, plasma
physics, and particle physics, we show that our implementation can construct
kd-tree of 189 billion particles in 48 seconds on utilizing $\sim$50,000 cores.
We also demonstrate computation of KNN of 19 billion queries in 12 seconds. We
demonstrate almost linear speedup both for shared and distributed memory
computers. Our algorithms outperforms earlier implementations by more than
order of magnitude; thereby radically improving the applicability of our
implementation to state-of-the-art Big Data analytics problems. In addition, we
showcase performance and scalability on the recently released Intel Xeon Phi
processor showing that our algorithm scales well even on massively parallel
architectures.


title: MS-Celeb-1M: A Dataset and Benchmark for Large-Scale Face Recognition

abstract:
  In this paper, we design a benchmark task and provide the associated datasets
for recognizing face images and link them to corresponding entity keys in a
knowledge base. More specifically, we propose a benchmark task to recognize one
million celebrities from their face images, by using all the possibly collected
face images of this individual on the web as training data. The rich
information provided by the knowledge base helps to conduct disambiguation and
improve the recognition accuracy, and contributes to various real-world
applications, such as image captioning and news video analysis. Associated with
this task, we design and provide concrete measurement set, evaluation protocol,
as well as training data. We also present in details our experiment setup and
report promising baseline results. Our benchmark task could lead to one of the
largest classification problems in computer vision. To the best of our
knowledge, our training dataset, which contains 10M images in version 1, is the
largest publicly available one in the world.


title: Microresonator Soliton Dual-Comb Spectroscopy

abstract:
  Rapid characterization of optical and vibrational spectra with high
resolution can identify species in cluttered environments and is important for
assays and early alerts. In this regard, dual-comb spectroscopy has emerged as
a powerful approach to acquire nearly instantaneous Raman and optical spectra
with unprecedented resolution. Spectra are generated directly in the electrical
domain and avoid bulky mechanical spectrometers. Recently, a miniature
soliton-based comb has emerged that can potentially transfer the dual-comb
method to a chip platform. Unlike earlier microcombs, these new devices achieve
high-coherence, pulsed mode locking. They generate broad, reproducible spectral
envelopes, which is essential for dual-comb spectroscopy. Here, dual-comb
spectroscopy is demonstrated using these devices. This work shows the potential
for integrated, high signal-to-noise spectroscopy with fast acquisition rates.


title: Stronger uncertainty relations with improvable upper and lower bounds

abstract:
  We utilize quantum superposition principle to establish the improvable upper
and lower bounds on the stronger uncertainty relation, i.e., the
"weighted-like" sum of the variances of observables. Our bounds include some
free parameters which not only guarantee the nontrivial bounds but also can
effectively control the bounds as tightly as one expects. Especially, these
parameters don't obviously depend on the state and observables. It also implies
one advantage of our method that any nontrivial bound can always be more
improvable. In addition, we generalize both bounds to the uncertainty relation
with multiple observables, but the perfect tightness is not changed. Examples
are given to illustrate the improvability of our bounds in each case.


title: Interactional Expertise and Embodiment

abstract:
  In Part 1 of this paper, I introduce the idea of interactional expertise
while in Part 2, I focus on its implications for philosophical theories of the
importance of the body in forming our conceptual world. I argue that the way
philosophers have dealt with the body turns attention away from the most
important questions and that we cannot answer these questions without making
the notion of socialisation, and therefore interactional expertise, a central
concept in our thinking. This makes language at least as important, and often
more important than bodily practice in our understanding of the world. The
notion of a disembodied socialised agent leads in the direction of interesting
questions while the notion of an embodied but unsocialised human actor is
unimaginable.


title: A non-Levi branching rule in terms of Littelmann paths

abstract:
  We prove a conjecture of Naito-Sagaki about a branching rule for the
restriction of irreducible representations of $\mathfrak{sl}(2n,\mathbb{C})$ to
$\mathfrak{sp}(2n,\mathbb{C})$. The conjecture is in terms of certain
Littelmann paths, with the embedding given by the folding of the type
$A_{2n-1}$ Dynkin diagram.


title: Automatic complexity of shift register sequences

abstract:
  Let $x$ be an $m$-sequence, a maximal length sequence produced by a linear
feedback shift register. We show that $x$ has maximal subword complexity
function in the sense of Allouche and Shallit. We show that this implies that
the nondeterministic automatic complexity $A_N(x)$ is close to maximal:
$n/2-A_N(x)=O(\log^2n)$, where $n$ is the length of $x$. In contrast, Hyde has
shown $A_N(y)\le n/2+1$ for all sequences $y$ of length $n$.


title: Open and Regionalised Spectrum Repositories for Emerging Countries

abstract:
  TV White Spaces have recently been proposed as an alternative to alleviate
the spectrum crunch, characterised by the need to reallocate frequency bands to
accommodate the ever-growing demand for wireless communications. In this paper,
we discuss the motivations and challenges for collecting spectrum measurements
in developing regions and discuss a scalable system for communities to gather
and provide access to White Spaces information through open and regionalised
repositories. We further discuss two relevant aspects. First, we propose a
cooperative mechanism for sensing spectrum availability using a detector
approach. Second, we propose a strategy (and an architecture) on the database
side to implement spectrum governance. Other aspects of the work include
discussion of an extensive measurement campaign showing a number of white
spaces in developing regions, an overview of our experience on low-cost
spectrum analysers, and the architecture of zebra-rfo, an application for
processing crowd-sourced spectrum data.


title: LightDP: Towards Automating Differential Privacy Proofs

abstract:
  The growing popularity and adoption of differential privacy in academic and
industrial settings has resulted in the development of increasingly
sophisticated algorithms for releasing information while preserving privacy.
Accompanying this phenomenon is the natural rise in the development and
publication of incorrect algorithms, thus demonstrating the necessity of formal
verification tools. However, existing formal methods for differential privacy
face a dilemma: methods based on customized logics can verify sophisticated
algorithms but come with a steep learning curve and significant annotation
burden on the programmers, while existing programming platforms lack expressive
power for some sophisticated algorithms.
  In this paper, we present LightDP, a simple imperative language that strikes
a better balance between expressive power and usability. The core of LightDP is
a novel relational type system that separates relational reasoning from privacy
budget calculations. With dependent types, the type system is powerful enough
to verify sophisticated algorithms where the composition theorem falls short.
In addition, the inference engine of LightDP infers most of the proof details,
and even searches for the proof with minimal privacy cost bound when multiple
proofs exist. We show that LightDP verifies sophisticated algorithms with
little manual effort.


title: Double Quantum Dot Floquet Gain Medium

abstract:
  Strongly driving a two-level quantum system with light leads to a ladder of
Floquet states separated by the photon energy. Nanoscale quantum devices allow
the interplay of confined electrons, phonons, and photons to be studied under
strong driving conditions. Here we show that a single electron in a
periodically driven DQD functions as a "Floquet gain medium," where population
imbalances in the DQD Floquet quasi-energy levels lead to an intricate pattern
of gain and loss features in the cavity response. We further measure a large
intra-cavity photon number n_c in the absence of a cavity drive field, due to
equilibration in the Floquet picture. Our device operates in the absence of a
dc current -- one and the same electron is repeatedly driven to the excited
state to generate population inversion. These results pave the way to future
studies of non-classical light and thermalization of driven quantum systems.


title:
Singularities of plane complex curves and limits of K\"ahler metrics
  with cone singularities. I: Tangent Cones

abstract:
  We construct and classify, in the case of two complex dimensions, the
possible tangent cones at points of limit spaces of non-collapsed sequences of
K\"ahler-Einstein metrics with cone singularities.


title: Moduli Backreaction on Inflationary Attractors

abstract:
  We investigate the interplay between moduli dynamics and inflation, focusing
on the KKLT-scenario and cosmological $\alpha$-attractors. General couplings
between these sectors can induce a significant backreaction and potentially
destroy the inflationary regime; however, we demonstrate that this generically
does not happen for $\alpha$-attractors. Depending on the details of the
superpotential, the volume modulus can either be stable during the entire
inflationary trajectory, or become tachyonic at some point and act as a
waterfall field, resulting in a sudden end of inflation. In the latter case
there is a universal supersymmetric minimum where the scalars end up,
preventing the decompactification scenario. The gravitino mass is independent
from the inflationary scale with no fine-tuning of the parameters. The
observational predictions conform to the universal value of attractors, fully
compatible with the Planck data, with possibly a capped number of e-folds due
to the interplay with moduli.


title: Radio Detection of High Energy Neutrinos

abstract: This is a review on radio detection of high energy neutrinos.


title: A hierarchy of simple hyperbolic two-fluid models for bubbly flows

abstract:
  With the objective of modeling both separate and disperse two-phase flows, we
use in this paper a methodology for deriving two-fluid models that do not
assume any flow topology. This methodology is based on a variational principle
and on entropy dissipation requirement. Some of the models that are such
derived and studied are already known in the contexts of the description of
separate-or disperse-phase flows. However, we here propose an arrangement of
these models into a hierarchy based on their links through relaxation
parameters. Moreover, the models are shown to be compatible with the
description of a monodisperse bubbly flow and, within this frame, the
relaxation parameters can be identified. This identification is finally
verified and discussed through comparisons with experimental measures of sound
dispersion and with dispersion relations of a reference model for bubbly media.


title: Rainbow's Stars

abstract:
  In recent years, a growing interest on the equilibrium of compact
astrophysical objects like white dwarf and neutron stars has been manifested.
In particular, various modifications due to Planck scale energy effects have
been considered. In this paper we analyze the modification induced by Gravity's
Rainbow on the equilibrium configurations described by the
Tolman-Oppenheimer-Volkoff (TOV) equation. Our purpose is to explore the
possibility that the Rainbow Planck-scale deformation of space-time could
support the existence of different compact stars.


title: Comment on "proactive quantum secret sharing"

abstract:
  In the paper [Quantum Inf. Process. 14, 4237-4244 (2015)], Qin and Dai
proposed a proactive quantum secret sharing scheme. We study the security of
the proposed scheme and find that it is not secure. In the distribution phase
of the proposed scheme, two dishonest participants may collaborate to eavesdrop
the secret of the dealer without introducing any error. Incidentally, a
possible improvement of the distribution phase is given.


title: Adaptive foveated single-pixel imaging with dynamic super-sampling

abstract:
  As an alternative to conventional multi-pixel cameras, single-pixel cameras
enable images to be recorded using a single detector that measures the
correlations between the scene and a set of patterns. However, to fully sample
a scene in this way requires at least the same number of correlation
measurements as there are pixels in the reconstructed image. Therefore
single-pixel imaging systems typically exhibit low frame-rates. To mitigate
this, a range of compressive sensing techniques have been developed which rely
on a priori knowledge of the scene to reconstruct images from an under-sampled
set of measurements. In this work we take a different approach and adopt a
strategy inspired by the foveated vision systems found in the animal kingdom -
a framework that exploits the spatio-temporal redundancy present in many
dynamic scenes. In our single-pixel imaging system a high-resolution foveal
region follows motion within the scene, but unlike a simple zoom, every frame
delivers new spatial information from across the entire field-of-view. Using
this approach we demonstrate a four-fold reduction in the time taken to record
the detail of rapidly evolving features, whilst simultaneously accumulating
detail of more slowly evolving regions over several consecutive frames. This
tiered super-sampling technique enables the reconstruction of video streams in
which both the resolution and the effective exposure-time spatially vary and
adapt dynamically in response to the evolution of the scene. The methods
described here can complement existing compressive sensing approaches and may
be applied to enhance a variety of computational imagers that rely on
sequential correlation measurements.


title: The population of long-period transiting exoplanets

abstract:
  The Kepler Mission has discovered thousands of exoplanets and revolutionized
our understanding of their population. This large, homogeneous catalog of
discoveries has enabled rigorous studies of the occurrence rate of exoplanets
and planetary systems as a function of their physical properties. However,
transit surveys like Kepler are most sensitive to planets with orbital periods
much shorter than the orbital periods of Jupiter and Saturn, the most massive
planets in our Solar System. To address this deficiency, we perform a fully
automated search for long-period exoplanets with only one or two transits in
the archival Kepler light curves. When applied to the $\sim 40,000$ brightest
Sun-like target stars, this search produces 16 long-period exoplanet
candidates. Of these candidates, 6 are novel discoveries and 5 are in systems
with inner short-period transiting planets. Since our method involves no human
intervention, we empirically characterize the detection efficiency of our
search. Based on these results, we measure the average occurrence rate of
exoplanets smaller than Jupiter with orbital periods in the range 2-25 years to
be $2.0\pm0.7$ planets per Sun-like star.


title: Field-induced decays in $XXZ$ triangular-lattice antiferromagnets

abstract:
  We investigate field-induced transformations in the dynamical response of the
$XXZ$ model on the triangular lattice that are associated with the anharmonic
magnon coupling and decay phenomena. A set of concrete theoretical predictions
is made for a close physical realization of the spin-1/2 $XXZ$ model,
Ba$_3$CoSb$_2$O$_9$. We demonstrate that dramatic modifications in magnon
spectrum must occur in low out-of-plane fields that are easily achievable for
this material. The hallmark of the effect is a coexistence of the clearly
distinct well-defined magnon excitations with significantly broadened ones in
different regions of the ${\bf k}-\omega$ space. The field-induced decays are
generic for this class of models and become more prominent at larger
anisotropies and in higher fields.


title:
The International Deep Planet Survey II: The frequency of directly
  imaged giant exoplanets with stellar mass

abstract:
  Radial velocity and transit methods are effective for the study of short
orbital period exoplanets but they hardly probe objects at large separations
for which direct imaging can be used. We carried out the international deep
planet survey of 292 young nearby stars to search for giant exoplanets and
determine their frequency. We developed a pipeline for a uniform processing of
all the data that we have recorded with NIRC2/Keck II, NIRI/Gemini North,
NICI/Gemini South, and NACO/VLT for 14 years. The pipeline first applies
cosmetic corrections and then reduces the speckle intensity to enhance the
contrast in the images. The main result of the international deep planet survey
is the discovery of the HR 8799 exoplanets. We also detected 59 visual multiple
systems including 16 new binary stars and 2 new triple stellar systems, as well
as 2,279 point-like sources. We used Monte Carlo simulations and the Bayesian
theorem to determine that 1.05[+2.80-0.70]% of stars harbor at least one giant
planet between 0.5 and 14M_J and between 20 and 300 AU. This result is obtained
assuming uniform distributions of planet masses and semi-major axes. If we
consider power law distributions as measured for close-in planets instead, the
derived frequency is 2.30[+5.95-1.55]%, recalling the strong impact of
assumptions on Monte Carlo output distributions. We also find no evidence that
the derived frequency depends on the mass of the hosting star, whereas it does
for close-in planets. The international deep planet survey provides a database
of confirmed background sources that may be useful for other exoplanet direct
imaging surveys. It also puts new constraints on the number of stars with at
least one giant planet reducing by a factor of two the frequencies derived by
almost all previous works.


title: IC at IC: IceCube can constrain the intrinsic charm of the proton

abstract:
  The discovery of extraterrestrial neutrinos in the $\sim$ 30 TeV -- PeV
energy range by IceCube provides new constraints on high energy astrophysics.
An important background to the signal are the prompt neutrinos which originate
from the decay of charm hadrons produced by high energy cosmic-ray particles
interacting in the Earth's atmosphere. It is conventional to use the
calculations of charm hadroproduction using gluon splitting $g \to c \bar c$
alone. However, QCD predicts an additional "intrinsic" component of the heavy
quark distribution which arises from diagrams where heavy quarks are multiply
connected to the proton's valence quarks. We estimate the prompt neutrino
spectrum due to intrinsic charm. We find that the atmospheric prompt neutrino
flux from intrinsic charm is comparable to those calculated using QCD
computations not including intrinsic charm, once we normalize the intrinsic
charm differential cross sections to the ISR and the LEBC-MPS collaboration
data. In future, IceCube will constrain the intrinsic charm content of the
proton and will contribute to one of the major questions in high energy physics
phenomenology.

categories: hep-ph astro-ph.HE hep-ex nucl-ex nucl-th


title: Regularization-scheme dependence of QCD amplitudes in the massive case

abstract:
  We investigate QCD amplitudes with massive quarks computed in the
four-dimensional helicity scheme (FDH) and dimensional reduction at NNLO and
describe how they are related to the corresponding amplitudes computed in
conventional dimensional regularization. To this end, the scheme dependence of
the heavy quark and the velocity-dependent cusp anomalous dimensions is
determined using soft-collinear effective theory. The results are checked
against explicit computations of massive form factors in FDH at NNLO. Our
results complete the description of the scheme dependence of QCD amplitudes at
NNLO.


title:
Current-loops, phase transitions, and the Higgs mechanism in
  Josephson-coupled multi-component superconductors

abstract:
  The $N$-component London $\mathrm{U}(1)$ superconductor is expressed in terms
of integer-valued supercurrents. We show that the inclusion of inter-band
Josephson couplings introduces monopoles in the current fields, which convert
the phase transitions of the charge-neutral sector to crossovers. The monopoles
only couple to the neutral sector, and leave the phase transition of the
charged sector intact. The remnant non-critical fluctuations in the neutral
sector influence the one remaining phase transition in the charged sector, and
may alter this phase transition from a $3DXY$ inverted phase transition into a
first-order phase transition depending on what the values of the gauge-charge
and the inter-component Josephson coupling are. This preemptive effect becomes
more pronounced with increasing number of components $N$, since the number of
charge-neutral fluctuating modes that can influence the charged sector
increases with $N$. We also calculate the gauge-field correlator, and by
extension the Higgs mass, in terms of current-current correlators. We show that
the onset of the Higgs-mass of the photon (Meissner-effect) is given in terms
of a current-loop blowout associated with going into the superconducting state
as the temperature of the system is lowered.


title: Three-Dimensional Majorana Fermions in Chiral Superconductors

abstract:
  Through a systematic symmetry and topology analysis we establish that
three-dimensional chiral superconductors with strong spin-orbit coupling and
odd-parity pairing generically host low-energy nodal quasiparticles that are
spin-non-degenerate and realize Majorana fermions in three dimensions. By
examining all types of chiral Cooper pairs with total angular momentum $J$
formed by Bloch electrons with angular momentum $j$ in crystals, we obtain a
comprehensive classification of gapless Majorana quasiparticles in terms of
energy-momentum relation and location on the Fermi surface. We show that the
existence of bulk Majorana fermions in the vicinity of spin-selective point
nodes is rooted in the non-unitary nature of chiral pairing in
spin-orbit-coupled superconductors. We address experimental signatures of
Majorana fermions, and find that the nuclear magnetic resonance (NMR) spin
relaxation rate is significantly suppressed for nuclear spins polarized along
the nodal direction as a consequence of the spin-selective Majorana nature of
nodal quasiparticles. Furthermore, Majorana nodes in the bulk have nontrivial
topology and imply the presence of Majorana bound states on the surface that
form arcs in momentum space. We conclude by proposing the heavy fermion
superconductor PrOs$_4$Sb$_{12}$ and related materials as promising candidates
for non-unitary chiral superconductors hosting three-dimensional Majorana
fermions.


title: Unitarity of Superstring Field Theory

abstract:
  We complete the proof of unitarity of (compactified) heterotic and type II
string field theories by showing that in the cut diagrams only physical states
appear in the sum over intermediate states. This analysis takes into account
the effect of mass and wave-function renormalization, and the possibility that
the true vacuum may be related to the perturbative vacuum by small shifts in
the string fields.


title:
Evidence of Bar-induced Secular Evolution in the Inner Regions of
  Stellar Discs in Galaxies: What Shapes Disc Galaxies?

abstract:
  We present evidence of bar-induced secular evolution in galactic discs using
3.6 ${\mu m}$ images of nearby galaxies from the Spitzer Survey of Stellar
Structure in Galaxies (S4G). We find that among massive galaxies
($M_{star}/M_{sun}> 10^{10}$), longer bars tend to reside in inner discs having
a flatter radial profile. Such galaxies show a light deficit in the disc
surrounding the bar, within the bar radius and often show a $\Theta$-shaped
morphology. We quantify this deficit and find that among all galaxies explored
in this study (with $10^{9}<M_{star}/M_{sun}< 10^{11}$), galaxies with a
stronger bar (i.e. longer and/or with a higher Bar/T) show a more pronounced
deficit. We also examine simulation snapshots to confirm and extend results by
Athanassoula and Misiriotis, showing that as bars evolve they become longer,
while the light deficit in the disc becomes more pronounced. Theoretical
studies have predicted that, as a barred galaxy evolves, the bar captures disc
stars in its immediate neighbourhood so as to make the bar longer, stronger and
thinner. Hence, we claim that the light deficit in the inner disc is produced
by bars, which thus take part in shaping the mass distribution of their host
galaxies.


title: Graviton and gluon scattering from first principles

abstract:
  Graviton and gluon scattering are studied from minimal physical assumptions
such as Poincare and gauge symmetry as well as unitarity. The assumptions lead
to an interesting and surprisingly restrictive set of linear equations. This
shows gluon and graviton scattering to be related in many field and string
theories, explaining and extending several known results. By systematic
analysis exceptional graviton scattering amplitudes are derived which in
general dimensions can not be related to gluon amplitudes. The simplicity of
the formalism guarantees wide further applicability to gauge and gravity
theories.


title:
On the decreasing fraction of Strong Ly$\alpha$ Emitters around $z$
  $\sim$ $6$-$7$

abstract:
  The fraction of galaxies with strong Ly$\alpha$ emission has been observed to
decrease rapidly with redshift at $z \ge 6$, after a gradual increase at $z<
6$. This has been interpreted as a hint of the reionization of the
intergalactic medium (IGM): the emitted Ly$\alpha$ photons would be scattered
by an increasingly neutral IGM at $z>6$. We study this effect by modeling the
ionization and Ly$\alpha$ radiative transfer in the infall region and the IGM
around a Ly$\alpha$ emitting galaxy (LAE), for a spherical halo model with the
mean density and radial velocity profiles in the standard $\Lambda$CDM
cosmological scenario. We find that the expected fast increase of the ionizing
background intensity toward the end of the reionization epoch implies a rapid
evolution of halo infall regions from being self-shielded against the external
ionizing background to being mostly ionized. Whereas self-shielded infall
regions can scatter the Ly$\alpha$ photons over a much larger area than the
commonly used apertures for observing LAEs, the same infalling gas is no longer
optically thick to the Ly$\alpha$ emission line after it is ionized by the
external background, making the Ly$\alpha$ emission more compact and brighter
within the observed apertures. Based on this simple model, we show that the
observed drop in the abundance of LAEs at $z>6$ does not imply a rapid increase
with redshift of the fraction of the whole IGM volume that is atomic, but is
accounted for by a rapid increase of the neutral fraction in the infall regions
around galaxy host halos.


title: Common Envelope ejection for a Luminous Red Nova in M101

abstract:
  We present the results of optical, near-infrared, and mid-infrared
observations of M101 OT2015-1 (PSN J14021678+5426205), a luminous red transient
in the Pinwheel galaxy (M101), spanning a total of 16 years. The lightcurve
showed two distinct peaks with absolute magnitudes $M_r\leq-12.4$ and $M_r
\simeq-12$, on 2014 November 11 and 2015 February 17, respectively. The
spectral energy distributions during the second maximum show a cool outburst
temperature of $\approx$3700 K and low expansion velocities ($\approx-$300
\kms) for the H I, Ca II, Ba II and K I lines. From archival data spanning 15
to 8 years before the outburst, we find a single source consistent with the
optically discovered transient which we attribute to being the progenitor; it
has properties consistent with being an F-type yellow supergiant with
$L$~$\sim$~8.7~$\times\ 10^4$ \Lsun, $T_{\rm{eff}}\approx$7000~K and an
estimated mass of $\rm{M1}= 18\pm 1$ \Msun. This star has likely just finished
the H burning phase in the core, started expanding, and is now crossing the
Hertzsprung gap. Based on the combination of observed properties, we argue that
the progenitor is a binary system, with the more evolved system overfilling the
Roche lobe. Comparison with binary evolution models suggests that the outburst
was an extremely rare phenomenon, likely associated with the ejection of the
common envelope. The initial mass of the binary progenitor system fills the gap
between the merger candidates V838 Mon (5$-$10 \Msun) and
NGC~4490-OT~(30~\Msun).


title:
Classification of maximally supersymmetric backgrounds in supergravity
  theories

abstract:
  We study maximally supersymmetric solutions of all gauged or deformed
supergravity theories in $D \ge 3$ space-time dimensions. For vanishing
background fluxes the space-time background has to be either Minkowski or
anti-de Sitter. We derive a simple criterion for the existence of solutions
with non-trivial fluxes and determine all supergravities that satisfy it. We
show that their solutions coincide with those of the corresponding ungauged
theories and conclude that the known list of maximally supersymmetric solutions
is exhaustive.


title: Dust traps as planetary birthsites: basics and vortex formation

abstract:
  We present a simple model for low-mass planet formation and subsequent
evolution within "transition" discs. We demonstrate quantitatively that the
predicted and observed structure of such discs are prime birthsites of planets.
Planet formation is likely to proceed through pebble accretion, should a
planetary embryo ($M\gtrsim 10^{-4}\,$M$_\oplus$) form. Efficient pebble
accretion is likely to be unavoidable in transition disc dust traps, as the
size of the dust particles required for pebble accretion are those which are
most efficiently trapped in the transition disc dust trap. Rapid pebble
accretion within the dust trap gives rise, not only to low-mass planets, but to
a large accretion luminosity. This accretion luminosity is sufficient to heat
the disc outside the gravitational influence of the planet and makes the disc
locally baroclinic, and a source of vorticity. Using numerical simulations we
demonstrate that this source of vorticity can lead to the growth of a single
large scale vortex in $\sim 100$ orbits, which is capable of trapping
particles. Finally, we suggest an evolutionary cycle: planet formation proceeds
through pebble accretion, followed by vortex formation and particle trapping in
the vortex quenching the planetary accretion and thus removing the vorticity
source. After the vortex is destroyed the process can begin anew. This means
transition discs should present with large scale vortices for a significant
fraction of their lifetimes and remnant planets at large ~10AU separation
should be a common outcome of this cycle.


title: Matching Matters!

abstract:
  Effective Lagrangians are a useful tool for a data-driven approach to physics
beyond the Standard Model at the LHC. However, for the new physics scales
accessible at the LHC, the effective operator expansion is only relatively
slowly converging at best. For tree-level processes, it has been found that the
agreement between the effective Lagrangian and a range of UV-complete models
depends sensitively on the appropriate definition of the matching. We extend
this analysis to the one-loop level, which is relevant for electroweak
precision data and Higgs decay to photons. We show that near the scale of
electroweak symmetry breaking the validity of the effective theory description
can be systematically improved through an appropriate matching procedure. In
particular, we find a significant increase in accuracy when including suitable
terms suppressed by the Higgs vacuum expectation value in the matching.


title: Limits on Spherical Coefficients in the Minimal-SME Photon Sector

abstract:
  We place limits on spherical coefficients for Lorentz violation involving
operators of dimension four in the photon sector of the minimal Standard-Model
Extension. The bounds are deduced from existing experimental results with
optical-cavity oscillators.


title:
CO-dark gas and molecular filaments in Milky Way-type galaxies - II: The
  temperature distribution of the gas

abstract:
  We investigate the temperature distribution of CO-dark molecular hydrogen
(H2) in a series of disk galaxies simulated using the AREPO moving-mesh code.
In conditions similar to those in the Milky Way, we find that H2 has a flat
temperature distribution ranging from 10 - 100 K. At $T < 30$ K the gas is
almost fully molecular and has a high CO content, whereas at $T > 30$ K, the H2
fraction spans a broader range and the CO content is small, allowing us to
classify gas in these two regimes as CO-bright and CO-dark, respectively. The
mean sound speed in the CO-dark H2 is 0.64 km/s, significantly lower than the
value in the cold atomic gas (1.15 km/s), implying that the CO-dark molecular
phase is more susceptible to turbulent compression and gravitational collapse
than its atomic counterpart. We further show that the temperature of the
CO-dark H2 is highly sensitive to the strength of the interstellar radiation
field, but that conditions in the CO-bright H2 remain largely unchanged.
Finally, we examine the usefulness of the [CII] and [OI] fine structure lines
as tracers of the CO-dark gas. We show that in Milky Way-like conditions,
diffuse [CII] emission from this gas should be detectable. However, it is a
problematic tracer of this gas, as there is only a weak correlation between the
brightness of the emission and the H2 surface density. The situation is even
worse for the [OI] line, which shows no correlation with the H2 surface
density.


title: Stochastic Frank-Wolfe Methods for Nonconvex Optimization

abstract:
  We study Frank-Wolfe methods for nonconvex stochastic and finite-sum
optimization problems. Frank-Wolfe methods (in the convex case) have gained
tremendous recent interest in machine learning and optimization communities due
to their projection-free property and their ability to exploit structured
constraints. However, our understanding of these algorithms in the nonconvex
setting is fairly limited. In this paper, we propose nonconvex stochastic
Frank-Wolfe methods and analyze their convergence properties. For objective
functions that decompose into a finite-sum, we leverage ideas from variance
reduction techniques for convex optimization to obtain new variance reduced
nonconvex Frank-Wolfe methods that have provably faster convergence than the
classical Frank-Wolfe method. Finally, we show that the faster convergence
rates of our variance reduced methods also translate into improved convergence
rates for the stochastic setting.


title: Spatial Models for Field Trials

abstract:
  An important aim of the analysis of agricultural field trials is to obtain
good predictions for genotypic performance, by correcting for spatial effects.
In practice these corrections turn out to be complicated, since there can be
different types of spatial effects; those due to management interventions
applied to the field plots and those due to various kinds of erratic spatial
trends. This paper presents models for field trials in which the random spatial
component consists of tensor product Penalized splines (P-splines). A special
ANOVA-type reformulation leads to five smooth additive spatial components,
which form the basis of a mixed model with five unknown variance components. On
top of this spatial field, effects of genotypes, blocks, replicates, and/or
other sources of spatial variation are described by a mixed model in a standard
way. We show the relation between several definitions of heritability and the
effective dimension or the effective degrees of freedom associated to the
genetic component. The approach is illustrated with large-scale field trial
experiments. An R-package is provided.


title:
A new approach for the strong unique continuation of electromagnetic
  Schroedinger operator with complex-valued coefficient

abstract:
  This paper mainly addresses the strong unique continuation property for the
electromagnetic Schr\"{o}dinger operator with complex-valued coefficients.
Appropriate multipliers with physical backgrounds have been introduced to prove
a priori estimates. Moreover, its application in an exact controllability
problem has been shown, in which case, the boundary value determines the
interior value completely.


title: Optical and radio astrometry of the galaxy associated with FRB150418

abstract:
  A fading radio source, coincident in time and position with the fast radio
burst FRB150418, has been associated with the galaxy WISE J071634.59-190039.2.
Subsequent observations of this galaxy have revealed that it contains a
persistent, but variable, radio source. We present e-MERLIN, VLBA, and ATCA
radio observations and Subaru optical observations of WISE J071634.59-190039.2
and find that the persistent radio source is unresolved and must be compact
(<0.01 kpc), and that its location is consistent with the optical centre of the
galaxy. We conclude that it is likely that WISE J071634.59-190039.2 contains a
weak radio AGN.


title:
Nordhaus-Gaddum and other bounds for the sum of squares of the positive
  eigenvalues of a graph

abstract:
  Terpai [22] proved the Nordhaus-Gaddum bound that $\mu(G) + \mu(\overline{G})
\le 4n/3 - 1$, where $\mu(G)$ is the spectral radius of a graph $G$ with $n$
vertices. Let $s^+$ denote the sum of the squares of the positive eigenvalues
of $G$. We prove that $\sqrt{s^{+}(G)} + \sqrt{s^+(\overline{G})} < \sqrt{2}n$
and conjecture that $\sqrt{s^{+}(G)} + \sqrt{s^+(\overline{G})} \le 4n/3 - 1.$
We have used AutoGraphiX and Wolfram Mathematica to search for a
counter-example. We also consider Nordhaus-Gaddum bounds for $s^+$ and bounds
for the Randi\'c index.


title:
Adaptive Signal Detection and Parameter Estimation in Unknown Colored
  Gaussian Noise

abstract:
  This paper considers the general signal detection and parameter estimation
problem in the presence of colored Gaussian noise disturbance. By modeling the
disturbance with an autoregressive process, we present three signal detectors
with different unknown parameters under the general framework of binary
hypothesis testing. The closed form of parameter estimates and the asymptotic
distributions of these three tests are also given. Given two examples of
frequency modulated signal detection problem and time series moving object
detection problem, the simulation results demonstrate the effectiveness of
three presented detectors.


title: The universal K3 surface of genus 14 via cubic fourfolds

abstract:
  Using the isomorphism between the moduli space of polarized K3 surfaces of
genus 14 and the moduli space of special cubic fourfolds of discriminant 26, we
establish the rationality of the universal K3 surface of genus 14. Precisely,
we show that the universal K3 surface of genus 14 is a projective bundle over a
certain moduli space of nodal scrolls in P^5, whose rationality we prove using
a degenerate version of Mukai's structure theorem for curves of genus 8.


title:
Magnetic Collapse and the Behavior of Transition Metal Oxides at High
  Pressure

abstract:
  We report a detail theoretical study of the electronic structure and phase
stability of transition metal oxides MnO, FeO, CoO, and NiO in their
paramagnetic cubic B1 structure by employing dynamical mean-field theory of
correlated electrons combined with \emph{ab initio} band structure methods
(DFT+DMFT). Our calculations reveal that under pressure these materials exhibit
a Mott insulator-metal transition (IMT) which is accompanied by a simultaneous
collapse of local magnetic moments and lattice volume, implying a complex
interplay between chemical bonding and electronic correlations. Moreover, our
results for the transition pressure show a monotonous decrease from ~ 145 GPa
to 40 GPa, upon moving from MnO to CoO. In contrast to that, in NiO, magnetic
collapse is found to occur at remarkably higher pressure of ~ 429 GPa. We
provide a unified picture of such a behavior and suggest that it is primary a
localized to itinerant moment behavior transition at the IMT that gives rise to
magnetic collapse in transition metal oxides.


title:
On plastikstufe, bordered Legendrian open book and overtwisted contact
  structures

abstract:
  In this paper we prove the presence of an embedded plastikstufe implies
overtwistedness of the contact structure in any dimension. Moreover, we show in
dimension 5 that the presence of an embedded bordered Legendrian open book
(bLob) also implies overtwistedness. Applications of these criteria to certain
(contact) fibered connected sums and open books are discussed.


title: Mesoscale Structure of Chiral Nematic Shells

abstract:
  There is considerable interest in understanding and controlling topological
defects in nematic liquid crystals (LCs). Confinement, in the form of droplets,
has been particularly effective in that regard. Here, we employ the Landau-de
Gennes method to explore the geometrical frustration of nematic order in shell
geometries, and focus on chiral materials. By varying the chirality and
thickness in uniform shells, we construct a phase diagram that includes
tetravalent structures, bipolar structures (BS), bent structures and radial
spherical structures (RSS). It is found that, in uniform shells, the BS-to-RSS
structural transition, in response to both chirality and shell geometry, is
accompanied by an abrupt change of defect positions, implying a potential use
for chiral nematic shells as sensors. Moreover, we investigate thickness
heterogeneity in shells and demonstrate that non-chiral and chiral nematic
shells exhibit distinct equilibrium positions of their inner core that are
governed by shell chirality c.


title: Synthetic Approach to the Singularity Problem

abstract:
  We try to convince the reader that the categorical version of differential
geometry, called Synthetic Differential Geometry (SDG), offers valuable tools
which can be applied to work with some unsolved problems of general relativity.
We do this with respect to the space-time singularity problem. The essential
difference between the usual differential geometry and SDG is that the latter
enriches the real line by introducing infinitesimal of various kinds. Owing to
this geometry acquires a tool to penetrate "infinitesimally small" parts of a
given manifold. However, to make use of this tool we must switch from the
category of sets to some other suitable category. We try two topoi: the topos
${\cal G}$ of germ determined ideals and the so-called Basel topos ${\cal B}$.
The category of manifolds is a subcategory of both of them. In ${\cal G}$, we
construct a simple model of a contracting sphere. As the sphere shrinks, its
curvature increases, but when the radius of the sphere reaches infinitesimal
values, the curvature becomes infinitesimal and the singularity is avoided. The
topos ${\cal B}$, unlike the topos ${\cal G}$, has invertible infinitesimal and
infinitely large nonstandard natural numbers. This allows us to see what
happens when a function "goes through a singularity". When changing from the
category of sets to another topos, one must be ready to switch from classical
logic to intuitionistic logic. This is a radical step, but the logic of the
universe is not obliged to conform to the logic of our brains.


title: A radio pulsing white dwarf binary star

abstract:
  White dwarfs are compact stars, similar in size to Earth but ~200,000 times
more massive. Isolated white dwarfs emit most of their power from ultraviolet
to near-infrared wavelengths, but when in close orbits with less dense stars,
white dwarfs can strip material from their companions, and the resulting mass
transfer can generate atomic line and X-ray emission, as well as near- and
mid-infrared radiation if the white dwarf is magnetic. However, even in
binaries, white dwarfs are rarely detected at far-infrared or radio
frequencies. Here we report the discovery of a white dwarf / cool star binary
that emits from X-ray to radio wavelengths. The star, AR Scorpii (henceforth AR
Sco), was classified in the early 1970s as a delta-Scuti star, a common variety
of periodic variable star. Our observations reveal instead a 3.56 hr period
close binary, pulsing in brightness on a period of 1.97 min. The pulses are so
intense that AR Sco's optical flux can increase by a factor of four within 30
s, and they are detectable at radio frequencies, the first such detection for
any white dwarf system. They reflect the spin of a magnetic white dwarf which
we find to be slowing down on a 10^7 yr timescale. The spin-down power is an
order of magnitude larger than that seen in electromagnetic radiation, which,
together with an absence of obvious signs of accretion, suggests that AR Sco is
primarily spin-powered. Although the pulsations are driven by the white dwarf's
spin, they originate in large part from the cool star. AR Sco's broad-band
spectrum is characteristic of synchrotron radiation, requiring relativistic
electrons. These must either originate from near the white dwarf or be
generated in situ at the M star through direct interaction with the white
dwarf's magnetosphere.


title:
Frequency dispersion of small-amplitude capillary waves in viscous
  fluids

abstract:
  This work presents a detailed study of the dispersion of capillary waves with
small amplitude in viscous fluids using an analytically derived solution to the
initial value problem of a small-amplitude capillary wave as well as direct
numerical simulation. A rational parametrization for the dispersion of
capillary waves in the underdamped regime is proposed, including predictions
for the wavenumber of critical damping based on a harmonic oscillator model.
The scaling resulting from this parametrization leads to a self-similar
solution of the frequency dispersion of capillary waves that covers the entire
underdamped regime, which allows an accurate evaluation of the frequency at a
given wavenumber, irrespective of the fluid properties. This similarity also
reveals characteristic features of capillary waves, for instance that critical
damping occurs when the characteristic timescales of dispersive and dissipative
mechanisms are balanced. In addition, the presented results suggest that the
widely adopted hydrodynamic theory for damped capillary waves does not
accurately predict the dispersion when viscous damping is significant and a new
definition of the damping rate, which provides consistent accuracy in the
underdamped regime, is presented.


title:
Assessment of Predictor-Corrector strategy for the Burridge-Knopoff
  model

abstract:
  A Predictor-Corrector strategy is employed for the numerical simulation of
the one-dimensional Burridge-Knopoff model of earthquakes. This approach is
totally explicit and allows to reproduce the main features of the model. The
results achieved are compared with those of several previous works available in
the literature, in order to state the effectiveness of the novel numerical
strategy. Simulations are performed starting from the simplest cases and are
aimed at studying the qualitative trends of the phenomena under analysis. By
increasing the size of the associated differential system, it is possible to
examine data on the basis of the Gutenberg-Richter statistical law. Finally,
some tests are conducted to investigate the continuum limit of the discrete
Burridge-Knopoff model towards a macroscopic dynamics.


title:
Kinetics of Diffusion-Controlled Annihilation with Sparse Initial
  Conditions

abstract:
  We study diffusion-controlled single-species annihilation with sparse initial
conditions. In this random process, particles undergo Brownian motion, and when
two particles meet, both disappear. We focus on sparse initial conditions where
particles occupy a subspace of dimension $\delta$ that is embedded in a larger
space of dimension $d$. We find that the co-dimension $\Delta=d-\delta$ governs
the behavior. All particles disappear when the co-dimension is sufficiently
small, $\Delta\leq 2$; otherwise, a finite fraction of particles indefinitely
survive. We establish the asymptotic behavior of the probability $S(t)$ that a
test particle survives until time $t$. When the subspace is a line, $\delta=1$,
we find inverse logarithmic decay, $S\sim (\ln t)^{-1}$, in three dimensions,
and a modified power-law decay, $S\sim (\ln t)\,t^{-1/2}$, in two dimensions.
In general, the survival probability decays algebraically when $\Delta <2$, and
there is an inverse logarithmic decay at the critical co-dimension $\Delta=2$.


title:
Computation of asymptotic expansions of turning point problems via
  Cauchy's integral formula: Bessel functions

abstract:
  Linear second order differential equations having a large real parameter and
turning point in the complex plane are considered. Classical asymptotic
expansions for solutions involve the Airy function and its derivative, along
with two infinite series, the coefficients of which are usually difficult to
compute. By considering the series as asymptotic expansions for two explicitly
defined analytic functions, Cauchy's integral formula is employed to compute
the coefficient functions to high order of accuracy. The method employs a
certain exponential form of Liouville-Green expansions for solutions of the
differential equation, as well as for the Airy function. We illustrate the use
of the method with the high accuracy computation of Airy-type expansions of
Bessel functions of complex argument.


title: Approximating certain cell-like maps by homeomorphisms

abstract:
  Given a proper map f : M $\rightarrow$ Q, having cell-like point-inverses,
from a manifold-without-boundary M onto an ANR Q, it is a much-studied problem
to find when f is approximable by homeomorphisms, i.e., when the decomposition
of M induced by f is shrinkable (in the sense of Bing). If dimension M $\geq$
5, J. W. Cannon's recent work focuses attention on whether Q has the disjoint
disc property (which is: Any two maps of a 2-disc into Q can be homotoped by an
arbitrarily small amount to have disjoint images; this is clearly a necessary
condition for Q to be a manifold, in this dimension range). This paper
establishes that such an f is approximable by homeomorphisms whenever dimension
M $\geq$ 5 and Q has the disjoint disc property. As a corollary, one obtains
that given an arbitrary map f : M $\rightarrow$ Q as above, the stabilized map
f $\times$ id($\mathbb{R}^{2}$) : M $\times$ $\mathbb{R}^{2}$ -> Q $\times$
$\mathbb{R}^{2}$ is approximable by homeomorphisms. The proof of the theorem is
different from the proofs of the special cases in the earlier work of myself
and Cannon, and it is quite self-contained. This work provides an alternative
proof of L. Siebenmann's Approximation Theorem, which is the case where Q is
given to be a manifold.


title:
Multi-Tenant Radio Access Network Slicing: Statistical Multiplexing of
  Spatial Loads

abstract:
  This paper addresses the slicing of Radio Access Network (RAN) resources by
multiple tenants, e.g., virtual wireless operators and service providers. We
consider a criterion for dynamic resource allocation amongst tenants, based on
a weighted proportionally fair objective, which achieves desirable
fairness/protection across the network slices of the different tenants and
their associated users. Several key properties are established, including: the
Pareto optimality of user association to base stations, the fair allocation of
base stations resources, and the gains resulting from dynamic resource sharing
across slices, both in terms of utility gains and capacity savings. We then
address algorithmic and practical challenges in realizing the proposed
criterion. We show that the objective is NP-hard, making an exact solution
impractical, and design a distributed semi-online algorithm which meets
performance guarantees in equilibrium and can be shown to quickly converge to a
region around the equilibrium point. Building on this algorithm, we devise a
practical approach with limited computational, information, and handoff
overheads. We use detailed simulations to show that our approach is indeed
near-optimal and provides substantial gains both to tenants (in terms of
capacity savings) and end-users (in terms of improved performance).


title:
Integral points of bounded degree on the projective line and in
  dynamical orbits

abstract:
  Let $D$ be a non-empty effective divisor on $\mathbb{P}^1$. We show that when
ordered by height, any set of $(D,S)$-integral points on $\mathbb{P}^1$ of
bounded degree has relative density zero. We then apply this to arithmetic
dynamics: let $\varphi(z)\in \overline{\mathbb{Q}}(z)$ be a rational function
of degree at least two whose second iterate $\varphi^2(z)$ is not a polynomial.
We show that as we vary over points $P\in\mathbb{P}^1(\overline{\mathbb{Q}})$
of bounded degree, the number of algebraic integers in the forward orbit of $P$
is absolutely bounded and zero on average.


title:
Concolic Unbounded-Thread Reachability via Loop Summaries (Extended
  Technical Report)

abstract:
  We present a method for accelerating explicit-state backward search
algorithms for systems of arbitrarily many finite-state threads. Our method
statically analyzes the program executed by the threads for the existence of
simple loops. We show how such loops can be collapsed without approximation
into Presburger arithmetic constraints that symbolically summarize the effect
of executing the backward search algorithm along the loop in the multi-threaded
program. As a result, the subsequent explicit-state search does not need to
explore the summarized part of the state space. The combination of concrete and
symbolic exploration gives our algorithm a concolic flavor. We demonstrate the
power of this method for proving and refuting safety properties of
unbounded-thread programs.


title:
Bandwidth Selection for Kernel Density Estimation with a Markov Chain
  Monte Carlo Sample

abstract:
  Markov chain Monte Carlo samplers produce dependent streams of variates drawn
from the limiting distribution of the Markov chain. With this as motivation, we
introduce novel univariate kernel density estimators which are appropriate for
the stationary sequences of dependent variates. We modify the asymptotic mean
integrated squared error criterion to account for dependence and find that the
modified criterion suggests data-driven adjustments to standard bandwidth
selection methods. Simulation studies show that our proposed methods find
bandwidths close to the optimal value while standard methods lead to smaller
bandwidths and hence to undersmoothed density estimates. Empirically, the
proposed methods have considerably smaller integrated mean squared error than
do standard methods.


title:
MOCCA-SURVEY Database I: Is NGC 6535 a Dark Star Cluster Harboring an
  IMBH?

abstract:
  We describe the dynamical evolution of a unique type of dark star cluster
model in which the majority of the cluster mass at Hubble time is dominated by
an intermediate-mass black hole (IMBH). We analyzed results from about 2000
star cluster models (Survey Database I) simulated using the Monte-Carlo code
MOCCA and identified these dark star cluster models. Taking one of these
models, we apply the method of simulating realistic "mock observations" by
utilizing the COCOA and SISCO codes to obtain the photometric and kinematic
observational properties of the dark star cluster model at 12 Gyr. We find that
the perplexing Galactic globular cluster NGC 6535 closely matches the
observational photometric and kinematic properties of the dark star cluster
model presented in this paper. Based on our analysis and currently observed
properties of NGC 6535, we suggest that this globular cluster could potentially
harbour an IMBH. If it exists, the presence of this IMBH can be detected
robustly with proposed kinematic observations of NGC 6535.


title: $(\mu, \rho, \beta)$-Extension of $3$-Lie algebras

abstract:
  We study an extension algebra $A$ from two given $3$-Lie algebras $M$ and
$H$, and discuss the extensibility of a pair of derivations, one from the
derivation algebra of $M$ and the other from that of $H$, to a derivation of
$A$. In particular, we give conditions for such an extension to be a $3$-Lie
algebra, and provide necessary and sufficient conditions of the pair of
derivations to be extendable.


title:
Beyond the Dolev-Yao Model: Realistic Application-Specific Attacker
  Models for Applications Using Vehicular Communication

abstract:
  In recent time, the standards for Vehicular Ad-hoc Networks (VANETs) and
Intelligent Transportation Systems (ITSs) matured and scientific and industry
interest is high especially as autonomous driving gets a lot of media
attention. Autonomous driving and other assistance systems for cars make heavy
use of VANETs to exchange information.They may provide more comfort, security
and safety for drivers. However, it is of crucial importance for the user's
trust in these assistance systems that they could not be influenced by
malicious users. VANETs are likely attack vectors for such malicious users,
hence application-specific security requirements must be considered during the
design of applications using VANETs. In literature, many attacks on vehicular
communication have been described but attacks on specific vehicular networking
applications are often missing. This paper fills in this gap by describing
standardized vehicular networking applications, defining and extending previous
attacker models, and using the resulting new models to characterize the
possible attackers interested in the specific vehicular networking application.
The attacker models presented in this paper hopefully provide great benefit for
the scientific community and industry as they allow to compare security
evaluations of different works, characterize attackers, their intentions and
help to plan application-specific security controls for vehicular networking
applications.


title:
Non-Central Limit Theorem for Quadratic Functionals of Hermite-Driven
  Long Memory Moving Average Processes

abstract:
  Let $(Z_t^{(q, H)})_{t \geq 0}$ denote a Hermite process of order $q \geq 1$
and self-similarity parameter $H \in (\frac{1}{2}, 1)$. Consider the
Hermite-driven moving average process $$X_t^{(q, H)} = \int_0^t x(t-u) dZ^{(q,
H)}(u), \qquad t \geq 0.$$ In the special case of $x(u) = e^{-\theta u}, \theta
> 0$, $X$ is the non-stationary Hermite Ornstein-Uhlenbeck process of order
$q$. Under suitable integrability conditions on the kernel $x$, we prove that
as $T \to \infty$, the normalized quadratic functional $$G_T^{(q,
H)}(t)=\frac{1}{T^{2H_0 - 1}}\int_0^{Tt}\Big(\big(X_s^{(q, H)}\big)^2 -
E\Big[\big(X_s^{(q, H)}\big)^2\Big]\Big) ds , \qquad t \geq 0,$$ where $H_0 = 1
+ (H-1)/q$, converges in the sense of finite-dimensional distribution to the
Rosenblatt process of parameter $H' = 1 + (2H-2)/q$, up to a multiplicative
constant, irrespective of self-similarity parameter whenever $q \geq 2$. In the
Gaussian case $(q=1)$, our result complements the study started by Nourdin
\textit{et al} in arXiv:1502.03369, where either central or non-central limit
theorems may arise depending on the value of self-similarity parameter. A
crucial key in our analysis is an extension of the connection between the
classical multiple Wiener-It\^{o} integral and the one with respect to a random
spectral measure (initiated by Taqqu (1979)), which may be independent of
interest.


title: The orbital distribution of trans-Neptunian objects beyond 50 au

abstract:
  The dynamical structure of the Kuiper belt beyond 50 au is not well
understood. Here we report results of a numerical model with long-range, slow
and grainy migration of Neptune. The model implies that bodies scattered
outward by Neptune to semimajor axes a>50 au often evolve into resonances which
subsequently act to raise the perihelion distances of orbits to q>40 au. The
implication of the model is that the orbits with 50<a<100 au and q>40 au should
cluster near (but not in) the resonances with Neptune (3:1 at a=62.6 au, 4:1 at
a=75.9 au, 5:1 at a=88.0 au, etc.). The recent detection of several distant
Kuiper Belt Objects (KBOs) near resonances is consistent with this prediction,
but it is not yet clear whether the orbits are really non-resonant as our model
predicts. We estimate from the model that there should presently be ~1600-2400
bodies at the 3:1 resonance and ~1000-1400 bodies at the 4:1 resonance (for
q>40 au and diameters D>100 km). These results favorably compare with the
population census of distant KBOs inferred from existing observations.


title:
Basis adaptation and domain decomposition for steady partial
  differential equations with random coefficients

abstract:
  We present a novel approach for solving steady-state stochastic partial
differential equations (PDEs) with high-dimensional random parameter space. The
proposed approach combines spatial domain decomposition with basis adaptation
for each subdomain. The basis adaptation is used to address the curse of
dimensionality by constructing an accurate low-dimensional representation of
the stochastic PDE solution (probability density function and/or its leading
statistical moments) in each subdomain. Restricting the basis adaptation to a
specific subdomain affords finding a locally accurate solution. Then, the
solutions from all of the subdomains are stitched together to provide a global
solution. We support our construction with numerical experiments for a
steady-state diffusion equation with a random spatially dependent coefficient.
Our results show that highly accurate global solutions can be obtained with
significantly reduced computational costs.


title: Multi-photon Resonance Phenomena Using Laguerre-Gaussian Beams

abstract:
  We study the influence of laser profile on the linewidth of the optical
spectrum of multi-photon resonance phenomena. First, we investigate the
dependence of the absorption spectrum on the laser profile in a two-level
system. Thanks to the Laguerre-Gaussian field, the linewidth of the one-photon
optical pumping and two-photon absorption peaks are explicitly narrower than
that obtained with a Gaussian field. In next section, it is shown that,
comparing with the the Gaussian fields, the Laguerre-Gaussian ones reduce the
linewidth of the optical spectrum in the coherent population trapping.
Interestingly, it turns out that its use of a Laguerre-Gaussian beam makes the
linewidth of the spectrum narrower as compared with a Gaussian one in a
Doppler-broadened electromagnetically induced transparency. Moreover, we study
the effect of the laser profile on the Autler-Townes doublet structure in the
absorption spectrum for a laser-driven four-level atomic system. We also
consider the different values of the Laguerre-Gaussian mode beam waist, and,
perhaps more remarkable, we find that for the small values of waist, the
Autler-Townes doublet can be removed and a prominent narrow central peak
appears in the absorption spectrum. Finally, we investigate the effect of the
laser profile on the linewidth of the sub-natural three-photon absorption peak
of double dark resonance. The differences in the linewidth are quite large,
offering potential applications in metrology and isotope separation methods.
Our results can be used for super ultra high resolution laser spectroscopy and
to improve the resolution of the technology of isotope/isomer separation and
photo-biology even at essential overlap of the spectra of the different
particles.


title: Grossly Determined Solutions for a Boltzmann-like Equation

abstract:
  In gas dynamics, the connection between the continuum physics model offered
by the Navier-Stokes equations and the heat equation and the molecular model
offered by the kinetic theory of gases has been understood for some time,
especially through the work of Chapman and Enskog, but it has never been
established rigorously. This paper established a precise bridge between this
two models for a simple linear Boltzman-like equation. Specifically a special
class of solutions, the grossly determined solutions, of this kinetic model are
shown to exist and satisfy closed form balance equations representing a class
of continuum model solutions.


title: Exponential sum estimate for systems including linear polynomials

abstract:
  In his paper, W. M. Schmidt obtained an exponential sum estimate for systems
of polynomials not including linear polynomials, which was then used to apply
the Hardy-Littlewood circle method. We prove an analogous estimate for systems
including linear polynomials.


title: A Search for Stellar-Mass Black Holes via Astrometric Microlensing

abstract:
  While dozens of stellar mass black holes have been discovered in binary
systems, isolated black holes have eluded detection. Their presence can be
inferred when they lens light from a background star. We attempt to detect the
astrometric lensing signatures of three photometrically identified microlensing
events, OGLE-2011-BLG-0022, OGLE-2011-BLG-0125, and OGLE-2012-BLG-0169
(OB110022, OB110125, and OB120169), located toward the Galactic Bulge. These
events were selected because of their long durations, which statistically
favors more massive lenses. Astrometric measurements were made over 1-2 years
using laser-guided adaptive optics observations from the W. M. Keck
Observatory. Lens model parameters were first constrained by the photometric
light curves. The OB120169 light curve is well-fit by a single-lens model,
while both OB110022 and OB110125 light curves favor binary-lens models. Using
the photometric fits as prior information, no significant astrometric lensing
signal was detected and all targets were consistent with linear motion. The
significant lack of astrometric signal constrains the lens mass of OB110022 to
0.05-1.79 Msun in a 99.7% confidence interval, which disfavors a black hole
lens. Fits to OB110125 yielded a reduced Einstein crossing time and
insufficient observations during the peak, so no mass limits were obtained. Two
degenerate solutions exist for OB120169, which have a lens mass between
0.2-38.8 Msun and 0.4-39.8 Msun for a 99.7% confidence interval. Follow-up
observations of OB120169 will further constrain the lens mass. Based on our
experience, we use simulations to design optimal astrometric observing
strategies and show that, with more typical observing conditions, detection of
black holes is feasible.


title:
Estimate for Initial MacLaurin Coefficients of Certain Subclasses of
  Bi-univalent Functions of Complex Order Associated with the Hohlov Operator

abstract:
  In this paper we introduce and investigate two new subclasses of the function
class $\Sigma$ of bi-univalent functions of complex order defined in the open
unit disk, which are associated with the Hohlov operator, and satisfying
subordinate conditions. Furthermore, we find estimates on the Taylor-MacLaurin
coefficients $|a_2|$ and $|a_3|$ for functions in these new subclasses. Several
known or new consequences of these results are also pointed out.


title:
Coarsening and clustering in run-and-tumble dynamics with short-range
  exclusion

abstract:
  The emergence of clustering and coarsening in crowded ensembles of
self-propelled agents is studied using a lattice model in one-dimension. The
persistent exclusion process, where particles move at directions that change
randomly at a low tumble rate $\alpha$, is extended allowing sites to be
occupied by more than one particle, with a maximum $n_\text{max}$ per site.
Three phases are distinguished. For $n_\text{max}=1$ a gas of clusters form,
with sizes distributed exponentially and no coarsening takes place. For
$n_\text{max}\geq 3$ and small values of $\alpha$, coarsening takes place and
few large clusters appear, with a large fraction of the total number of
particles in them. In the same range of $n_\text{max}$ but for larger values of
$\alpha$, a gas phase where a negligible fraction of particles takes part of
clusters. Finally, $n_\text{max}=2$ corresponds to a crossover phase. The
character of the transitions between phases is studied extending the model to
allow $n_\text{max}$ to take real values and jumps to an occupied site are
probabilistic. The transition from the gas of clusters to the coarsening phase
is continuous and the mass of the large clusters grows continuously when
varying the maximum occupancy, and the crossover found corresponds to values
close to the transition. The second transition, from the coarsening to the
gaseous phase can be either continuous or discontinuous depending on the
parameters, with a critical point separating both cases.


title: The effect of heterogeneity on flocking behavior and systemic risk

abstract:
  The goal of this paper is to study organized flocking behavior and systemic
risk in heterogeneous mean-field interacting diffusions. We illustrate in a
number of case studies the effect of heterogeneity in the behavior of systemic
risk in the system, i.e., the risk that several agents default simultaneously
as a result of interconnections. We also investigate the effect of
heterogeneity on the "flocking behavior" of different agents, i.e., when agents
with different dynamics end up following very similar paths and follow closely
the mean behavior of the system. Using Laplace asymptotics, we derive an
asymptotic formula for the tail of the loss distribution as the number of
agents grows to infinity. This characterizes the tail of the loss distribution
and the effect of the heterogeneity of the network on the tail loss
probability.


title: Confidence sets for phylogenetic trees

abstract:
  Inferring evolutionary histories (phylogenetic trees) has important
applications in biology, criminology and public health. However, phylogenetic
trees are complex mathematical objects that reside in a non-Euclidean space,
which complicates their analysis. While our mathematical, algorithmic, and
probabilistic understanding of phylogenies in their metric space is mature,
rigorous inferential infrastructure is as yet undeveloped. In this manuscript
we unify recent computational and probabilistic advances to construct
tree--valued confidence sets. The procedure accounts for both centre and
multiple directions of tree--valued variability. We draw on block replicates to
improve testing, identifying the best supported most recent ancestor of the
Zika virus, and formally testing the hypothesis that a Floridian dentist with
AIDS infected two of his patients with HIV. The method illustrates connections
between variability in Euclidean and tree space, opening phylogenetic tree
analysis to techniques available in the multivariate Euclidean setting.


title: Mammalian Value Systems

abstract:
  Characterizing human values is a topic deeply interwoven with the sciences,
humanities, art, and many other human endeavors. In recent years, a number of
thinkers have argued that accelerating trends in computer science, cognitive
science, and related disciplines foreshadow the creation of intelligent
machines which meet and ultimately surpass the cognitive abilities of human
beings, thereby entangling an understanding of human values with future
technological development. Contemporary research accomplishments suggest
sophisticated AI systems becoming widespread and responsible for managing many
aspects of the modern world, from preemptively planning users' travel schedules
and logistics, to fully autonomous vehicles, to domestic robots assisting in
daily living. The extrapolation of these trends has been most forcefully
described in the context of a hypothetical "intelligence explosion," in which
the capabilities of an intelligent software agent would rapidly increase due to
the presence of feedback loops unavailable to biological organisms. The
possibility of superintelligent agents, or simply the widespread deployment of
sophisticated, autonomous AI systems, highlights an important theoretical
problem: the need to separate the cognitive and rational capacities of an agent
from the fundamental goal structure, or value system, which constrains and
guides the agent's actions. The "value alignment problem" is to specify a goal
structure for autonomous agents compatible with human values. In this brief
article, we suggest that recent ideas from affective neuroscience and related
disciplines aimed at characterizing neurological and behavioral universals in
the mammalian class provide important conceptual foundations relevant to
describing human values. We argue that the notion of "mammalian value systems"
points to a potential avenue for fundamental research in AI safety and AI
ethics.


title:
Two-Dimensional Boron Oxides with Dirac Loop and Strongly anisotropic
  Carrier Mobility

abstract:
  Recently, two-dimensional boron sheets have attracted a lot of attentions
owing to their structural polymorphs and outstanding properties. And, due to
chemical complexity and electron deficiency of B atoms, the 2D boron sheets are
easy affected by the environment. So, exploring novel 2D boron oxides gets
highly needed. In this study, we theoretically explored 2D boron oxides
structures and their basic properties. We found 2D boron oxides are metals or
semimetals, when oxygen concentration is low. More interesting, the B6O1
exhibits Dirac Loop near the Fermi level and the maximum Fermi velocity is
estimated as high as 0.61*10E6 m/s, which much close to that in graphene. In
addition, when the oxygen concentration is one forth, the most stable B4O1 get
a semiconductor with a direct band gap of 1.24 eV and a strong anisotropic
carrier mobility. Such huge differences of carrier mobility between two
directions have not been reported in other 2D materials. Besides, when oxygen
concentra-tion is higher than one forth, the 2D boron sheets will get unstable
based our results. We also proposed a method how to synthesize these systems.
Our work provide a basic knowledge of 2D boron oxides and may lead to novel 2D
boron oxides discovered. The unique electronic properties of the B6O1 and B4O1
render them promising 2D materials for applications in high-performance
nanodevices.


title:
The first few unicyclic and bicyclic hypergraphs with larger spectral
  radii

abstract:
  A connected $k$-uniform hypergraph with $n$ vertices and $m$ edges is called
$r$-cyclic if $n=m(k-1)-r+1$. For $r=1$ or $2$, the hypergraph is simply called
unicyclic or bicyclic. In this paper we investigate hypergraphs that attain
larger spectral radii among all simple connected $k$-uniform unicyclic and
bicyclic hypergraphs. Specifically, by using some edge operations, the formula
on power hypergraph eigenvalues, the weighted incidence matrix and a result on
linear unicyclic hypergraphs, we determined the first five hypergraphs with
larger spectral radius among all unicyclic hypergraphs and the first three over
all bicyclic hypergraphs.


title:
Comments on "Approximate Characterizations for the Gaussian Source
  Broadcast Distortion Region"

abstract:
  Recently, Tian et al. [1] considered joint source-channel coding of
transmitting a Gaussian source over $K$-user Gaussian broadcast channel, and
derived an outer bound on the admissible distortion region. In [1], they stated
"due to its nonlinear form, it appears difficult to determine whether it is
always looser than the trivial outer bound in all distortion regimes with
bandwidth compression". However, in this correspondence we solve this problem
and prove that for the bandwidth expansion case ($K\geq2$), this outer bound is
strictly tighter than the trivial outer bound with each user being optimal in
the point-to-point setting; while for the bandwidth compression or bandwidth
match case, this outer bound actually degenerates to the trivial outer bound.
Therefore, our results imply that on one hand, the outer bound given in [1] is
nontrivial only for Gaussian broadcast communication ($K\geq2$) with bandwidth
expansion; on the other hand, unfortunately, no nontrivial outer bound exists
so far for Gaussian broadcast communication ($K\geq2$) with bandwidth
compression.


title: Sulfur and few-layer graphene interaction under thermal treatments

abstract:
  In this work we study sulfur confined between two multilayer graphene films
under thermal treatments by means of electrical and Raman spectroscopy
characterization. We found some similarities between the electrical behavior
and differential scanning calorimetry of sulfur immersed into nanoporous anodic
alumina template during sulfur phase transitions, this suggests that sulfur has
a different thermal behavior when it is in confining conditions compared to the
free state. In addition, multilayer graphene was exposed to sulfur vapors at
500 {\deg}C to induce chemical reaction. This method effectively produced
covalent bonding between sulfur and multilayer graphene and a p-type doping of
about 2x10^13 cm^-2 in charge concentration. Finally, based on first principle
calculations we speculate on the existence of a new bidimensional structure of
sulfur.


title: A Universal Genus-Two Curve from Siegel Modular Forms

abstract:
  Let $\mathfrak p$ be any point in the moduli space of genus-two curves
$\mathcal M_2$ and $K$ its field of moduli. We provide a universal equation of
a genus-two curve $\mathcal C_{\alpha, \beta}$ defined over $K(\alpha, \beta)$,
corresponding to $\mathfrak p$, where $\alpha $ and $\beta$ satisfy a quadratic
$\alpha^2+ b \beta^2= c$ such that $b$ and $c$ are given in terms of ratios of
Siegel modular forms. The curve $\mathcal C_{\alpha, \beta}$ is defined over
the field of moduli $K$ if and only if the quadratic has a $K$-rational point
$(\alpha, \beta)$. We discover some interesting symmetries of the Weierstrass
equation of $\mathcal C_{\alpha, \beta}$. This extends previous work of Mestre
and others.


title:
Convergence of the solutions of the discounted equation: the discrete
  case

abstract:
  We derive a discrete version of the results of our previous work. If $M$ is a
compact metric space, $c : M\times M \to \mathbb R$ a continuous cost function
and $\lambda \in (0,1)$, the unique solution to the discrete
$\lambda$-discounted equation is the only function $u_\lambda : M\to \mathbb R$
such that $$\forall x\in M, \quad u_\lambda(x) = \min_{y\in M} \lambda
u_\lambda (y) + c(y,x).$$ We prove that there exists a unique constant
$\alpha\in \mathbb R$ such that the family of $u_\lambda+\alpha/(1-\lambda)$ is
bounded as $\lambda \to 1$ and that for this $\alpha$, the family uniformly
converges to a function $u_0 : M\to \mathbb R$ which then verifies $$\forall
x\in X, \quad u_0(x) = \min_{y\in X}u_0(y) + c(y,x)+\alpha.$$ The proofs make
use of Discrete Weak KAM theory. We also characterize $u_0$ in terms of Peierls
barrier and projected Mather measures.


title: Emergent fuzzy geometry and fuzzy physics in $4$ dimensions

abstract:
  A detailed Monte Carlo calculation of the phase diagram of bosonic IKKT
Yang-Mills matrix models in three and six dimensions with quartic mass
deformations is given. Background emergent fuzzy geometries in two and four
dimensions are observed with a fluctuation given by a noncommutative $U(1)$
gauge theory very weakly coupled to normal scalar fields. The geometry, which
is determined dynamically, is given by the fuzzy spheres ${\bf S}^2_N$ and
${\bf S}^2_N\times{\bf S}^2_N$ respectively. The three and six matrix models
are in the same universality class with some differences. For example, in two
dimensions the geometry is completely stable, whereas in four dimensions the
geometry is stable only in the limit $M\longrightarrow \infty$, where $M$ is
the mass of the normal fluctuations. The behavior of the eigenvalue
distribution in the two theories is also different. We also sketch how we can
obtain a stable fuzzy four-sphere ${\bf S}^2_N\times{\bf S}^2_N$ in the large
$N$ limit for all values of $M$ as well as models of topology change in which
the transition between spheres of different dimensions is observed. The stable
fuzzy spheres in two and four dimensions act precisely as regulators which is
the original goal of fuzzy geometry and fuzzy physics. Fuzzy physics and fuzzy
field theory on these spaces are briefly discussed.


title:
The Sum Rate of Vector Gaussian Multiple Description Coding with
  Tree-Structured Covariance Distortion Constraints

abstract:
  A single-letter lower bound on the sum rate of multiple description coding
with tree-structured distortion constraints is established by generalizing
Ozarow's celebrated converse argument through the introduction of auxiliary
random variables that form a Markov tree. For the quadratic vector Gaussian
case, this lower bound is shown to be achievable by an extended version of the
El Gamal-Cover scheme, yielding a complete sum-rate characterization.


title:
Tunneling magnetoresistance in trilayer structures composed of group-IV
  ferromagnetic semiconductor Ge1-xFex, MgO, and Fe

abstract:
  Group-IV-based ferromagnetic semiconductor Ge1-xFex (GeFe) is one of the most
promising materials for efficient spin injectors and detectors for Si and Ge.
Recent first principles calculations (Sakamoto et al., Ref. 9) suggested that
the Fermi level is located in two overlapping largely spin-polarized bands
formed in the bandgap of GeFe; spin-down d(e) band and spin-up p-d(t2) band.
Thus, it is important to clarify how these bands contribute to spin injection
and detection. In this study, we show the first successful observation of the
tunneling magnetoresistance (TMR) in magnetic tunnel junctions (MTJs)
containing a group-IV ferromagnetic semiconductor, that is, in MTJs composed of
epitaxially grown Fe/MgO/Ge0.935Fe0.065. We find that the p-d(t2) band in GeFe
is mainly responsible for the tunneling transport. Although the obtained TMR
ratio is small (0.3%), the TMR ratio is expected to be enhanced by suppressing
leak current through amorphous-like crystal domains observed in MgO.


title: Non-Markovian random walks with memory lapses

abstract:
  We propose an approach to construct Bernoulli trials $\{X_i, i\ge 1\}$
combining dependence and independence periods, and call it Bernoulli sequence
with random dependence (BSRD). The structure of dependence, on the past $S_i =
X_1 + \ldots + X_i$, {defines} a class of non-Markovian random walks of recent
interest in the literature. In this paper, the dependence is activated by an
auxiliary collection of Bernoulli trials $\{Y_i, i\ge 1\}$, called {\it memory
switch sequence}. We introduce the concept of {\it memory lapses property},
which {is} characterized by intervals of consecutive independent steps in BSRD.
The main results include classical limit theorems for a class of linear BSRD.
In particular, we obtain a central limit theorem for a class of BSRD which
generalizes some previous results in literature. Along the paper, several
examples of potential applications are provided.


title:
Nonlinear viscoelasticity and generalized failure criterion for polymer
  gels

abstract:
  Polymer gels behave as soft viscoelastic solids and exhibit a generic
nonlinear mechanical response characterized by pronounced stiffening prior to
irreversible failure, most often through macroscopic fractures. Here, we aim at
capturing the latter scenario for a protein gel using a nonlinear integral
constitutive equation built upon ($i$) the linear viscoelastic response of the
gel, here well described by a power-law relaxation modulus, and ($ii$) the
nonlinear viscoelastic properties of the gel, encoded into a "damping
function". Such formalism predicts quantitatively the gel mechanical response
to a shear start-up experiment, up to the onset of macroscopic failure.
Moreover, as the gel failure involves the irreversible growth of macroscopic
cracks, we couple the latter stress response with Bailey's durability criterion
for brittle solids in order to predict the critical values of the stress
$\sigma_c$ and strain $\gamma_c$ at the failure point, and how they scale with
the applied shear rate. The excellent agreement between theory and experiments
suggests that the crack growth in this soft viscoelastic gel is a Markovian
process, and that Baileys' criterion extends well beyond hard materials such as
metals, glasses, or minerals.