title:
Comparison of Diversity of Type IIb Supernovae with Asymmetry in
  Cassiopeia A Using Light Echoes

abstract:
  We compare the diversity of spectral line velocities in a large sample of
type IIb supernovae (SNe IIb) with the expected asphericity in the explosion,
as measured from the light echoes of Cassiopeia A (Cas A), which was a
historical galactic SN IIb. We revisit the results of Rest et al. (2011a), who
used light echoes to observe Cas A from multiple lines of sight and hence
determine its asphericity, as seen in the velocity of three spectral lines (He
I $\lambda$5876, H$\alpha$ and the Ca II NIR triplet). We confirm and improve
on this measurement by reproducing the effect of the light echoes in the
spectra of several extragalactic SNe IIb found in the literature as well as
mean SN IIb spectra recently created by Liu et al. (2016), and comparing these
to the observed light echo spectra of Cas A, including their associated
uncertainties. In order to quantify the accuracy of this comparison we smooth
the light echo spectra of Cas A using Gaussian processes and use a Monte Carlo
method to measure the absorption velocities of these three features in the
spectra. We then test the hypothesis that the diversity of ejecta velocities
seen in SNe IIb can be explained by asphericity. We do this by comparing the
range of velocities seen in the different light echoes, and hence different
lines of sight, of Cas A to that seen in the population of SNe IIb. We conclude
that these two ranges are of the same order and thus asphericity could be
enough to explain the diversity in the expansion velocity alone.


title:
Disentangling AGN and Star Formation Activity at High Redshift Using
  Hubble Space Telescope Grism Spectroscopy

abstract:
  Differentiating between active galactic nuclei (AGN) activity and star
formation in z ~ 2 galaxies is difficult because traditional methods, such as
line ratio diagnostics, change with redshift while multi-wavelength methods
(X-ray, radio, IR) are sensitive to only the brightest AGN. We have developed a
new method for spatially resolving emission lines in HST/WFC3 G141 grism
spectra and quantifying AGN activity through the spatial gradient of the [O
III]/H$\beta$ line ratio. Through detailed simulations, we show that our novel
line-ratio gradient approach identifies ~ sim 40% more low-mass and obscured
AGN than obtained by classical methods. Based on our simulations, we developed
a relationship that maps stellar mass, star formation rate, and measured [O
III]/H$\beta$ gradient to AGN Eddington ratio. We apply our technique to
previously studied stacked samples of galaxies at z ~2 and find that our
results are consistent with these studies. Using this gradient method will also
be able to inform other galaxy evolution science, such as inside-out quenching
and metallicity gradients, and will be widely applicable to future spatially
resolved JWST data.


title: Regular and positive noncommutative rational functions

abstract:
  Call a noncommutative rational function $r$ regular if it has no
singularities, i.e., $r(X)$ is defined for all tuples of self-adjoint matrices
$X$. In this article regular noncommutative rational functions $r$ are
characterized via the properties of their (minimal size) linear systems
realizations $r=c^* L^{-1}b$. It is shown that $r$ is regular if and only if
$L=A_0+\sum_jA_j x_j$ is privileged. Roughly speaking, a linear pencil $L$ is
privileged if, after a finite sequence of basis changes and restrictions, the
real part of $A_0$ is positive definite and the other $A_j$ are skew-adjoint.
The second main result is a solution to a noncommutative version of Hilbert's
17th problem: a positive regular noncommutative rational function is a sum of
squares.


title:
Theoretical approach to direct resonant inelastic x-ray scattering on
  magnets and superconductors

abstract:
  The capability to probe the dispersion of elementary spin, charge, orbital,
and lattice excitations has positioned resonant inelastic x-ray scattering
(RIXS) at the forefront of photon science. In this work, we will investigate
how RIXS can contribute to a deeper understanding of the orbital properties and
of the pairing mechanism in unconventional high-temperature superconductors. In
particular, we will show how direct RIXS spectra of magnetic excitations can
reveal long-range orbital correlations in transition metal compounds, by
discriminating different kind of orbital order in magnetic and
antiferromagnetic systems. Moreover, we will show how RIXS spectra of
quasiparticle excitations in superconductors can measure the superconducting
gap magnitude, and reveal the presence of nodal points and phase differences of
the superconducting order parameter on the Fermi surface. This can reveal the
properties of the underlying pairing mechanism in unconventional
superconductors, in particular cuprates and iron pnictides, discriminating
between different superconducting order parameter symmetries, such as $s$, $d$
(singlet pairing) and $p$ wave (triplet pairing).


title: SusHi Bento: Beyond NNLO and the heavy-top limit

abstract:
  Version 1.6.0 of the code SusHi is presented. Concerning inclusive CP-even
Higgs production in gluon fusion, the following new features with respect to
previous versions have been implemented: expansion of the partonic cross
section in the soft limit, i.e. around $x=M_H^2/\hat{s}\to 1$; N$^3$LO QCD
corrections in terms of the soft expansion; top-quark mass suppressed terms
through NNLO; matching to the cross section at $x\to 0$ through N$^3$LO. For
CP-even and -odd scalars, an efficient evaluation of the renormalization-scale
dependence is included, and effects of dimension-5 operators can be studied,
which we demonstrate for the SM Higgs boson and for a CP-even scalar with a
mass of $750$ GeV. In addition, as a generalization of the previously available
$b\bar{b}\to H$ cross section, SusHi 1.6.0 provides the cross section for
charged and neutral Higgs production in the annihilation of arbitrary heavy
quarks. At fixed order in perturbation theory, SusHi thus allows to obtain
Higgs cross-section predictions in different models to the highest precision
known today. For the SM Higgs boson of $M_H=125$ GeV, SusHi yields $48.28$ pb
for the gluon-fusion cross section at the LHC at $13$ TeV. Simultaneously,
SusHi provides the renormalization-scale uncertainty of $\pm 1.97$ pb.


title:
Globular Cluster Scale Sizes in Giant Galaxies: Orbital Anisotropy and
  Tidally Under-filling Clusters in M87, NGC 1399, and NGC 5128

abstract:
  We investigate the shallow increase in globular cluster half-light radii with
projected galactocentric distance $R_{gc}$ observed in the giant galaxies M87,
NGC 1399, and NGC 5128. To model the trend in each galaxy, we explore the
effects of orbital anisotropy and tidally under-filling clusters. While a
strong degeneracy exists between the two parameters, we use kinematic studies
to help constrain the distance $R_\beta$ beyond which cluster orbits become
anisotropic, as well as the distance $R_{f\alpha}$ beyond which clusters are
tidally under-filling. For M87 we find $R_\beta > 27$ kpc and $20 < R_{f\alpha}
< 40$ kpc and for NGC 1399 $R_\beta > 13$ kpc and $10 < R_{f\alpha} < 30$ kpc.
The connection of $R_{f\alpha}$ with each galaxy's mass profile indicates the
relationship between size and $R_{gc}$ may be imposed at formation, with only
inner clusters being tidally affected. The best fitted models suggest the
dynamical histories of brightest cluster galaxies yield similar present-day
distributions of cluster properties. For NGC 5128, the central giant in a small
galaxy group, we find $R_\beta > 5$ kpc and $R_{f\alpha} > 30$ kpc. While we
cannot rule out a dependence on $R_{gc}$, NGC 5128 is well fitted by a tidally
filling cluster population with an isotropic distribution of orbits, suggesting
it may have formed via an initial fast accretion phase. Perturbations from the
surrounding environment may also affect a galaxy's orbital anisotropy profile,
as outer clusters in M87 and NGC 1399 have primarily radial orbits while outer
NGC 5128 clusters remain isotropic.


title: The velocity field in MOND cosmology

abstract:
  The recently developed code for N-body/hydrodynamics simulations in Modified
Newtonian Dynamics (MOND), known as RAyMOND, is used to investigate the
consequences of MOND on structure formation in a cosmological context, with a
particular focus on the velocity field. This preliminary study investigates the
results obtained with the two formulations of MOND implemented in RAyMOND, as
well as considering the effects of changing the choice of MOND interpolation
function, and the cosmological evolution of the MOND acceleration scale. The
simulations are contrived such that structure forms in a background cosmology
that is similar to $\Lambda$CDM, but with a significantly lower matter content.
Given this, and the fact that a fully consistent MOND cosmology is still
lacking, we compare our results with a standard $\Lambda$CDM simulation, rather
than observations. As well as demonstrating the effectiveness of using RAyMOND
for cosmological simulations, it is shown that a significant enhancement of the
velocity field is likely an unavoidable consequence of the gravitational
modification implemented in MOND, and may represent a clear observational
signature of such a modification. It is further suggested that such a signal
may be clearest in intermediate density regions such as cluster outskirts and
filaments.


title:
Extensive X-ray variability studies of NGC 7314 using long XMM-Newton
  observations

abstract:
  We present a detailed X-ray variability study of the low mass Active Galactic
Nuclei (AGN) NGC 7314 using the two newly obtained XMM-Newton observations
($140$ and $130$ ks), together with two archival data sets of shorter duration
($45$ and $84$ ks). The relationship between the X-ray variability
characteristics and other physical source properties (such as the black hole
mass) are still relatively poorly defined, especially for low-mass AGN. We
perform a new, fully analytical, power spectral density (PSD) model analysis
method, which will be described in detail in a forthcoming paper, that takes
into consideration the spectral distortions, caused by red-noise leak. We find
that the PSD in the $0.5-10$ keV energy range, can be represented by a bending
power-law with a bend around $6.7\times10^{-5}$ Hz, having a slope of $0.51$
and $1.99$ below and above the bend, respectively. Adding our bend time-scale
estimate, to an already published ensemble of estimates from several AGN,
supports the idea that the bend time-scale depends linearly only on the black
hole mass and not on the bolometric luminosity. Moreover, we find that as the
energy range increases, the PSD normalization increases and there is a hint
that simultaneously the high frequency slope becomes steeper. Finally, the
X-ray time-lag spectrum of NGC 7314 shows some very weak signatures of
relativistic reflection, and the energy resolved time-lag spectrum, for
frequencies around $3\times10^{-4}$ Hz, shows no signatures of X-ray
reverberation. We show that the previous claim about ks time-delays in this
source, is simply an artefact induced by the minuscule number of points
entering during the time-lag estimation in the low frequency part of the
time-lag spectrum (i.e. below $10^{-4}$ Hz).


title:
A giant Ly$\alpha$ nebula in the core of an X-ray cluster at $z=1.99$:
  implications for early energy injection

abstract:
  We present the discovery of a giant $\gtrsim$100~kpc Ly$\alpha$ nebula
detected in the core of the X-ray emitting cluster CL~J1449+0856 at $z=1.99$
through Keck/LRIS narrow-band imaging. This detection extends the known
relation between Ly$\alpha$ nebulae and overdense regions of the Universe to
the dense core of a $5-7\times10^{13}$ M$_{\odot}$ cluster. The most plausible
candidates to power the nebula are two Chandra-detected AGN host cluster
members, while cooling from the X-ray phase and cosmological cold flows are
disfavored primarily because of the high Ly$\alpha$ to X-ray luminosity ratio
($L_{\mathrm{Ly\alpha}}/L_{\mathrm{X}} \approx0.3$, $\gtrsim10-1000\times$
higher than in local cool-core clusters) and by current modeling. Given the
physical conditions of the Ly$\alpha$-emitting gas and the possible interplay
with the X-ray phase, we argue that the Ly$\alpha$ nebula would be short-lived
($\lesssim10$ Myr) if not continuously replenished with cold gas at a rate of
$\gtrsim1000$ M$_{\odot}$ yr$^{-1}$. We investigate the possibility that
cluster galaxies supply the required gas through outflows and we show that
their total mass outflow rate matches the replenishment necessary to sustain
the nebula. This scenario directly implies the extraction of energy from
galaxies and its deposition in the surrounding intracluster medium, as required
to explain the thermodynamic properties of local clusters. We estimate an
energy injection of the order of $\thickapprox2$ keV per particle in the
intracluster medium over a $2$ Gyr interval. In our baseline calculation AGN
provide up to $85$% of the injected energy and 2/3 of the mass, while the rest
is supplied by supernovae-driven winds.


title: Fourier-space combination of Planck and Herschel images

abstract:
  Herschel has revolutionized our ability to measure column densities (N$_{\rm
H}$) and temperatures (T) of molecular clouds thanks to its far infrared
multiwavelength coverage. However, the lack of a well defined background
intensity level in the Herschel data limits the accuracy of the N$_{\rm H}$ and
T maps. We provide a method that corrects the missing Herschel background
intensity levels using the Planck model for foreground Galactic thermal dust
emission. We present a Fourier method that combines the publicly available
Planck model on large angular scales with the Herschel images on smaller
angular scales. We apply our method to two regions spanning a range of Galactic
environments: Perseus and the Galactic plane region around $l = 11\deg$
(HiGal--11). We post-process the combined dust continuum emission images to
generate column density and temperature maps. We compare these to previously
adopted constant--offset corrections. We find significant differences
($\gtrsim$20\%) over significant ($\sim$15\%) areas of the maps, at low column
densities ($N_{\rm H}\lesssim10^{22}$\,cm$^{-2}$) and relatively high
temperatures ($T\gtrsim20$\,K). We also apply our method to synthetic
observations of a simulated molecular cloud to validate our method. Our method
successfully corrects the Herschel images, including both the constant--offset
intensity level and the scale-dependent background variations measured by
Planck. Our method improves the previous constant--offset corrections, which
did not account for variations in the background emission levels.


title:
Powerful Activity in the Bright Ages. I. A Visible/IR Survey of High
  Redshift 3C Radio Galaxies and Quasars

abstract:
  We present new rest frame UV and visible observations of 22 high-redshift (1
< z < 2.5) 3C radio galaxies and QSOs obtained with the Hubble Space
Telescope's (HST) Wide Field Camera 3 (WFC3) instrument. Using a custom data
reduction strategy in order to assure the removal of cosmic rays, persistence
signal, and other data artifacts, we have produced high-quality science-ready
images of the targets and their local environments. We observe targets with
regions of UV emission suggestive of active star formation. In addition,
several targets exhibit highly distorted host galaxy morphologies in the rest
frame visible images. Photometric analyses reveals that brighter QSOs tend to
be generally redder than their dimmer counterparts. Using emission line fluxes
from the literature, we estimate that emission line contamination is relatively
small in the rest frame UV images for the QSOs. Using archival VLA data, we
have also created radio map overlays for each of our targets, allowing for
analysis of the optical and radio axes alignment.


title:
Quantum ground state control in superconductor-silicene structures:
  $0$-$\pi$ transitions, $\varphi_0$-junctions, and Majorana bound states

abstract:
  We demonstrate theoretically that proximity-induced superconductivity in
silicene offers the possibility to exert strong quantum ground state control.
We show that electrically controlled $0$-$\pi$ transitions occur in Josephson
junctions in the presence of an exchange field due to the buckling of the
silicene lattice. We also discover that zigzag-oriented interfaces, featuring
intervalley scattering, cause a $\varphi_0$ state with an applied electric
field. Finally, we demonstrate that Majorana bound states along the silicene
edge are tunable via the edge orientation, electric, and in-plane spin exchange
fields.


title: Generic Superweak Chaos Induced by Hall Effect

abstract:
  We introduce and study the "kicked Hall system" (KHS), i.e., charged
particles periodically kicked in the presence of uniform magnetic
($\mathbf{B}$) and electric ($\mathbf{E}$) fields that are perpendicular to
each other and to the kicking direction. We show that for resonant values of
$B$ and $E$ and in the weak-chaos regime of sufficiently small nonintegrability
parameter $\kappa$ (the kicking strength), there exists a \emph{generic} family
of periodic kicking potentials for which the Hall effect from $\mathbf{B}$ and
$\mathbf{E}$ significantly suppresses the weak chaos, replacing it by
\emph{"superweak"} chaos (SWC). This means that the system behaves as if the
kicking strength were $\kappa ^2$ rather than $\kappa$. For $E=0$, SWC is known
to be a classical fingerprint of quantum antiresonance but it occurs under much
less generic conditions, in particular only for very special kicking
potentials. Manifestations of SWC are a decrease in the instability of periodic
orbits and a narrowing of the chaotic layers, relative to the ordinary
weak-chaos case. Also, for global SWC, taking place on an infinite "stochastic
web" in phase space, the chaotic diffusion on the web is much slower than the
weak-chaos one. Thus, the Hall effect can be relatively stabilizing for small
$\kappa$. In some special cases, the effect is shown to cause ballistic motion
for almost all parameter values. The generic global SWC on stochastic webs in
the KHS appears to be the two-dimensional closest analog to the Arnol'd web in
higher dimensional systems.


title:
Charged Particles Multiplicity and Scaling Violation of Fragmentation
  Functions in Electron-Positron Annihilation

abstract:
  In electron positron annihilation, changing quarks into the final hadron
states is being described by fragmentation function. Based on the scaling
hypothesis, this function will be independent from the center of mass energy.
Gluon radiation violates the scaling feature. Transverse momentum distribution
plays an important role in scaling violation of fragmentation functions. In
this article, by the use of data resulted from the annihilation process of
electron positron in AMY detector at 60 GeV center of mass energy, first,
charged particles multiplicity distribution will be obtained and it will be
fitted with the KNO scaling. Furthermore, momentum spectra of charged particles
and momentum distribution respect to the jet axis will be obtained. Then, the
results will be compared regarding the different models of QCD; as well, the
distribution of fragmentation functions and scaling violations will be studied.
It is being expected that the scaling violations of the fragmentation functions
of gluon jet are stronger to the quark one. One of the reasons for such case is
that splitting function of jet is larger than splitting function of gluon.


title: Lie theory of vector bundles, Poisson geometry and double structures

abstract:
  We briefly review our results on the Lie theory underlying vector bundles
over Lie groupoids and Lie algebroids, pointing out the role of Poisson
geometry in extending these results to double Lie algebroids and LA-groupoids.


title: Stellar classification from single-band imaging using machine learning

abstract:
  Information on the spectral types of stars is of great interest in view of
the exploitation of space-based imaging surveys. In this article, we
investigate the classification of stars into spectral types using only the
shape of their diffraction pattern in a single broad-band image. We propose a
supervised machine learning approach to this endeavour, based on principal
component analysis (PCA) for dimensionality reduction, followed by artificial
neural networks (ANNs) estimating the spectral type. Our analysis is performed
with image simulations mimicking the Hubble Space Telescope (HST) Advanced
Camera for Surveys (ACS) in the F606W and F814W bands, as well as the Euclid
VIS imager. We first demonstrate this classification in a simple context,
assuming perfect knowledge of the point spread function (PSF) model and the
possibility of accurately generating mock training data for the machine
learning. We then analyse its performance in a fully data-driven situation, in
which the training would be performed with a limited subset of bright stars
from a survey, and an unknown PSF with spatial variations across the detector.
We use simulations of main-sequence stars with flat distributions in spectral
type and in signal-to-noise ratio, and classify these stars into 13 spectral
subclasses, from O5 to M5. Under these conditions, the algorithm achieves a
high success rate both for Euclid and HST images, with typical errors of half a
spectral class. Although more detailed simulations would be needed to assess
the performance of the algorithm on a specific survey, this shows that stellar
classification from single-band images is well possible.


title: Theta bases are atomic

abstract:
  Fock and Goncharov conjectured that the indecomposable universally positive
(i.e., atomic) elements of a cluster algebra should form a basis for the
algebra. This was shown to be false by Lee-Li-Zelevinsky. However, we find that
the theta bases of Gross-Hacking-Keel-Kontsevich do satisfy this conjecture for
a slightly modified definition of universal positivity in which one replaces
the positive atlas consisting of the clusters by an enlargement we call the
scattering atlas. In particular, this uniquely characterizes the theta
functions.


title:
Approximating Min-Cost Chain-Constrained Spanning Trees: A Reduction
  from Weighted to Unweighted Problems

abstract:
  We study the {\em min-cost chain-constrained spanning-tree} (abbreviated
\mcst) problem: find a min-cost spanning tree in a graph subject to degree
constraints on a nested family of node sets. We devise the {\em first} polytime
algorithm that finds a spanning tree that (i) violates the degree constraints
by at most a constant factor {\em and} (ii) whose cost is within a constant
factor of the optimum. Previously, only an algorithm for {\em unweighted} \cst
was known \cite{olver}, which satisfied (i) but did not yield any cost bounds.
This also yields the first result that obtains an $O(1)$-factor for {\em both}
the cost approximation and violation of degree constraints for any
spanning-tree problem with general degree bounds on node sets, where an edge
participates in a super-constant number of degree constraints.
  A notable feature of our algorithm is that we {\em reduce} \mcst to
unweighted \cst (and then utilize \cite{olver}) via a novel application of {\em
Lagrangian duality} to simplify the {\em cost structure} of the underlying
problem and obtain a decomposition into certain uniform-cost subproblems.
  We show that this Lagrangian-relaxation based idea is in fact applicable more
generally and, for any cost-minimization problem with packing side-constraints,
yields a reduction from the weighted to the unweighted problem. We believe that
this reduction is of independent interest. As another application of our
technique, we consider the {\em $k$-budgeted matroid basis} problem, where we
build upon a recent rounding algorithm of \cite{BansalN16} to obtain an
improved $n^{O(k^{1.5}/\epsilon)}$-time algorithm that returns a solution that
satisfies (any) one of the budget constraints exactly and incurs a
$(1+\epsilon)$-violation of the other budget constraints.


title: Georgia Tech Catalog of Gravitational Waveforms

abstract:
  This paper introduces a catalog of gravitational waveforms from the bank of
simulations by the numerical relativity effort at Georgia Tech. Currently, the
catalog consists of 452 distinct waveforms from more than 600 binary black hole
simulations: 128 of the waveforms are from binaries with black hole spins
aligned with the orbital angular momentum, and 324 are from precessing binary
black hole systems. The waveforms from binaries with non-spinning black holes
have mass-ratios $q = m_1/m_2 \le 15$, and those with precessing, spinning
black holes have $q \le 8$. The waveforms expand a moderate number of orbits in
the late inspiral, the burst during coalescence, and the ring-down of the final
black hole. Examples of waveforms in the catalog matched against the widely
used approximate models are presented. In addition, predictions of the mass and
spin of the final black hole by phenomenological fits are tested against the
results from the simulation bank. The role of the catalog in interpreting the
GW150914 event and future massive binary black-hole search in LIGO is
discussed. The Georgia Tech catalog is publicly available at
einstein.gatech.edu/catalog.


title:
Profit-aware Team Grouping in Social Networks: A Generalized Cover
  Decomposition Approach

abstract:
  In this paper, we investigate the profit-aware team grouping problem in
social networks. We consider a setting in which people possess different skills
and compatibility among these individuals is captured by a social network.
Here, we assume a collection of tasks, where each task requires a specific set
of skills, and yields a different profit upon completion. Active and qualified
individuals may collaborate with each other in the form of \emph{teams} to
accomplish a set of tasks. Our goal is to find a grouping method that maximizes
the total profit of the tasks that these teams can complete. Any feasible
grouping must satisfy the following three conditions: (i) each team possesses
all skills required by the task, (ii) individuals within the same team are
social compatible, and (iii) each individual is not overloaded. We refer to
this as the \textsc{TeamGrouping} problem. Our work presents a detailed
analysis of the computational complexity of the problem, and propose a LP-based
approximation algorithm to tackle it and its variants. Although we focus on
team grouping in this paper, our results apply to a broad range of optimization
problems that can be formulated as a cover decomposition problem.


title: Radiative nucleon capture with quasi-separable potentials

abstract:
  We study radiative capture reactions using quasi-separable potentials. This
procedure allows an easier treatment of non-local effects that can be extended
to three-body problems. Using this technique, we calculate the neutron and
proton radiative capture cross sections on $^{12}$C. The results obtained are
shown to be in good agreement with the available experimental data.


title: Topological String Theory Revisited I: The Stage

abstract:
  In this note we reformulate topological string theory using supermanifolds
and supermoduli spaces, following the approach worked out by Witten for
superstring perturbation theory in arXiv:1209.5461. We intend to make the
construction geometrical in nature, by using supergeometry techniques
extensively. The goal is to establish the foundation of studying topological
string amplitudes in terms of integration over appropriate supermoduli spaces.


title: Representations of Max-Stable Processes via Exponential Tilting

abstract:
  The recent contribution Dieker & Mikosch (2015) [1] obtained important
representations of max-stable stationary Brown-Resnick random fields $\zeta_Z$
with a spectral representation determined by a Gaussian process $Z$. With
motivations from \cite{DM} we derive for some general $Z$, representations for
$\zeta_Z$ via exponential tilting of $Z$. Our main findings concern a)
Dieker-Mikosch representations of max-stable processes, b) two-sided extensions
of stationary max-stable processes, c) inf-argmax representation of any
max-stable distribution, and d) new formulas for generalised Pickands
constants. Our applications include new conditions for the stationarity of
$\zeta_Z$, a characterisation of Gaussian random vectors and an alternative
proof of Kabluchko's characterisation of Gaussian processes with stationary
increments.


title: Vocabulary Manipulation for Neural Machine Translation

abstract:
  In order to capture rich language phenomena, neural machine translation
models have to use a large vocabulary size, which requires high computing time
and large memory usage. In this paper, we alleviate this issue by introducing a
sentence-level or batch-level vocabulary, which is only a very small sub-set of
the full output vocabulary. For each sentence or batch, we only predict the
target words in its sentence-level or batch-level vocabulary. Thus, we reduce
both the computing time and the memory usage. Our method simply takes into
account the translation options of each word or phrase in the source sentence,
and picks a very small target vocabulary for each sentence based on a
word-to-word translation model or a bilingual phrase library learned from a
traditional machine translation model. Experimental results on the large-scale
English-to-French task show that our method achieves better translation
performance by 1 BLEU point over the large vocabulary neural machine
translation system of Jean et al. (2015).


title: Exponential state estimation, entropy and Lyapunov exponents

abstract:
  In this paper we study the notion of estimation entropy recently established
by Liberzon and Mitra. This quantity measures the smallest rate of information
about the state of a dynamical system above which an exponential state
estimation with a given exponent is possible. We show that this concept is
closely related to the $\alpha$-entropy introduced by Thieullen and we give a
lower estimate in terms of Lyapunov exponents assuming that the system
preserves an absolutely continuous measure with a bounded density, which
includes in particular Hamiltonian and symplectic systems. Although in its
current form mainly interesting from a theoretical point of view, our result
could be a first step towards a more practical analysis of state estimation
under communication constraints.


title: A long-lived spin-orbit-coupled degenerate dipolar Fermi gas

abstract:
  We describe the creation of a long-lived spin-orbit-coupled gas of quantum
degenerate atoms using the most magnetic fermionic element, dysprosium.
Spin-orbit-coupling arises from a synthetic gauge field created by the
adiabatic following of degenerate dressed states comprised of optically coupled
components of an atomic spin. Because of dysprosium's large electronic orbital
angular momentum and large magnetic moment, the lifetime of the gas is limited
not by spontaneous emission from the light-matter coupling, as for gases of
alkali-metal atoms, but by dipolar relaxation of the spin. This relaxation is
suppressed at large magnetic fields due to Fermi statistics. We observe
lifetimes up to 400 ms, which exceeds that of spin-orbit-coupled fermionic
alkali atoms by a factor of 10-100, and is close to the value obtained from a
theoretical model. Elastic dipolar interactions are also observed to influence
the Rabi evolution of the spin, revealing an interacting fermionic system. The
long lifetime of this weakly interacting spin-orbit-coupled degenerate Fermi
gas will facilitate the study of quantum many-body phenomena manifest at longer
timescales, with exciting implications for the exploration of exotic
topological quantum liquids.


title:
$K$-essence model from the mechanical approach point of view: coupled
  scalar field and the late cosmic acceleration

abstract:
  In this paper, we consider the Universe at the late stage of its evolution
and deep inside the cell of uniformity. At these scales, we can consider the
Universe to be filled with dust-like matter in the form of discretely
distributed galaxies, a $K$-essence scalar field, playing the role of dark
energy, and radiation as matter sources. We investigate such a Universe in the
mechanical approach. This means that the peculiar velocities of the
inhomogeneities (in the form of galaxies) as well as the fluctuations of the
other perfect fluids are non-relativistic. Such fluids are designated as
coupled because they are concentrated around the inhomogeneities. In the
present paper, we investigate the conditions under which the $K$-essence scalar
field with the most general form for its action can become coupled. We
investigate at the background level three particular examples of the
$K$-essence models: (i) the pure kinetic $K$-essence field, (ii) a $K$-essence
with a constant speed of sound and (iii) the $K$-essence model with the
Lagrangian $bX+cX^2-V(\phi)$. We demonstrate that if the $K$-essence is
coupled, all these $K$-essence models take the form of multicomponent perfect
fluids where one of the component is the cosmological constant. Therefore, they
can provide the late-time cosmic acceleration and be simultaneously compatible
with the mechanical approach.


title:
Numerical solution of the generalized Kadomtsev-Petviashvili equations
  with compact finite difference schemes

abstract:
  We propose compact finite difference schemes to solve the KP equations $u\_t
+ u\_{xxx} + u^p u\_x + $\lambda$ \partial^{--1}\_x u\_{yy} = 0$. When $p = 1$,
this equation describes the propagation of small amplitude long waves in
shallow water with weak transverse effects. We first present the numerical
schemes which are compared to the Fourier spectral method. After establishing
the numerical convergence, the scheme is validated. We then depict the behavior
of solutions in the context of solitons instabilities and the blow-up.


title:
Simultaneous Approximation Terms for Multi-Dimensional
  Summation-by-Parts Operators

abstract:
  This paper is concerned with the accurate, conservative, and stable
imposition of boundary conditions and inter-element coupling for
multi-dimensional summation-by-parts (SBP) finite-difference operators. More
precisely, the focus is on diagonal-norm SBP operators that are not based on
tensor products and are applicable to unstructured grids composed of arbitrary
elements. We show how penalty terms --- simultaneous approximation terms (SATs)
--- can be adapted to discretizations based on multi-dimensional SBP operators
to enforce boundary and interface conditions. A general SAT framework is
presented that leads to conservative and stable discretizations of the
variable-coefficient advection equation. This framework includes the case where
there are no nodes on the boundary of the SBP element at which to apply
penalties directly. This is an important generalization, because elements
analogous to Legendre-Gauss collocation, \ie without boundary nodes, typically
have higher accuracy for the same number of degrees of freedom. Symmetric and
upwind examples of the general SAT framework are created using a decomposition
of the symmetric part of an SBP operator; these particular SATs enable the
pointwise imposition of boundary and inter-element conditions. We illustrate
the proposed SATs using triangular-element SBP operators with and without nodes
that lie on the boundary. The accuracy, conservation, and stability properties
of the resulting SBP-SAT discretizations are verified using linear advection
problems with spatially varying divergence-free velocity fields.


title:
Polymer quantization in the Bogoliubov's regime for a homogeneous
  one-dimensional Bose-Einstein condensate

abstract:
  In the present report we analyze the eventual modifications caused by the
polymer quantization upon the ground state of a homogeneous one-dimensional
Bose-Einstein condensate. We obtain the ground state energy of the
corresponding N-body system and, consequently, the corresponding speed of
sound, allowing us to explore the sensitivity of the system to corrections
caused by the polymer quantization. The corrections arising from the polymer
quantization can be improved for dense systems together with small values of
the corresponding one-dimensional scattering length. However, these corrections
remain constrained due to finite size effects of the system. The contributions
of the polymer length scale to the properties of the ground state energy of the
system allow us to explore, as a first approximation and when the Bogoliubov's
formalism is valid, the sensitivity of this many-body system to traces caused
by the discreteness of space suggested by the polymer quantization.


title:
J-GEM Follow-Up Observations to Search for an Optical Counterpart of The
  First Gravitational Wave Source GW150914

abstract:
  We present our optical follow-up observations to search for an
electromagnetic counterpart of the first gravitational wave source GW150914 in
the framework of the Japanese collaboration for Gravitational wave
ElectroMagnetic follow-up (J-GEM), which is an observing group utilizing
optical and radio telescopes in Japan, as well as those in New Zealand, China,
South Africa, Chile, and Hawaii. We carried out a wide-field imaging survey
with Kiso Wide Field Camera (KWFC) on the 1.05-m Kiso Schmidt telescope in
Japan and a galaxy-targeted survey with Tripole5 on the B&C 61-cm telescope in
New Zealand. Approximately 24 deg2 regions in total were surveyed in i-band
with KWFC and 18 nearby galaxies were observed with Tripole5 in g-, r-, and
i-bands 4-12 days after the gravitational wave detection. Median 5-sigma depths
are i~18.9 mag for the KWFC data and g~18.9 mag, r~18.7 mag, and i~18.3 mag for
the Tripole5 data. Probability for a counterpart to be in the observed area is
1.2% in the initial skymap and 0.1% in the final skymap. We do not find any
transient source associated to an external galaxy with spatial offset from its
center, which is consistent with the local supernova rate. We summarize future
prospects and ongoing efforts to pin down electromagnetic counterparts of
binary black hole mergers as well as neutron star mergers.


title:
The Nevanlinna-type parametrization for the operator Hamburger moment
  problem

abstract:
  In this paper we obtain a Nevanlinna-type parametrization for the operator
Hamburger moment problem. The moment problem is not supposed to be necessarily
completely indeterminate. No assumptions besides the solvability of the moment
problem are posed.


title:
Transfer of energy in Camassa-Holm and related models by use of
  nonunique characteristics

abstract:
  We study the propagation of energy density in finite-energy weak solutions of
the Camassa-Holm and related equations. Developing the methods based on
generalized nonunique characteristics, we show that the parts of energy related
to positive and negative slopes are one-sided weakly continuous and of bounded
variation, which allows us to define certain measures of dissipation of both
parts of energy. The result is a step towards the open problem of uniqueness of
dissipative solutions of the Camassa-Holm equation.


title: Bosonic Partition Functions

abstract:
  The behavior of quenched Dirac spectra of two-dimensional lattice QCD is
consistent with spontaneous chiral symmetry breaking which is forbidden
according to the Coleman-Mermin-Wagner theorem. One possible resolution of this
paradox is that, because of the bosonic determinant in the partially quenched
partition function, the conditions of this theorem are violated allowing for
spontaneous symmetry breaking in two dimensions or less. This goes back to work
by Niedermaier and Seiler on nonamenable symmetries of the hyperbolic spin
chain and earlier work by two of the auhtors on bosonic partition functions at
nonzero chemical potential. In this talk we discuss chiral symmetry breaking
for the bosonic partition function of QCD at nonzero isospin chemical potential
and a bosonic random matrix theory at imaginary chemical potential and compare
the results with the fermionic counterpart. In both cases the chiral symmetry
group of the bosonic partition function is noncompact.


title: A very general quartic double fourfold is not stably rational

abstract:
  We prove that a very general double cover of the projective four-space,
ramified in a quartic threefold, is not stably rational.


title:
Extented Paley-Wiener type theorems for the Mellin and Fourier
  transforms on the half-real line

abstract:
  In this paper we present generalisations of Paley-Wiener type theorems to
Mellin and (Laplace-)Fourier transforms of rapidly decreasing smooth functions
with positive support and log-polyhomogeneous asymptotic expansion at zero.
This article is based on the thesis \cite{CdC} and uses results borrowed from
\cite{RS}, \cite{RS81}, \cite{P79}, \cite{FGD}, \cite{P79}, \cite{SZ}.


title: Action Recognition in Video Using Sparse Coding and Relative Features

abstract:
  This work presents an approach to category-based action recognition in video
using sparse coding techniques. The proposed approach includes two main
contributions: i) A new method to handle intra-class variations by decomposing
each video into a reduced set of representative atomic action acts or
key-sequences, and ii) A new video descriptor, ITRA: Inter-Temporal Relational
Act Descriptor, that exploits the power of comparative reasoning to capture
relative similarity relations among key-sequences. In terms of the method to
obtain key-sequences, we introduce a loss function that, for each video, leads
to the identification of a sparse set of representative key-frames capturing
both, relevant particularities arising in the input video, as well as relevant
generalities arising in the complete class collection. In terms of the method
to obtain the ITRA descriptor, we introduce a novel scheme to quantify relative
intra and inter-class similarities among local temporal patterns arising in the
videos. The resulting ITRA descriptor demonstrates to be highly effective to
discriminate among action categories. As a result, the proposed approach
reaches remarkable action recognition performance on several popular benchmark
datasets, outperforming alternative state-of-the-art techniques by a large
margin.


title: Fixed-Point Methods on Small-Signal Stability Analysis

abstract:
  In this paper we introduce the Diagonal Dominant Pole Spectrum Eigensolver
(DDPSE), which is a fixed-point method that computes several eigenvalues of a
matrix at a time. DDPSE is a slight modification of the Dominant Pole Spectrum
Eigensolver (DPSE), that has being used in power system stability studies. We
show that both methods have local quadratic convergence. Moreover, we present
practical results obtained by both methods, from which we can see that those
methods really compute dominant poles of a transfer function of the type
$c^T(A-sI)^{-1}b$, where $b$ and $c$ are vectors, besides being also effective
in finding low damped modes of a large scale power system.


title: Gamma-ray Signals from Dark Matter Annihilation Via Charged Mediators

abstract:
  We consider a simplified model in which Majorana fermion dark matter
annihilates to charged fermions through exchange of charged mediators. We
consider the gamma-ray signals arising from the processes $XX \rightarrow \bar
f f \gamma$, $\gamma \gamma$, and $\gamma Z$ in the most general case,
including non-trivial fermion mass and non-trivial left-right mixing and
$CP$-violating phase for the charged mediators. In particular, we find the most
general spectrum for internal bremsstrahlung, which interpolates between the
regimes dominated by virtual internal bremsstrahlung and by final state
radiation. We also examine the variation in the ratio $\sigma(\gamma \gamma) /
\sigma (\gamma Z)$ and the helicity asymmetry in the $XX \rightarrow \gamma
\gamma$ process, each as a function of mixing angle and $CP$-violating phase.
As an application, we apply these results to searches for a class of MSSM
models.


title: Fermion self-energy in magnetized chirally asymmetric QED matter

abstract:
  The fermion self-energy is calculated for a cold QED plasma with chiral
chemical potential in a magnetic field. It is found that a momentum shift
parameter dynamically generated in such a plasma leads to a modification of the
chiral magnetic effect current. It is argued that the momentum shift parameter
can be relevant for the evolution of magnetic field in the chirally asymmetric
primordial plasma in the early Universe.


title:
Surface bundles over surfaces: new inequalities between signature,
  simplicial volume and Euler characteristic

abstract:
  We present three new inequalities tying the signature, the simplicial volume
and the Euler characteristic of surface bundles over surfaces. Two of them are
true for any surface bundle, while the third holds on a specific family of
surface bundles, namely the ones that arise through a ramified covering. These
are the main known examples of bundles with non-zero signature.


title:
A mechanization of the Blakers-Massey connectivity theorem in Homotopy
  Type Theory

abstract:
  This paper continues investigations in "synthetic homotopy theory": the use
of homotopy type theory to give machine-checked proofs of constructions from
homotopy theory
  We present a mechanized proof of the Blakers-Massey connectivity theorem, a
result relating the higher-dimensional homotopy groups of a pushout type
(roughly, a space constructed by gluing two spaces along a shared subspace) to
those of the components of the pushout. This theorem gives important
information about the pushout type, and has a number of useful corollaries,
including the Freudenthal suspension theorem, which has been studied in
previous formalizations.
  The new proof is more elementary than existing ones in abstract
homotopy-theoretic settings, and the mechanization is concise and high-level,
thanks to novel combinations of ideas from homotopy theory and type theory.


title: iHDG: An Iterative HDG Framework for Partial Differential Equations

abstract:
  We present a scalable iterative solver for high-order hybridized
discontinuous Galerkin (HDG) discretizations of linear partial differential
equations. It is an interplay between domain decomposition methods and HDG
discretizations, and hence inheriting advances from both sides. In particular,
the method can be viewed as a Gauss-Seidel approach that requires only
independent element-by-element and face-by-face local solves in each iteration.
As such, it is well-suited for current and future computing systems with
massive concurrencies. Unlike conventional Gauss-Seidel schemes which are
purely algebraic, the convergence of iHDG, thanks to the built-in HDG numerical
flux, does not depend on the ordering of unknowns. We rigorously show the
convergence of the proposed method for the transport equation, the linearized
shallow water equation and the convection-diffusion equation. For the transport
equation, the method is convergent regardless of mesh size $h$ and solution
order $p$, and furthermore the convergence rate is independent of the solution
order. For the linearized shallow water and the convection-diffusion equations
we show that the convergence is conditional on both $h$ and $p$. Extensive
steady and time-dependent numerical results for the 2D and 3D transport
equations, the linearized shallow water equation, and the convection-diffusion
equation are presented to verify the theoretical findings.


title:
CORDIC-based Architecture for Powering Computation in Fixed-Point
  Arithmetic

abstract:
  We present a fixed point architecture (source VHDL code is provided) for
powering computation. The fully customized architecture, based on the expanded
hyperbolic CORDIC algorithm, allows for design space exploration to establish
trade-offs among design parameters (numerical format, number of iterations),
execution time, resource usage and accuracy. We also generate Pareto-optimal
realizations in the resource-accuracy space: this approach can produce optimal
hardware realizations that simultaneously satisfy resource and accuracy
requirements.


title: Super-Resolution MIMO Radar

abstract:
  A multiple input, multiple output (MIMO) radar emits probings signals with
multiple transmit antennas and records the reflections from targets with
multiple receive antennas. Estimating the relative angles, delays, and Doppler
shifts from the received signals allows to determine the locations and
velocities of the targets. Standard approaches to MIMO radar based on digital
matched filtering or compressed sensing only resolve the angle-delay-Doppler
triplets on a $(1/(N_T N_R), 1/B,1/T)$ grid, where $N_T$ and $N_R$ are the
number of transmit and receive antennas, $B$ is the bandwidth of the probing
signals, and $T$ is the length of the time interval over which the reflections
are observed. In this work, we show that the \emph{continuous}
angle-delay-Doppler triplets and the corresponding attenuation factors can be
recovered perfectly by solving a convex optimization problem. This result holds
provided that the angle-delay-Doppler triplets are separated either by $10/(N_T
N_R-1)$ in angle, $10.01/B$ in delay, or $10.01/T$ in Doppler direction.
Furthermore, this result is optimal (up to log factors) in the number of
angle-delay-Doppler triplets that can be recovered.


title: Wick Rotation and Fermion Doubling in Noncommutative Geometry

abstract:
  In this paper, we discuss two features of the noncommmutative geometry and
spectral action approach to the Standard Model: the fact that the model is
inherently Euclidean, and that it requires a quadrupling of the fermionic
degrees of freedom. We show how the two issues are intimately related. We give
a precise prescription for the Wick rotation from the Euclidean theory to the
Lorentzian one, eliminating the extra degrees of freedom. This requires not
only projecting out mirror fermions, as has been done so far, and which leads
to the correct Pfaffian, but also the elimination of the remaining extra
degrees of freedom. The remaining doubling has to be removed in order to
recover the correct Fock space of the physical (Lorentzian) theory. In order to
get a Spin(1,3) invariant Lorentzian theory from a Spin(4) invariant Euclidean
theory such an elimination must be performed after the Wick rotation.
Differences between the Euclidean and Lorentzian case are described in detail,
in a pedagogical way.


title: The Polarizable Embedding Density Matrix Renormalization Group Method

abstract:
  The polarizable embedding (PE) approach is a flexible embedding model where a
pre-selected region out of a larger system is described quantum mechanically
while the interaction with the surrounding environment is modeled through an
effective operator. This effective operator represents the environment by
atom-centered multipoles and polarizabilities derived from quantum mechanical
calculations on (fragments of) the environment. Thereby, the polarization of
the environment is explicitly accounted for. Here, we present the coupling of
the PE approach with the density matrix renormalization group (DMRG). This
PE-DMRG method is particularly suitable for embedded subsystems that feature a
dense manifold of frontier orbitals which requires large active spaces.
Recovering such static electron-correlation effects in multiconfigurational
electronic structure problems, while accounting for both electrostatics and
polarization of a surrounding environment, allows us to describe strongly
correlated electronic structures in complex molecular environments. We
investigate various embedding potentials for the well-studied first excited
state of water with active spaces that correspond to a full
configuration-interaction treatment. Moreover, we study the environment effect
on the first excited state of a retinylidene Schiff base within a
channelrhodopsin protein. For this system, we also investigate the effect of
dynamical correlation included through short-range density functional theory.

categories: physics.chem-ph cond-mat.mtrl-sci cond-mat.str-el physics.comp-ph


title:
Comprehensive All-sky Search for Periodic Gravitational Waves in the
  Sixth Science Run LIGO Data

abstract:
  We report on a comprehensive all-sky search for periodic gravitational waves
in the frequency band 100-1500 Hz and with a frequency time derivative in the
range of $[-1.18, +1.00]\times 10^{-8}$ Hz/s. Such a signal could be produced
by a nearby spinning and slightly non-axisymmetric isolated neutron star in our
galaxy. This search uses the data from the Initial LIGO sixth science run and
covers a larger parameter space with respect to any past search.
  A Loosely Coherent detection pipeline was applied to follow up weak outliers
in both Gaussian (95% recovery rate) and non-Gaussian (75% recovery rate)
bands. No gravitational wave signals were observed, and upper limits were
placed on their strength. Our smallest upper limit on worst-case (linearly
polarized) strain amplitude $h_0$ is ${9.7}\times 10^{-25}$ near 169 Hz, while
at the high end of our frequency range we achieve a worst-case upper limit of
${5.5}\times 10^{-24}$. Both cases refer to all sky locations and entire range
of frequency derivative values.


title:
Measurement Bounds for Sparse Signal Reconstruction with Multiple Side
  Information

abstract:
  In the context of compressed sensing (CS), this paper considers the problem
of reconstructing sparse signals with the aid of other given correlated sources
as multiple side information. To address this problem, we theoretically study a
generic \textcolor{black}{weighted $n$-$\ell_{1}$ minimization} framework and
propose a reconstruction algorithm that leverages multiple side information
signals (RAMSI). The proposed RAMSI algorithm computes adaptively optimal
weights among the side information signals at every reconstruction iteration.
In addition, we establish theoretical bounds on the number of measurements that
are required to successfully reconstruct the sparse source by using
\textcolor{black}{weighted $n$-$\ell_{1}$ minimization}. The analysis of the
established bounds reveal that \textcolor{black}{weighted $n$-$\ell_{1}$
minimization} can achieve sharper bounds and significant performance
improvements compared to classical CS. We evaluate experimentally the proposed
RAMSI algorithm and the established bounds using synthetic sparse signals as
well as correlated feature histograms, extracted from a multiview image
database for object recognition. The obtained results show clearly that the
proposed algorithm outperforms state-of-the-art
algorithms---\textcolor{black}{including classical CS, $\ell_1\text{-}\ell_1$
minimization, Modified-CS, regularized Modified-CS, and weighted $\ell_1$
minimization}---in terms of both the theoretical bounds and the practical
performance.


title: Review of Nucleon Decay Searches at Super-Kamiokande

abstract:
  Baryon number violation appears in many contexts. It is a requirement for
baryogenesis and is a consequence of Grand Unified Theories (GUTs), which
predict nucleon decay. Nucleon decay searches provide the most direct way to
test baryon number conservation and also serve as a unique probe of GUT scale
physics around $10^{14-16}$ GeV. Such energies cannot be reached directly by
accelerators. However, they can be explored indirectly at large underground
water Cherenkov (WC) experiments, which due to the size of their fiducial
volume are highly sensitive to nucleon decays. We review searches for baryon
number violating processes at the state of the art WC detector, the
Super-Kamiokande. Analyses of the typically dominant non-SUSY and SUSY nucleon
decay channels such as $p \rightarrow (e^+, \mu^+) \pi^0$ and $p \rightarrow
\nu K^+$, as well as more exotic searches, will be discussed. Presented studies
set the world's best limits, which circumvent the allowed parameter space of
theoretical models


title:
Delay-aware Fountain Codes for Video Streaming with Optimal Sampling
  Strategy

abstract:
  The explosive demand of on-line video from smart mobile devices poses
unprecedented challenges to delivering high quality of experience (QoE) over
wireless networks. Streaming high-definition video with low delay is difficult
mainly due to (i) the stochastic nature of wireless channels and (ii) the
fluctuating videos bit rate. To address this, we propose a novel delay-aware
fountain coding (DAF) technique that integrates channel coding and video
coding. In this paper, we reveal that the fluctuation of video bit rate can
also be exploited to further improve fountain codes for wireless video
streaming. Specifically, we develop two coding techniques: the time-based
sliding window and the optimal window-wise sampling strategy. By adaptively
selecting the window length and optimally adjusting the sampling pattern
according to the ongoing video bit rate, the proposed schemes deliver
significantly higher video quality than existing schemes, with low delay and
constant data rate. To validate our design, we implement the protocols of DAF,
DAF-L (a low-complexity version) and the existing delay-aware video streaming
schemes by streaming H.264/AVC standard videos over an 802.11b network on CORE
emulation platform. The results show that the decoding ratio of our scheme is
15% to 100% higher than the state of the art techniques.


title: Partially Natural Two Higgs Doublet Models

abstract:
  It is possible that the electroweak scale is low due to the fine-tuning of
microscopic parameters, which can result from selection effects. The
experimental discovery of new light fundamental scalars other than the Standard
Model Higgs boson would seem to disfavor this possibility, since generically
such states imply parametrically worse fine-tuning with no compelling
connection to selection effects. We discuss counterexamples where the Higgs
boson is light because of fine-tuning, and a second scalar doublet is light
because a discrete symmetry relates its mass to the mass of the Standard Model
Higgs boson. Our examples require new vectorlike fermions at the electroweak
scale, and the models possess a rich electroweak vacuum structure. The
mechanism that we discuss does not protect a small CP-odd Higgs mass in split
or high-scale supersymmetry-breaking scenarios of the MSSM due to an
incompatibility between the discrete symmetries and holomorphy.


title:
Ultra-sensitive label-free in-situ detection of dynamically driven
  self-assembly of 2D nanoplatelets on SOI chip

abstract:
  Fluid dispersed two-dimensional (2D) composite materials with dynamically
tunable functional properties have recently emerged as a novel highly promising
class of optoelectronic materials, opening up new routes not only for the
emerging field of metamaterials but also to chip-scale multifunctional
metadevices. However, in-situ monitoring and detection of the dynamic ordering
of 2D nanoparticles on chip and during the device operation is still a huge
challenge. Here we introduce a novel approach for on-chip, in-situ Raman
characterisation of 2D-fluid composite materials incorporated into Si photonics
chip. In this work the Raman signal for 2D nanoplatelets is selectively
enhanced by Fabry-Perot resonator design of CMOS photonic-compatible
microfluidic channels. This has then been extended to demonstrate the first
in-situ Raman detection of the dynamics of individual 2D nanoplatelets, within
a microfluidic channel. Our work paves the way for the first practicable
realisation of 3D photonic microstructure shaping based on 2D-fluid composites
and CMOS photonics platform.


title: Spectral type, temperature and evolutionary stage in cool supergiants

abstract:
  In recent years, temperature scales in cool supergiants (CSGs) have been
disputed, and the possibility that spectral types (SpTs) do not depend
primarily on temperature has been raised. We explore the relations between
different observed parameters and the capability of deriving accurate intrinsic
stellar parameters from them through the analysis of the largest spectroscopic
sample of CSGs to date from SMC and LMC. We explore possible correlations
between different observational parameters, also making use of near- and
mid-infrared colours and literature on photometric variability. Direct
comparison between the behaviour of atomic lines (Fe I, Ti I, and Ca II) in the
observed spectra and synthetic atmospheric models provides compelling evidence
that effective temperature is the prime underlying variable driving the SpT
sequence in CSGs. However, there is a clear correlation between SpT and
luminosity, with later ones tending to correspond to more luminous stars with
heavier mass loss. The population of CSGs in the SMC is characterised by a
higher degree of spectral variability, early spectral types (centred on type
K1) and low mass-loss rates (at least as measured by dust-sensitive
mid-infrared colours). The population in the LMC displays less spectroscopic
variability and later spectral types. The distribution of spectral types is not
single-peaked. Instead, the brightest CSGs have a significantly different
distribution from less luminous objects, presenting mostly M subtypes (centred
on M2), and increasing mass-loss rates for later types. In conclusion, the
observed properties of CSGs in the SMC and the LMC cannot be described
correctly by standard evolutionary models. The very strong correlation between
spectral type and bolometric luminosity, supported by all data from the Milky
Way, cannot be reproduced at all by current evolutionary tracks.


title:
Limiting Absorption Principle, Generalized Eigenfunctions and Scattering
  Matrix for Laplace Operators with Boundary conditions on Hypersurfaces

abstract:
  We provide a limiting absorption principle for the self-adjoint realizations
of Laplace operators corresponding to boundary conditions on (relatively open
parts $\Sigma$ of) compact hypersurfaces $\Gamma=\partial\Omega$,
$\Omega\subset{\mathbb{R}}^{n}$. For any of such self-adjoint operators we also
provide the generalized eigenfunctions and the scattering matrix; both these
objects are written in terms of operator-valued Weyl functions. We make use of
a Krein-type formula which provides the resolvent difference between the
operator corresponding to self-adjoint boundary conditions on the hypersurface
and the free Laplacian on the whole space ${\mathbb{R}}^{n}$. Our results apply
to all standard examples of boundary conditions, like Dirichlet, Neumann,
Robin, $\delta$ and $\delta'$-type, either assigned on $\Gamma$ or on
$\Sigma\subset\Gamma$.


title:
Forward Reachable Sets: Analytically derived properties of connected
  components for dynamic networks

abstract:
  Formal analysis of the emergent structural properties of dynamic networks is
largely uncharted territory. We focus here on the properties of forward
reachable sets (FRS) as a function of the underlying degree distribution and
edge duration. FRS are defined as the set of nodes that can be reached from an
initial seed via a path of temporally ordered edges; a natural extension of
connected component measures to dynamic networks. Working in a stochastic
framework, we derive closed-form expressions for the mean and variance of the
exponential growth rate of the FRS for temporal networks with both edge and
node dynamics. For networks with node dynamics, we calculate thresholds for the
growth of the FRS. The effects of finite population size are explored via
simulation and approximation. We examine how these properties vary by edge
duration and different cross-sectional degree distributions that characterize a
range of scientifically interesting normative outcomes (Poisson and Bernoulli).
The size of the forward reachable set gives an upper bound for the epidemic
size in disease transmission network models, relating this work to epidemic
modeling (Ferguson 2000, Eames 2004).


title: TU Comae Berenices : Blazhko RR Lyrae Star in a Potential Binary System

abstract:
  We present the results of a photometry campaign of TU Com performed over a
five-year time span. The analysis showed that the possible Blazhko period of 75
days published by the General Catalogue of Variable Stars is not correct. We
identified two Blazhko periods of 43.6 and 45.5 days. This finding is based on
measurement of 124 light maxima. A spectral analysis of the complete light
curve confirmed these two periods. Besides the Blazhko amplitude and phase
modulations, another long term periodic phase variation has been identified.
This long term periodic variation affects the times of maximum light only and
can be attributed to a light-travel time effect due to orbital motion of a
binary system. The orbital parameters have been estimated by a nonlinear
least-square fit applied to the set of (O-C) values. The Levenberg-Marquart
algorithm has been used to perform the nonlinear least-square fit. The
tentative orbital parameters include an orbital period of 1676 days, a minimal
semi-major axis of 1.55 AU and a small eccentricity of 0.22. The orbital
parameter estimation also used 33 (O-C) values obtained from the SWASP survey
database. Spectroscopic radial velocity measurements are needed to confirm this
binarity. If confirmed, TU Com would be the first Blazhko RR Lyrae star
detected in a binary system.


title:
On "Exponential Lower Bounds for Polytopes in Combinatorial
  Optimization" by Fiorini et al. (2015): A Refutation For Models With Disjoint
  Sets of Descriptive Variables

abstract:
  We provide a numerical refutation of the developments of Fiorini et al.
(2015)* for models with disjoint sets of descriptive variables. We also provide
an insight into the meaning of the existence of a one-to-one linear map between
solutions of such models.
  *: Fiorini, S., S. Massar, S. Pokutta, H.R. Tiwary, and R. de Wolf (2015).
Exponential Lower Bounds for Polytopes in Combinatorial Optimization. Journal
of the ACM 62:2, Article No. 17.


title:
A Stochastic Geometric Analysis of Device-to-Device Communications
  Operating over Generalized Fading Channels

abstract:
  Device-to-device (D2D) communications are now considered as an integral part
of future 5G networks which will enable direct communication between user
equipment (UE) without unnecessary routing via the network infrastructure. This
architecture will result in higher throughputs than conventional cellular
networks, but with the increased potential for co-channel interference induced
by randomly located cellular and D2D UEs. The physical channels which
constitute D2D communications can be expected to be complex in nature,
experiencing both line-of-sight (LOS) and non-LOS (NLOS) conditions across
closely located D2D pairs. As well as this, given the diverse range of
operating environments, they may also be subject to clustering of the scattered
multipath contribution, i.e., propagation characteristics which are quite
dissimilar to conventional Rayeligh fading environments. To address these
challenges, we consider two recently proposed generalized fading models, namely
$\kappa-\mu$ and $\eta-\mu$, to characterize the fading behavior in D2D
communications. Together, these models encompass many of the most widely
encountered and utilized fading models in the literature such as Rayleigh, Rice
(Nakagami-$n$), Nakagami-$m$, Hoyt (Nakagami-$q$) and One-Sided Gaussian. Using
stochastic geometry we evaluate the rate and bit error probability of D2D
networks under generalized fading conditions. Based on the analytical results,
we present new insights into the trade-offs between the reliability, rate, and
mode selection under realistic operating conditions. Our results suggest that
D2D mode achieves higher rates over cellular link at the expense of a higher
bit error probability. Through numerical evaluations, we also investigate the
performance gains of D2D networks and demonstrate their superiority over
traditional cellular networks.


title: Kahler-Einstein and Kahler scalar flat supermanifolds

abstract:
  Two results regarding K\"ahler supermanifolds with potential
$K=A+C\theta\bar\theta$ are shown. First, if the supermanifold is
K\"ahler-Einstein, then its base (the supermanifold of one lower fermionic
dimension and with K\"ahler potential $A$) has constant scalar curvature. As a
corollary, every constant scalar curvature K\"ahler supermanifold has a unique
superextension to a K\"ahler-Einstein supermanifold of one higher fermionic
dimension. Second, if the supermanifold is itself scalar flat, then its base
satisfies the equation $$ \phi^{\bar ji}\phi_{i\bar j}=2\Delta_0 S_0 +
R_0^{\bar ji}R_{0i\bar j} - S_0^2, $$ where $\Delta_0$ is the Laplace operator,
$S_0$ is the scalar curvature, and $R_{0i\bar j}$ is the Ricci tensor of the
base, and $\phi$ is some harmonic section on the base. Remarkably, precisely
this equation arises in the construction of certain supergravity
compactifications. Examples of bosonic manifolds satisfying the equation above
are discussed.


title:
Analysis of 3D-printed metal for rapid-prototyped reflective terahertz
  optics

abstract:
  We explore the potential of 3D metal printing to realize complex conductive
terahertz devices. Factors impacting performance such as printing resolution,
surface roughness, oxidation, and material loss are investigated via
analytical, numerical, and experimental approaches. The high degree of control
offered by a 3D-printed topology is exploited to realize a zone plate operating
at 530 GHz. Reflection efficiency at this frequency is found to be over 90%.
The high-performance of this preliminary device suggest that 3D metal printing
can play a strong role in guided-wave and general beam control devices in the
terahertz range.


title:
Almost global existence for cubic nonlinear Schr\"odinger equations in
  one space dimension

abstract:
  We consider non-gauge-invariant cubic nonlinear Schr\"odinger equations in
one space dimension. We show that initial data of size $\varepsilon$ in a
weighted Sobolev space lead to solutions with sharp $L_x^\infty$ decay up to
time $\exp(C\varepsilon^{-2})$. We also exhibit norm growth beyond this time
for a specific choice of nonlinearity.


title:
Massive vector particles tunneling from black holes influenced by the
  generalized uncertainty principle

abstract:
  This study considers the generalized uncertainty principle, which
incorporates the central idea of large extra dimensions, to investigate the
processes involved when massive spin-1 particles tunnel from Reissner-Nordstrom
and Kerr black holes under the effects of quantum gravity. For the black hole,
the quantum gravity correction decelerates the increase in temperature. Up to
$\mathcal{O}(\frac{1}{M_f^2})$, the corrected temperatures are affected by the
mass and angular momentum of the emitted vector bosons. In addition, the
temperature of the Kerr black hole becomes uneven due to rotation. When the
mass of the black hole approaches the order of the higher dimensional Planck
mass $M_f$, it stops radiating and yields a black hole remnant.


title:
Faceted interfaces: a key feature to quantitative understanding of
  transformation morphology

abstract:
  Faceted interfaces are a key feature in self-resembling morphologies of many
microstructures generated from solid state phase transformations.
Interpretations, predictions and simulations of the faceted morphologies remain
a challenge, especially for systems in which irrational orientation
relationships (ORs) between two phases and irrational interface orientations
(IOs) are preferred. In terms of structural singularities, this work suggests
an integrated framework, which possibly encompasses all candidates of faceted
interfaces. The structural singularities are identified in a matching pattern,
a dislocation structure and/or a ledge structure. The resultant singular
interfaces are discrete IOs, described with low index g's (rational
orientations) and/or Delta-g's (either rational or irrational orientations).
Elimination of defects exerts restrictions on the OR and the lattice
parameters. Various models are grouped according to their determined results
regarding the OR and IO, and the links between the models are clarified in the
integrated framework. An irrational IO is usually due to elimination of
dislocations in one direction, i.e., an O-line interface. Analytical methods
using both 3D and 2D models for quantitative determinations of O-line
interfaces are reviewed, and a detailed example showing the calculation for an
irrational interface is given. The association between structural singularities
and local energy minima is verified by atomistic calculations of interfacial
energies in fcc/bcc alloys where it is found that the calculated equilibrium
cross-sections are in a good agreement with observations from selected alloys.


title: Universal quantum computation with a nonlinear oscillator network

abstract:
  It has recently been shown that a parametrically driven oscillator with Kerr
nonlinearity yields a Schr\"odinger cat state via quantum adiabatic evolution
through its bifurcation point and a network of such nonlinear oscillators can
be used for solving combinatorial optimization problems by bifurcation-based
adiabatic quantum computation [H. Goto, Sci. Rep. \textbf{6}, 21686 (2016)].
Here we theoretically show that such a nonlinear oscillator network with
controllable parameters can also be used for universal quantum computation. The
initialization is achieved by a quantum-mechanical bifurcation based on quantum
adiabatic evolution, which yields a Schr\"odinger cat state. All the elementary
quantum gates are also achieved by quantum adiabatic evolution, in which
dynamical phases accompanying the adiabatic evolutions are controlled by the
system parameters. Numerical simulation results indicate that high gate
fidelities can be achieved, where no dissipation is assumed.


title: QCD unitarity constraints on Reggeon Field Theory

abstract:
  We point out that the $s$-channel unitarity of QCD imposes meaningful
constraints on a possible form of the QCD Reggeon Field Theory. We show that
neither the BFKL nor JIMWLK nor Braun's Hamiltonian satisfy the said
constraints. In a toy, zero transverse dimensional case we construct a model
that satisfies the analogous constraint and show that at infinite energy it
indeed tends to a "black disk limit" as opposed to the model with triple
Pomeron vertex only, routinely used as a toy model in the literature.


title: Switching current distributions in InAs nanowire Josephson junctions

abstract:
  We report on the switching current distributions in nano-hybrid Josephson
junctions made of InAs semiconductor nanowires. Temperature dependence of the
switching current distribution can be understood by motion of Josephson phase
particle escaping from a tilted washboard potential, fitted well to the
macroscopic quantum tunneling, thermal activation and phase diffusion models,
depending on temperature. Application of gate voltage to tune the Josephson
coupling strength enables us to adjust the effective temperature for the
escaping process, which would be promising for developing gate-tunable
superconducting phase qubits.


title: Tellurene-a monolayer of tellurium from first-principles prediction

abstract:
  A two dimensional (2D) Group-VI Te monolayer, tellurene, is predicted by
using the first-principles calculations, which consists of planner
four-membered and chair-like six-membered rings arranged alternately in a 2D
lattice. The phonon spectra calculations, combined with ab initio molecular
dynamics (MD) simulations, demonstrate that tellurene is kinetically very
stable. The tellurene shows a desirable direct band gap of 1.04 eV and its band
structure can be effectively tuned by strain. The effective mass calculations
imply that tellurene should also exhibit a relatively high carrier mobility,
e.g. compared with MoS2. The significant direct band gap and the high carrier
mobility imply that tellurene is a very promising candidate for a new
generation of nanoelectronic devices.


title:
Molecular Dynamics Simulation Study of Carbon-Nanotube Oscillator in
  Graphene Nanoribbon Trench

abstract:
  Graphene/carbon-nanotube (CNT) hybrid material can be useful in energy
storage and nanoelectronic technologies. Here we address the CNT-oscillator
encapsulated in a graphene-nanoribbon (GNR) trench as a novel design, and
investigate its properties via classical molecular dynamics simulations. Since
the energy barrier was very low while the CNT was encapsulated in the GNR
trench, the CNT absorbed on the GNR surface could easily be encapsulated in the
GNR trench. MD simulations showed that the CNT oscillator encapsulated in a GNR
trench is compatible with simple CNT oscillators, so we anticipate that the CNT
in GNR trench could work as an oscillator. So we can anticipate that the CNT
encapsulated in a GNR trench can be applied to ultra-sensitive
nanoelectromechanical oscillators, and this system has the possibility to be
applied to relay-switching devices, and to shuttle memory.


title: The magnetic properties of the planet host star Kepler-78

abstract:
  Kepler-78 is host to a transiting 8.5-hour orbit super-Earth. In this paper,
the rotation and magnetic properties of the planet host star are studied. We
first revisit the Kepler photometric data for a detailed description of the
rotation properties of Kepler-78, showing that the star seems to undergo a
cycle in the spot pattern of ~1,300 day duration. We then use
spectropolarimetric observations with CFHT/ESPaDOnS to measure the circular
polarization in the line profile of the star during its rotation cycle, as well
as spectroscopic proxies of the chromospheric activity. The average field has
an amplitude of 16 G. The magnetic topology is characterized by a poloidal and
a toroidal component, encompassing 60% and 40% of the magnetic energy,
respectively. Differential rotation is detected with an estimated rate of
0.105+-0.039 rad/d. Activity tracers vary with the rotation cycle of the star;
there is no hint that a residual activity level is related to the planetary
orbit at the precision of our data. The description of the star magnetic
field's characteristics then may serve as input for models of interactions
between the star and its close-by planet, e.g., Ohmic dissipation and unipolar
induction.


title:
Observation of $e^{+}e^{-} \to \eta^{\prime} J/\psi$ at center-of-mass
  energies between 4.189 and 4.600 GeV

abstract:
  The process $e^{+}e^{-}\to \eta^{\prime} J/\psi$ is observed for the first
time with a statistical significance of $8.6\sigma$ at center-of-mass energy
$\sqrt{s} = 4.226$ GeV and $7.3\sigma$ at $\sqrt{s} = 4.258$ GeV using data
samples collected with the BESIII detector. The Born cross sections are
measured to be $(3.7 \pm 0.7 \pm 0.3)$ and $(3.9 \pm 0.8 \pm 0.3)$ pb at
$\sqrt{s} = 4.226$ and $4.258$ GeV, respectively, where the first errors are
statistical and the second systematic. Upper limits at the 90% confidence level
of the Born cross sections are also reported at other 12 energy points.


title: Order three normalizers of 2-groups

abstract:
  This paper examines order three elements of finite groups which normalize no
nontrivial 2-subgroup. The motivation for finding such elements arises out of a
problem in modular representation theory. The question of when these elements
appear in the almost simple groups was posed by Geoff Robinson in the context
of studying 2-blocks of defect zero. For the almost simple groups, a complete
classification of order three elements with this property is determined. On the
basis of this result, necessary conditions are then given for the existence of
such elements in a large class of finite groups.


title:
Configurational entropy of polar glass formers and the effect of
  electric field on glass transition

abstract:
  A model of low-temperature polar liquids is constructed that accounts for
configurational heat capacity, entropy, and the effect of a strong electric
field on the glass transition. The model is based on Pad{\'e}-truncated
perturbation expansions of the liquid state theory. Depending on parameters, it
accommodates an ideal glass transition of vanishing configurational entropy and
its avoidance, with a square-root divergent enumeration function at the point
of its termination. A composite density-temperature parameter $\rho^\gamma/T$,
often used to represent combined pressure and temperature data, follows from
the model. The theory is in good agreement with experimental data for excess
(over the crystal state) thermodynamics of molecular glass formers. We suggest
that the Kauzmann entropy crisis might be a signature of vanishing
configurational entropy of a subset of degrees of freedom, multipolar rotations
in our model. This scenario has observable consequences: (i) a dynamical
cross-over of the relaxation time and (ii) the fragility index defined by the
ratio of the excess heat capacity and excess entropy at the glass transition.
The Kauzmann temperature of vanishing configurational entropy, and the
corresponding glass transition temperature, shift upward when the electric
field is applied. The temperature shift scales quadratically with the field
strength.


title: Deep Attributes Driven Multi-Camera Person Re-identification

abstract:
  The visual appearance of a person is easily affected by many factors like
pose variations, viewpoint changes and camera parameter differences. This makes
person Re-Identification (ReID) among multiple cameras a very challenging task.
This work is motivated to learn mid-level human attributes which are robust to
such visual appearance variations. And we propose a semi-supervised attribute
learning framework which progressively boosts the accuracy of attributes only
using a limited number of labeled data. Specifically, this framework involves a
three-stage training. A deep Convolutional Neural Network (dCNN) is first
trained on an independent dataset labeled with attributes. Then it is
fine-tuned on another dataset only labeled with person IDs using our defined
triplet loss. Finally, the updated dCNN predicts attribute labels for the
target dataset, which is combined with the independent dataset for the final
round of fine-tuning. The predicted attributes, namely \emph{deep attributes}
exhibit superior generalization ability across different datasets. By directly
using the deep attributes with simple Cosine distance, we have obtained
surprisingly good accuracy on four person ReID datasets. Experiments also show
that a simple metric learning modular further boosts our method, making it
significantly outperform many recent works.


title: Lifshitz holographic superconductor in Horava-Lifshitz gravity

abstract:
  We study the holographic phase transition of superconductor dual to a
Lifshitz black brane probed by an anisotropic scalar field in the probe limit
in Ho\u{r}ava-Lifshitz gravity. With the use of numerical and analytical
method, we investigate how the critical temperature of the condensation is
affected by the Lifshitz exponent $z$, $\alpha-$correction term in the action
as well as the dimensions of the gravity. We also numerically explore the
condensation of the dual operator and optical conductivity of the holographic
system. Various interesting properties of the holographic condensation affected
by the parameters of model are discussed.


title:
Sensorimotor Input as a Language Generalisation Tool: A Neurorobotics
  Model for Generation and Generalisation of Noun-Verb Combinations with
  Sensorimotor Inputs

abstract:
  The paper presents a neurorobotics cognitive model to explain the
understanding and generalisation of nouns and verbs combinations when a vocal
command consisting of a verb-noun sentence is provided to a humanoid robot.
This generalisation process is done via the grounding process: different
objects are being interacted, and associated, with different motor behaviours,
following a learning approach inspired by developmental language acquisition in
infants. This cognitive model is based on Multiple Time-scale Recurrent Neural
Networks (MTRNN).With the data obtained from object manipulation tasks with a
humanoid robot platform, the robotic agent implemented with this model can
ground the primitive embodied structure of verbs through training with
verb-noun combination samples. Moreover, we show that a functional hierarchical
architecture, based on MTRNN, is able to generalise and produce novel
combinations of noun-verb sentences. Further analyses of the learned network
dynamics and representations also demonstrate how the generalisation is
possible via the exploitation of this functional hierarchical recurrent
network.


title: pyJac: analytical Jacobian generator for chemical kinetics

abstract:
  Accurate simulations of combustion phenomena require the use of detailed
chemical kinetics in order to capture limit phenomena such as ignition and
extinction as well as predict pollutant formation. However, the chemical
kinetic models for hydrocarbon fuels of practical interest typically have large
numbers of species and reactions and exhibit high levels of mathematical
stiffness in the governing differential equations, particularly for larger fuel
molecules. In order to integrate the stiff equations governing chemical
kinetics, generally reactive-flow simulations rely on implicit algorithms that
require frequent Jacobian matrix evaluations. Some in situ and a posteriori
computational diagnostics methods also require accurate Jacobian matrices,
including computational singular perturbation and chemical explosive mode
analysis. Typically, finite differences numerically approximate these, but for
larger chemical kinetic models this poses significant computational demands
since the number of chemical source term evaluations scales with the square of
species count. Furthermore, existing analytical Jacobian tools do not optimize
evaluations or support emerging SIMD processors such as GPUs. Here we introduce
pyJac, a Python-based open-source program that generates analytical Jacobian
matrices for use in chemical kinetics modeling and analysis. As a
demonstration, we first establish the correctness of the Jacobian matrices for
kinetic models of hydrogen, methane, ethylene, and isopentanol oxidation, then
demonstrate the performance achievable on CPUs and GPUs using pyJac via matrix
evaluation timing comparisons.


title: Local homological properties and cyclicity of homogeneous ANR compacta

abstract:
  In accordance with the Bing-Borsuk conjecture \cite{bb}, we show that if $X$
is an $n$-dimensional homogeneous metric $ANR$ compactum and $x\in X$, then
there is a local basis at x consisting of connected open sets U such that the
homological properties of \bar U and bdU are similar to the properties of the
closed ball B^n in R^n and its boundary S^{n-1}. We discuss also the following
questions raised by Bing-Borsuk, where X is a homogeneous ANR-compactum with
dim X=n: Is it true that $X$ is cyclic in dimension n? Is it true that no
non-empty closed subset of X, acyclic in dimension n-$, separates X? It is
shown that both questions have positive answers simultaneously, and a positive
solution to each one of them implies a solution to another question of
Bing-Borsuk (whether every finite-dimensional homogenous metric AR-compactum is
a point).


title: On the existence of $F$-thresholds and related limits

abstract:
  The $F$-thresholds are important numerical invariants in prime
characteristic, whose existence had been established only under certain
assumptions. We show the existence of $F$-thresholds in full generality. We
study properties of standard graded algebras over a field for which $F$-pure
threshold and $F$-threshold at the irrelevant maximal ideal agree. We also
exhibit explicit bounds for the $a$-invariants and Castelnuovo-Mumford
regularity of Frobenius powers of ideals in terms of $F$-thresholds and
$F$-pure thresholds, obtaining existence of related limits in certain cases.


title: Homological selections and fixed-point theorems

abstract:
  A homological selection theorem for C-spaces, as well as, a
finite-dimensional homological selection theorem is established. We apply the
finite-dimensional homological selection theorem to obtain fixed-point theorems
for usco homologically UV^n set-valued maps.


title: A Quantum Approach to the Unique Sink Orientation Problem

abstract:
  We consider quantum algorithms for the unique sink orientation problem on
cubes. This problem is widely considered to be of intermediate computational
complexity. This is because there no known polynomial algorithm (classical or
quantum) from the problem and yet it arrises as part of a series of problems
for which it being intractable would imply complexity theoretic collapses. We
give a reduction which proves that if one can efficiently evaluate the kth
power of the unique sink orientation outmap, then there exists a polynomial
time quantum algorithm for the unique sink orientation problem on cubes.


title:
Generalized Sparse Precision Matrix Selection for Fitting Multivariate
  Gaussian Random Fields to Large Data Sets

abstract:
  We present a new method for estimating multivariate, second-order stationary
Gaussian Random Field (GRF) models based on the Sparse Precision matrix
Selection (SPS) algorithm, proposed by Davanloo et al. (2015) for estimating
scalar GRF models. Theoretical convergence rates for the estimated
between-response covariance matrix and for the estimated parameters of the
underlying spatial correlation function are established. Numerical tests using
simulated and real datasets validate our theoretical findings. Data
segmentation is used to handle large data sets.


title:
Strongly Enhanced and Directionally Tunable Second-Harmonic Radiation by
  a Plasmonic Particle-in-Cavity Nanoantenna

abstract:
  Second-harmonic (SH) generation is tremendously important for nonlinear
sensing, microscopy and communication system. One of the great challenges of
current designs is to enhance the SH signal and simultaneously tune its
radiation direction with a high directivity. In contrast to the linear
plasmonic scattering dominated by a bulk dipolar mode, a complex
surface-induced multipolar source at the doubled frequency sets a fundamental
limit to control the SH radiation from metallic nanostructures. In this work,
we harness plasmonic hybridization mechanism together with a special selection
rule governing the SH radiation to achieve the high-intensity and
tunable-direction emission by a metallic particle-in-cavity nanoantenna
(PIC-NA). The nanoantenna is modelled with a first-principle, self-consistent
boundary element method, which considers the depletion of pump waves. The giant
SH enhancement arises from a hybridized gap plasmon resonance between the small
particle and the large cavity that functions as a concentrator and reflector.
Centrosymmetry breaking of the PIC-NA not only modifies the gap plasmon mode
boosting the SH signal, but also redirects the SH wave with a unidirectional
emission. The PIC-NA has a significantly larger SH conversion efficiency
compared to existing literature. The main beam of the radiation pattern can be
steered over a wide angle by tuning the particle's position.


title: A Hierarchical Emotion Regulated Sensorimotor Model: Case Studies

abstract:
  Inspired by the hierarchical cognitive architecture and the perception-action
model (PAM), we propose that the internal status acts as a kind of
common-coding representation which affects, mediates and even regulates the
sensorimotor behaviours. These regulation can be depicted in the Bayesian
framework, that is why cognitive agents are able to generate behaviours with
subtle differences according to their emotion or recognize the emotion by
perception. A novel recurrent neural network called recurrent neural network
with parametric bias units (RNNPB) runs in three modes, constructing a
two-level emotion regulated learning model, was further applied to testify this
theory in two different cases.


title: Testing the Binary Trigger Hypothesis in FUors

abstract:
  We present observations of three FU Orionis objects (hereafter, FUors) with
nonredundant aperture-mask interferometry (NRM) at 1.59 um and 2.12 um that
probe for binary companions on the scale of the protoplanetary disk that feeds
their accretion outbursts. We do not identify any companions to V1515 Cyg or
HBC 722, but we do resolve a close binary companion to V1057 Cyg that is at the
diffraction limit (rho = 58.3 +/- 1.4 mas or 30 +/- 5 AU) and currently much
fainter than the outbursting star (delta(K') = 3.34 +/- 0.10 mag). Given the
flux excess of the outbursting star, we estimate that the mass of the companion
(M ~ 0.25 Msun) is similar to or slightly below that of the FUor itself, and
therefore it resembles a typical T Tauri binary system. Our observations only
achieve contrast limits of delta(K') ~ 4 mag, and hence we are only sensitive
to companions that were near or above the pre-outburst luminosity of the FUors.
It remains plausible that FUor outbursts could be tied to the presence of a
close binary companion. However, we argue from the system geometry and mass
reservoir considerations that these outbursts are not directly tied to the
orbital period (i.e., occurring at periastron passage), but instead must only
occur infrequently.


title: A Fast 2-Approximation Algorithm for Guarding Orthogonal Terrains

abstract:
  Terrain Guarding Problem(TGP), which is known to be NP-complete, asks to find
a smallest set of guard locations on a terrain $T$ such that every point on $T$
is visible by a guard. Here, we study this problem on 1.5D orthogonal terrains
where the edges are bound to be horizontal or vertical. We propose a
2-approximation algorithm that runs in O($n \log m$) time, where $n$ and $m$
are the sizes of input and output, respectively. This is an improvement over
the previous best algorithm, which is a 2-approximation with O($n^2$) running
time.


title:
Resonant inelastic X-ray scattering response of the Kitaev honeycomb
  model

abstract:
  We calculate the resonant inelastic X-ray scattering (RIXS) response of the
Kitaev honeycomb model, an exactly solvable quantum-spin-liquid model with
fractionalized Majorana and flux excitations. We find that the fundamental RIXS
channels, the spin-conserving (SC) and the non-spin-conserving (NSC) ones, do
not interfere and give completely different responses. SC-RIXS picks up
exclusively the Majorana sector with a pronounced momentum dispersion, whereas
NSC-RIXS also creates immobile fluxes, thereby rendering the response only
weakly momentum dependent, as in the spin structure factor measured by
inelastic neutron scattering. RIXS can therefore pick up the fractionalized
excitations of the Kitaev spin liquid separately, making it a sensitive probe
to detect spin-liquid character in potential material incarnations of the
Kitaev honeycomb model.


title: Bar Simplicial Modules and Secondary Cyclic (Co)homology

abstract:
  In this paper we study the simplicial structure of the complex
$C^{\bullet}((A,B,\varepsilon); M)$, associated to the secondary Hochschild
cohomology. The main ingredient is the simplicial object
$\mathcal{B}(A,B,\varepsilon)$, which plays a role equivalent to that of the
bar resolution associated to an algebra. We also introduce the secondary cyclic
(co)homology and establish some of its properties (Theorems 3.9 and 4.11).


title:
Classification of trivial spin-1 tensor network states on a square
  lattice

abstract:
  Classification of possible quantum spin liquid (QSL) states of interacting
spin-1/2's in two dimensions has been a fascinating topic of condensed matter
for decades, resulting in enormous progress in our understanding of
low-dimensional quantum matter. By contrast, relatively little work exists on
the identification, let alone classification, of QSL phases for spin-1 systems
in dimensions higher than one. Employing the powerful ideas of tensor network
theory and its classification, we develop general methods for writing QSL wave
functions of spin-1 respecting all the lattice symmetries, spin rotation, and
time reversal with trivial gauge structure on the square lattice. We find $2^5$
distinct classes characterized by five binary quantum numbers. Several explicit
constructions of such wave functions are given for bond dimensions $D$ ranging
from two to four, along with thorough numerical analyses to identify their
physical characters. Both gapless and gapped states are found. The topological
entanglement entropy of the gapped states are close to zero, indicative of
topologically trivial states. In $D=4$, several different tensors can be
linearly combined to produce a family of states within the same symmetry class.
A rich "phase diagram" can be worked out among the phases of these tensors, as
well as the phase transitions among them. Among the states we identified in
this putative phase diagram is the plaquette-ordered phase, gapped resonating
valence bond phase, and a critical phase. A continuous transition separates the
plaquette-ordered phase from the resonating valence bond phase.


title: Complements to Classic Topics of Circles Geometry

abstract:
  We approach several themes of classical geometry of the circle and complete
them with some original results, showing that not everything in traditional
math is revealed, and that it still has an open character. The topics were
chosen according to authors aspiration and attraction, as a poet writes lyrics
about spring according to his emotions.


title: Inhomogeneous Jacobi matrices on trees

abstract:
  We study Jacobi matrices on trees with one end at inifinity. We show that the
defect indices cannot be greater than 1 and give criteria for essential
selfadjointness. We construct certain polynomials associated with matrices,
which mimic orthogonal polynomials in the classical case. Nonnegativity of
Jacobi matrices is studied as well.


title: Lattice Induced Transparency in Metasurfaces

abstract:
  Lattice modes are intrinsic to the periodic structures and their occurrence
can be easily tuned and controlled by changing the lattice constant of the
structural array. Previous studies have revealed excitation of sharp absorption
resonances due to lattice mode coupling with the plasmonic resonances. Here, we
report the first experimental observation of a lattice induced transparency
(LIT) by coupling the first order lattice mode (FOLM) to the structural
resonance of a metamaterial resonator at terahertz frequencies. The observed
sharp transparency is a result of the destructive interference between the
bright mode and the FOLM mediated dark mode. As the FOLM is swept across the
metamaterial resonance, the transparency band undergoes large change in its
bandwidth and resonance position. Besides controlling the transparency
behaviour, LIT also shows a huge enhancement in the Q-factor and record high
group delay of 28 ps, which could be pivotal in ultrasensitive sensing and slow
light device applications.