title: On Hybrid Pilot for Channel Estimation in Massive MIMO Uplink

abstract:
  This paper introduces a hybrid pilot-aided channel estimation technique for
mitigating the effect of pilot contamination for the uplink of multi-cell
multiuser massive MIMO systems. The proposed hybrid pilot is designed such that
it enjoys the complementary advantages between time-multiplexed (TM) pilot and
time-superimposed (TS) pilot, and thereby, allows superior solution to the
conventional pilot schemes. We mathematically characterize the impact of hybrid
pilot on the massive MIMO uplink by deriving a closed-form approximation for
the uplink achievable rate. In large-number-of-antennas regime, we obtain the
asymptotically optimal solution for hybrid pilot by jointly designing the TM
pilot and the TS pilot. It is shown that either TM pilot or TS pilot has the
advantages for large frame-size and limited frame-size transmission,
respectively, while the hybrid pilot scheme can offer a superior performance to
that employing either TM pilot or TS pilot. Numerical results demonstrate the
effectiveness of the proposed design.


title: Rotational evolution of magnetars in the presence of a fallback disk

abstract:
  Magnetars may have strong surface dipole field. Observationally, two
magnetars may have passive fallback disks. In the presence of a fallback disk,
the rotational evolution of magnetars may be changed. In the self-similar
fallback disk model, it is found that: (1) When the disk mass is significantly
smaller than $10^{-6} \,\rm M_{\odot}$, the magnetar is unaffected by the
fallback disk and it will be a normal magnetar. (2) When the disk mass is
large, but the magnetar's surface dipole field is about or below $10^{14} \,\rm
G$, the magnetar will also be a normal magnetar. A magnetar plus a passive
fallback disk system is expected. This may correspond to the observations of
magnetars 4U 0142$+$61, and 1E 2259$+$586. (3) When the disk mass is large, and
the magnetar's surface dipole field is as high as $4\times 10^{15} \,\rm G$,
the magnetar will evolve from the ejector phase to the propeller phase, and
then enter rotational equilibrium. The magnetar will be slowed down quickly in
the propeller phase. The final rotational period can be as high $2\times 10^4
\,\rm s$. This may correspond to the super-slow magnetar in the supernova
remnant RCW 103. Therefore, the three kinds of magnetars can be understood in a
unified way.


title:
Formation and settling of a disc galaxy during the last 8 billion years
  in a cosmological simulation

abstract:
  We present results of a high-resolution zoom cosmological simulation of the
evolution of a low-mass galaxy with a maximum velocity of V=100 km/s at z=0,
using the initial conditions from the AGORA project (Kim et al. 2014). The
final disc-dominated galaxy is consistent with local disc scaling relations,
such as the stellar-to-halo mass relation and the baryonic Tully-Fisher. The
galaxy evolves from a compact, dispersion-dominated galaxy into a
rotation-dominated but dynamically hot disc in about 0.5 Gyr (from z=1.4 to
z=1.2). The disc dynamically cools down for the following 7 Gyr, as the gas
velocity dispersion decreases over time, in agreement with observations. The
primary cause of this slow evolution of velocity dispersion in this low-mass
galaxy is stellar feedback. It is related to the decline in gas fraction, and
to the associated gravitational disk instability, as the disc slowly settles
from a global Toomre Q>1 turbulent disc to a marginally unstable disc (Q=1).


title: Modifying horizon thermodynamics by surface tensions

abstract:
  The modified first laws of thermodynamics at the black hole horizon and the
cosmological horizon of the Schwarzschild de Sitter black hole and the apparent
horizon of the Friedmann-Robertson-Walker cosmology are derived by the surface
tensions, respectively. The corresponding Smarr relations are obeyed. For the
black hole, the cosmological constant is first treated as a fixed constant, and
then as a variable associated to the pressure. The law at the apparent horizon
takes the same form as that at the cosmological horizon, but is different from
that at the black hole horizon. The positive temperatures guarantee the
appearance of the worked terms in the modified laws at the cosmological and
apparent horizons. While they can disappear at the black hole horizon.


title: Renormalized oscillation theory for Hamiltonian systems

abstract:
  We extend a result on renormalized oscillation theory, originally derived for
Sturm-Liouville and Dirac-type operators on arbitrary intervals in the context
of scalar coefficients, to the case of general Hamiltonian systems with block
matrix coefficients. In particular, this contains the cases of general
Sturm-Liouville and Dirac-type operators with block matrix-valued coefficients
as special cases.
  The principal feature of these renormalized oscillation theory results
consists in the fact that by replacing solutions by appropriate Wronskians of
solutions, oscillation theory now applies to intervals in essential spectral
gaps where traditional oscillation theory typically fails.


title: HyperLex: A Large-Scale Evaluation of Graded Lexical Entailment

abstract:
  We introduce HyperLex - a dataset and evaluation resource that quantifies the
extent of of the semantic category membership, that is, type-of relation also
known as hyponymy-hypernymy or lexical entailment (LE) relation between 2,616
concept pairs. Cognitive psychology research has established that typicality
and category/class membership are computed in human semantic memory as a
gradual rather than binary relation. Nevertheless, most NLP research, and
existing large-scale invetories of concept category membership (WordNet,
DBPedia, etc.) treat category membership and LE as binary. To address this, we
asked hundreds of native English speakers to indicate typicality and strength
of category membership between a diverse range of concept pairs on a
crowdsourcing platform. Our results confirm that category membership and LE are
indeed more gradual than binary. We then compare these human judgements with
the predictions of automatic systems, which reveals a huge gap between human
performance and state-of-the-art LE, distributional and representation learning
models, and substantial differences between the models themselves. We discuss a
pathway for improving semantic models to overcome this discrepancy, and
indicate future application areas for improved graded LE systems.


title:
Connecting Radiative Neutrino Mass, Neutron-Antineutron Oscillation,
  Proton Decay, and Leptogenesis through Dark Matter

abstract:
  The scotogenic mechanism for radiative neutrino mass is generalized to
include neutron-antineutron oscillation as well as proton decay. Dark matter is
stabilized by extending the notion of lepton parity to matter parity.
Leptogenesis is also a possible byproduct. This framework unifies the
description of all these important, but seemingly unrelated, topics in physics
beyond the standard model of particle interactions.


title:
Transition probabilities for degenerate diffusions arising in population
  genetics

abstract:
  We provide a detailed description of the structure of the transition
probabilities and of the hitting distributions of boundary components of a
manifold with corners for a degenerate strong Markov process arising in
population genetics. The Markov processes that we study are a generalization of
the classical Wright-Fisher process. The main ingredients in our proofs are
based on the analysis of the regularity properties of solutions to a forward
Kolmogorov equation defined on a compact manifold with corners, which is
degenerate in the sense that it is not strictly elliptic and the coefficients
of the first order drift term have mild logarithmic singularities.


title: Dressing Method for the Degasperis-Procesi Equation

abstract:
  The soliton solutions of the Degasperis-Procesi equations are constructed by
the implementation of the dressing method. The form of the one and two soliton
solutions coincides with the form obtained by Hirota's method.


title: Inflation from Supergravity with Gauged R-symmetry in de Sitter Vacuum

abstract:
  We study the cosmology of a recent model of supersymmetry breaking, in the
presence of a tuneable positive cosmological constant, based on a gauged shift
symmetry of a string modulus that can be identified with the string dilaton.
The minimal spectrum of the `hidden' supersymmetry breaking sector consists
then of a vector multiplet that gauges the shift symmetry of the dilaton
multiplet and when coupled to the MSSM leads to a distinct low energy
phenomenology depending on one parameter. Here we study the question if this
model can also lead to inflation by identifying the dilaton with the inflaton.
We find that this is possible if the K\"ahler potential is modified by a term
that has the form of NS5-brane instantons, leading to an appropriate
inflationary plateau around the maximum of the scalar potential, depending on
two extra parameters. This model is consistent with present cosmological
observations without modifying the low energy particle phenomenology associated
to the minimum of the scalar potential.


title:
Simultaneous measurement of mass and rotation of trapped absorbing
  particles in air

abstract:
  We trap absorbing micro-particles in air by photophoretic forces generated
using a single loosely focused Gaussian trapping beam. We measure a component
of the radial Brownian motion of a trapped particle cluster and determine the
power spectral density, mean squared displacement, and normalized position and
velocity autocorrelation functions in order to characterize the photophoretic
body force in a quantitative fashion for the first time. The trapped particles
also undergo spontaneous rotation due to the action of this force. This is
evident from the spectral density that displays clear peaks at the rotation and
the particles' inertial resonance frequencies. We fit the spectral density to
the well-known analytical function derived from the Langevin equation, measure
the resonance and rotation frequencies and determine values for particle mass
that we verify at different trapping laser powers with reasonable accuracy.


title: Searching for Dark Absorption with Direct Detection Experiments

abstract:
  We consider the absorption by bound electrons of dark matter in the form of
dark photons and axion-like particles, as well as of dark photons from the Sun,
in current and next-generation direct detection experiments. Experiments
sensitive to electron recoils can detect such particles with masses between a
few eV to more than 10 keV. For dark photon dark matter, we update a previous
bound based on XENON10 data and derive new bounds based on data from XENON100
and CDMSlite. We find these experiments to disfavor previously allowed
parameter space. Moreover, we derive sensitivity projections for SuperCDMS at
SNOLAB for silicon and germanium targets, as well as for various possible
experiments with scintillating targets (cesium iodide, sodium iodide, and
gallium arsenide). The projected sensitivity can probe large new regions of
parameter space. For axion-like particles, the same current direction detection
data improves on previously known direct-detection constraints but does not
bound new parameter space beyond known stellar cooling bounds. However,
projected sensitivities of the upcoming SuperCDMS SNOLAB using germanium can go
beyond these and even probe parameter space consistent with possible hints from
the white dwarf luminosity function. We find similar results for dark photons
from the sun. For all cases, direct-detection experiments can have
unprecedented sensitivity to dark-sector particles.


title:
Theory of unidirectional spin Hall magnetoresistance in
  heavy-metal/ferromagnetic-metal bilayers

abstract:
  Recent experiments have revealed nonlinear features of the magnetoresistance
in metallic bilayers consisting of a heavy-metal (HM) and a ferromagnetic metal
(FM). A small change in the lon- gitudinal resistance of the bilayer has been
observed when reversing the direction of either the applied in-plane current or
the magnetization. We attribute such nonlinear transport behavior to the
spin-polarization dependence of the electron mobility in the FM layer acting in
concert with the spin accumulation induced in that layer by the spin Hall
current originating in the bulk of the HM layer. An explicit expression for the
nonlinear magnetoresistance is derived based on a simple drift-diffusion model,
which shows that the nonlinear magnetoresistance appears at the first order of
spin Hall angle (SHA), and changes sign when the current is reversed, in
agreement with the experimental observations. We also discuss possible ways to
control the sign of the nonlinear magnetoresistance and to enhance the
magnitude of effect.


title: A new type of unique range set with deficient values

abstract:
  In the paper, we introduce a new type of unique range set for meromorphic
function having deficient values which will improve all the previous result in
this aspect.


title:
How Much Did it Rain? Predicting Real Rainfall Totals Based on Radar
  Data

abstract:
  We applied a variety of parametric and non-parametric machine learning models
to predict the probability distribution of rainfall based on 1M training
examples over a single year across several U.S. states. Our top performing
model based on a squared loss objective was a cross-validated parametric
k-nearest-neighbor predictor that took about six days to compute, and was
competitive in a world-wide competition.


title:
Kink-antikink asymmetry and impurity interactions in topological
  mechanical chains

abstract:
  We study the dynamical response of a diatomic periodic chain of rotors
coupled by springs, whose unit cell breaks spatial inversion symmetry. In the
continuum description, we derive a nonlinear field theory which admits
topological kinks and antikinks as nonlinear excitations but where a
topological boundary term breaks the symmetry between the two and energetically
favors the kink configuration. Using a cobweb plot, we develop a fixed-point
analysis for the kink motion and demonstrate that kinks propagate without the
Peierls-Nabarro potential energy barrier typically associated with lattice
models. Using continuum elasticity theory, we trace the absence of the
Peierls-Nabarro barrier for the kink motion to the topological boundary term
which ensures that only the kink configuration, and not the antikink, costs
zero potential energy. Further, we study the eigenmodes around the kink and
antikink configurations using a tangent stiffness matrix approach appropriate
for pre-stressed structures to explicitly show how the usual energy degeneracy
between the two no longer holds. We show how the kink-antikink asymmetry also
manifests in the way these nonlinear excitations interact with impurities
introduced in the chain as disorder in the spring stiffness. Finally, we
discuss the effect of impurities in the (bond) spring length and build
prototypes based on simple linkages that verify our predictions.


title: Spoofing 2D Face Detection: Machines See People Who Aren't There

abstract:
  Machine learning is increasingly used to make sense of the physical world yet
may suffer from adversarial manipulation. We examine the Viola-Jones 2D face
detection algorithm to study whether images can be created that humans do not
notice as faces yet the algorithm detects as faces. We show that it is possible
to construct images that Viola-Jones recognizes as containing faces yet no
human would consider a face. Moreover, we show that it is possible to construct
images that fool facial detection even when they are printed and then
photographed.


title:
Spin Transfer Torque in the Semiconductor/Ferromagnetic Structure in the
  Presence of Rashba Effect

abstract:
  Spin transfer torque in magnetic structures occurs when the transverse
component of the spin current that flows from the nonmagnetic medium to
ferromagnetic medium are absorbed by the interface. In this paper, considering
the Rashba effect on semiconductor region, we have discussed the spin transfer
torque in semiconductor/ferromagnetic structure and obtained the components of
spin-current density for two models: (I)-single electron and (II)- the
distribution of electrons. We have shown that whatever the difference between
Fermi surfaces in semiconductor and Fermi spheres for the up and down spins in
ferromagnetic increase, the transmission probability decreases. The obtained
results for the values used in this article illustrate that Rashba effect
increases the difference between a Fermi sphere in semiconductors and Fermi
sphere for the up and down spins in ferromagnetic. The results also show that
the Rashba effect, brings an additional contribution to the components of spin
transfer torque, which is not exist in the absence of the Rashba interaction.
Moreover, the Rashba term has also different effects on the transverse
components of the spin torque transfer.


title: Ocular Shock Front in the Colliding Galaxy IC 2163

abstract:
  ALMA observations in the CO 1 - 0 line of the interacting galaxies IC 2163
and NGC 2207 at 2" x 1.5" resolution reveal how the encounter drives gas to
pile up in narrow, ~ 1 kpc wide, "eyelids" in IC 2163. IC 2163 and NGC 2207 are
involved in a grazing encounter, which has led to development in IC 2163 of an
eye-shaped (ocular) structure at mid-radius and two tidal arms. The CO data
show that there are large velocity gradients across the width of each eyelid,
with a mixture of radial and azimuthal streaming of gas at the outer edge of
the eyelid relative to its inner edge. The sense of the radial streaming in the
eyelids is consistent with the idea that gas from the outer part of IC 2163
flows inward until its radial streaming slows down abruptly and the gas piles
up in the eyelids. The radial compression at the eyelids causes an increase in
the gas column density by direct radial impact and also leads to a high rate of
shear. We find a strong correlation between the molecular column densities and
the magnitude of dv/dR across the width of the eyelid at fixed values of
azimuth. Substantial portions of the eyelids have high velocity dispersion in
CO, indicative of elevated turbulence there.


title: The energy of the alphabet model

abstract:
  We call \emph{Alphabet model} a generalization to N types of particles of the
classic ABC model. We have particles of different types stochastically evolving
on a one dimensional lattice with an exchange dynamics. The rates of exchange
are local but under suitable conditions the dynamics is reversible with a
Gibbsian like invariant measure with long range interactions. We discuss
geometrically the conditions of reversibility on a ring that correspond to a
gradient condition on the graph of configurations or equivalently to a
divergence free condition on a graph structure associated to the types of
particles. We show that much of the information on the interactions between
particles can be encoded in associated \emph{Tournaments} that are a special
class of oriented directed graphs. In particular we show that the interactions
of reversible models are corresponding to strongly connected tournaments. The
possible minimizers of the energies are in correspondence with the Hamiltonian
cycles of the tournaments. We can then determine how many and which are the
possible minimizers of the energy looking at the structure of the associated
tournament. As a byproduct we obtain a probabilistic proof of a classic Theorem
of Camion \cite{Camion} on the existence of Hamiltonian cycles for strongly
connected tournaments. Using these results we obtain in the case of an equal
number of k types of particles new representations of the Hamiltonians in terms
of translation invariant $k$-body long range interactions. We show that when
$k=3,4$ the minimizer of the energy is always unique up to translations.
Starting from the case $k=5$ it is possible to have more than one minimizer. In
particular it is possible to have minimizers for which particles of the same
type are not joined together in single clusters.


title:
Password Cracking: The Effect of Hash Function Bias on the Average
  Guesswork

abstract:
  Modern authentication systems store hashed values of passwords of users using
cryptographic hash functions. Therefore, to crack a password an attacker needs
to guess a hash function input that is mapped to the hashed value, as opposed
to the password itself. We call a hash function that maps the same number of
inputs to each bin, as \textbf{unbiased}. However, cryptographic hash functions
in use have not been proven to be unbiased (i.e., they may have an unequal
number of inputs mapped to different bins). A cryptographic hash function has
the property that it is computationally difficult to find an input mapped to a
bin. In this work we introduce a structured notion of biased hash functions for
which we analyze the average guesswork under certain types of brute force
attacks. This work shows that the level of security depends on the set of
hashed values of valid users as well as the statistical profile of a hash
function, resulting from bias. We examine the average guesswork conditioned on
the set of hashed values, and model the statistical profile through the
empirical distribution of the number of inputs that are mapped to a bin. In
particular, we focus on a class of statistical profiles (capturing the bias) ,
which we call type-class statistical profiles, that has an empirical
distribution related to the probability of the type classes defined in the
method of types. For such profiles, we show that the average guesswork is
related to basic measures in information theory such as entropy and divergence.
We use this to show that the effect of bias on the conditional average
guesswork is limited compared to other system parameters such as the number of
valid users who store their hashed passwords in the system.


title: LBCS: the LOFAR Long-Baseline Calibrator Survey

abstract:
  (abridged). We outline LBCS (the LOFAR Long-Baseline Calibrator Survey),
whose aim is to identify sources suitable for calibrating the
highest-resolution observations made with the International LOFAR Telescope,
which include baselines >1000 km. Suitable sources must contain significant
correlated flux density (50-100mJy) at frequencies around 110--190~MHz on
scales of a few hundred mas. At least for the 200--300-km international
baselines, we find around 1 suitable calibrator source per square degree over a
large part of the northern sky, in agreement with previous work. This should
allow a randomly selected target to be successfully phase calibrated on the
international baselines in over 50% of cases. Products of the survey include
calibrator source lists and fringe-rate and delay maps of wide areas --
typically a few degrees -- around each source. The density of sources with
significant correlated flux declines noticeably with baseline length over the
range 200--600~km, with good calibrators on the longest baselines appearing
only at the rate of 0.5 per square degree. Coherence times decrease from 1--3
minutes on 200-km baselines to about 1 minute on 600-km baselines, suggesting
that ionospheric phase variations contain components with scales of a few
hundred kilometres. The longest median coherence time, at just over 3 minutes,
is seen on the DE609 baseline, which at 227km is close to being the shortest.
We see median coherence times of between 80 and 110 seconds on the four longest
baselines (580--600~km), and about 2 minutes for the other baselines. The
success of phase transfer from calibrator to target is shown to be influenced
by distance, in a manner that suggests a coherence patch at 150-MHz of the
order of 1 degree.


title: Regularity of Line Configurations

abstract:
  We show that in arithmetically-Gorenstein line arrangements with only planar
singularities, each line intersects the same number of other lines. This number
has an algebraic interpretation: it is the Castelnuovo-Mumford regularity of
the coordinate ring of the arrangement.
  We also prove that every (d-1)-dimensional simplicial complex whose 0-th and
1-st homologies are trivial is the nerve complex of a suitable d-dimensional
standard graded algebra of depth $\ge 3$. This provides the converse of a
recent result by Katzman, Lyubeznik and Zhang.


title: A nonlocal fractional Helmholtz equation

abstract:
  In this paper we study some boundary value problems for a fractional analogue
of second order elliptic equation with an involution perturbation in a
rectangular domain. Theorems on existence and uniqueness of a solution of the
considered problems are proved by spectral method.


title:
Apparent Non-Coevality among the Stars in Upper Scorpio: Resolving the
  Problem using a Model of Magnetic Inhibition of Convection

abstract:
  Two eclipsing binaries in the USco association have recently yielded precise
values of masses and radii for 4 low-mass members of the association. Standard
evolution models would require these dM4.5 - dM5 stars to have ages which are
younger than the ages of more massive stars in the association by factors which
appear (in extreme cases) to be as large as ~3. Are the stars in the
association therefore non-coeval? We suggest that the answer is No: by
incorporating the effects of magnetic inhibition of convective onset, we show
that the stars in USco can be restored to coevality provided that the 4
low-mass member stars have vertical surface fields in the range 200 - 700 G.
Fields of such magnitude have already been measured on the surface of certain
solar-type stars in other young clusters.


title:
Rotational symmetry of self-expanders to the inverse mean curvature flow
  with cylindrical ends

abstract:
  We show that any complete, immersed self-expander to the inverse mean
curvature flow, which has one end asymptotic to a cylinder, or has two ends
asymptotic to two coaxial cylinders, must be rotationally symmetric.


title:
Quantum Chaos in the Heisenberg Spin Chain: the Effect of
  Dzyaloshinskii-Moriya Interaction

abstract:
  Using one-dimensional spin-1/2 systems as prototypes of quantum many-body
systems, we study the emergence of quantum chaos. The main purpose of this work
is to answer the following question: how does the spin-orbit interaction, as a
pure quantum interaction, may lead to the onset of quantum chaos? We consider
three integrable spin-1/2 systems: the Ising, the XX, and the XXZ limits, and
analyze whether quantum chaos develops or not after the addition of the
Dzyaloshinskii-Moriya interaction. We find that, depending on the strength of
the anisotropy parameter, the answer is positive for the XXZ and Ising models,
while no such evidence is observed for the XX model. We also discuss the
relationship between quantum chaos and thermalization.


title: Homogeneous Painlev\'e II transcendents

abstract:
  We offer elementary proofs for fundamental properties of solutions to the
homogeneous second Painlev\'e equation.


title: Mogami manifolds, nuclei, and 3D simplicial gravity

abstract:
  Mogami introduced in 1995 a large class of triangulated 3-dimensional
pseudomanifolds, henceforth called "Mogami pseudomanifolds". He proved an
exponential bound for the size of this class in terms of the number of
tetrahedra. The question of whether all 3-balls are Mogami has remained open
since, a positive answer would imply a much-desired exponential upper bound for
the total number of 3-balls (and 3-spheres) with N tetrahedra.
  Here we provide a negative answer: many 3-balls are not Mogami. On the way to
this result, we characterize the Mogami property in terms of nuclei, in the
sense of Collet-Eckmann-Younan: "The only three-dimensional Mogami nucleus is
the tetrahedron".


title:
Deviations from Born-Oppenheimer mass scaling in spectroscopy and
  ultracold molecular physics

abstract:
  We investigate Born-Oppenheimer breakdown (BOB) effects (beyond the usual
mass scaling) for the electronic ground states of a series of homonuclear and
heteronuclear alkali-metal diatoms, together with the Sr$_2$ and Yb$_2$
diatomics. Several widely available electronic structure software packages are
used to calculate the leading contributions to the total isotope shift for
commonly occurring isotopologs of each species. Computed quantities include
diagonal Born-Oppenheimer corrections (mass shifts) and isotopic field shifts.
Mass shifts dominate for light nuclei up to and including K, but field shifts
contribute significantly for Rb and Sr and are dominant for Yb. We compare the
{\em ab initio} mass-shift functions for Li$_2$, LiK and LiRb with
spectroscopically derived ground-state BOB functions from the literature. We
find good agreement in the values of the functions for LiK and LiRb at their
equilibrium geometries, but significant disagreement with the shapes of the
functions for all 3 systems. The differences may be due to contributions of
nonadiabatic terms to the empirical BOB functions. We present a semiclassical
model for the effect of BOB corrections on the binding energies of
near-threshold states and the positions of zero-energy Feshbach resonances.


title:
Spin and charge thermopower effects in the ferromagnetic graphene
  junction

abstract:
  Using wave function matching approach and employing the Landauer-Buttiker
formula a ferromagnetic graphene junction with a temperature gradient across
the system, is studied. We calculate the thermally induced charge and spin
current as well as the thermoelectric voltage (Seebeck effect) in the linear
and nonlinear regimes. Our calculation revealed that due to the electron-hole
symmetry, the charge Seebeck coefficient is, for an undoped magnetic graphene,
an odd function of chemical potential while the spin Seebeck coefficient is an
even function regardless of the temperature gradient and junction length. We
have also found with an accurate tuning external parameter, namely the exchange
filed and gate voltage, the temperature gradient across the junction drives a
pure spin current without accompanying the charge current. Another important
characteristic of thermoelectric transport, thermally induced current in the
nonlinear regime, is examined. It would be our main finding that with
increasing thermal gradient applied to the junction the spin and charge
thermovoltages decrease and even become zero for non-zero temperature bias.


title: Bayesian Sparse Linear Regression with Unknown Symmetric Error

abstract:
  We study full Bayesian procedures for sparse linear regression when errors
have a symmetric but otherwise unknown distribution. The unknown error
distribution is endowed with a symmetrized Dirichlet process mixture of
Gaussians. For the prior on regression coefficients, a mixture of point masses
at zero and continuous distributions is considered. We study behavior of the
posterior with diverging number of predictors. Conditions are provided for
consistency in the mean Hellinger distance. The compatibility and restricted
eigenvalue conditions yield the minimax convergence rate of the regression
coefficients in $\ell_1$- and $\ell_2$-norms, respectively. The convergence
rate is adaptive to both the unknown sparsity level and the unknown symmetric
error density under compatibility conditions. In addition, strong model
selection consistency and a semi-parametric Bernstein-von Mises theorem are
proven under slightly stronger conditions.


title:
Shot Noise of Charge and Spin Current of a Quantum Dot Coupled to
  Semiconductor Electrodes

abstract:
  Based on the scattering matrix theory and non-equilibrium green function
method, we have investigated the fluctuations of charge and spin current of the
systems which consists of a quantum dot (QD) with a resonant level coupled to
two semiconductor contacts within in alternative site $(AS)$ and alternative
bond $(AB)$ framework, where two transverse $(B_x)$ and longitudinal $(B_z)$
magnetic fields are applied to the QD. It is only necessary to use the
auto-correlation function to characterize the fluctuations of charge current
for a two-terminal system because of the relation which is defined as
$\sum_{\alpha}^e S_{\alpha\beta}$ = $\sum_{\beta}^e S_{\alpha\beta}=0$. Our
result shows that both auto-shot noise $(S_{LL})$ and cross-shot noise
$(S_{LR})$ are essential to characterize the fluctuations of spin current when
$B_x$ is present. Moreover, our model calculations show that the sign of the
cross-shot noise of spin current is negative for all surface states of AS/QD/AS
junctions, while it oscillates between positive and negative values for two
surface states of AB/QD/AB junctions as we sweep the gate voltage.


title:
Zero-temperature study of a tetrameric spin-$1/2$ chain in a transverse
  magnetic field

abstract:
  We consider an alternating Heisenberg spin-$1/2$
antiferromagnetic-ferromagnetic ($AF-F$) chain with the space modulated
dominant antiferromagnetic exchange and anisotropic ferromagnetic coupling
(tetrameric spin-$1/2$ chain). The zero-temperature effect of a symmetry
breaking transverse magnetic field on the model is studied numerically. It is
found that the anisotropy effect on the ferromagnetic coupling induces two new
gapped phases. We identified their orderings as a kind of the
stripe-antiferromagnetic phase. As a result, the magnetic phase diagram of the
tetrameric chain shows five gapped quantum phases and the system is
characterized by four critical fields which mark quantum phase transitions in
the ground state of the system with the changing transverse magnetic field. We
have also exploited the well known bipartite entanglement (name as concurrence)
and global entanglement tools to verify the occurrence of quantum phase
transitions and the corresponding critical points.


title: Leveraging Union of Subspace Structure to Improve Constrained Clustering

abstract:
  Many clustering problems in computer vision and other contexts are also
classification problems, where each cluster shares a meaningful label. Subspace
clustering algorithms in particular are often applied to problems that fit this
description, for example with face images or handwritten digits. While it is
straightforward to request human input on these datasets, our goal is to reduce
this input as much as possible. We present a pairwise-constrained clustering
algorithm that actively selects queries based on the union-of-subspaces model.
The central step of the algorithm is in querying points of minimum margin
between estimated subspaces; analogous to classifier margin, these lie near the
decision boundary. We prove that points lying near the intersection of
subspaces are points with low margin. Our procedure can be used after any
subspace clustering algorithm that outputs an affinity matrix. We demonstrate
on several datasets that our algorithm drives the clustering error down
considerably faster than the state-of-the-art active query algorithms on
datasets with subspace structure and is competitive on other datasets.


title: Full rank affine invariant submanifolds

abstract:
  We show that every GL(2, R) orbit closure of translation surfaces is either a
connected component of a stratum, the hyperelliptic locus, or consists entirely
of surfaces whose Jacobians have extra endomorphisms. We use this result to
give applications related to polygonal billiards. For example, we exhibit
infinitely many rational triangles whose unfoldings have dense GL(2,R) orbit.


title: Randomized Matrix Decompositions using R

abstract:
  Matrix decompositions are fundamental tools in the area of applied
mathematics, statistical computing, and machine learning. In particular,
low-rank matrix decompositions are vital, and widely used for data analysis,
dimensionality reduction, and data compression. Massive datasets, however, pose
a computational challenge for traditional algorithms, placing significant
constraints on both memory and processing power. Recently, the powerful concept
of randomness has been introduced as a strategy to ease the computational load.
The essential idea of probabilistic algorithms is to employ some amount of
randomness in order to derive a smaller matrix from a high-dimensional data
matrix. The smaller matrix is then used to compute the desired low-rank
approximation. Such algorithms are shown to be computationally efficient for
approximating matrices with low-rank structure. We present the \proglang{R}
package rsvd, and provide a tutorial introduction to randomized matrix
decompositions. Specifically, randomized routines for the singular value
decomposition, (robust) principal component analysis, interpolative
decomposition, and CUR decomposition are discussed. Several examples
demonstrate the routines, and show the computational advantage over other
methods implemented in R.


title:
Speckle lifetime in XAO coronagraphic images: temporal evolution of
  SPHERE coronagraphic images

abstract:
  The major source of noise in high-contrast imaging is the presence of slowly
evolving speckles that do not average with time. The temporal stability of the
point-spread-function (PSF) is therefore critical to reach a high contrast with
extreme adaptive optics (xAO) instruments. Understanding on which timescales
the PSF evolves and what are the critical parameters driving the speckle
variability allow to design an optimal observing strategy and data reduction
technique to calibrate instrumental aberrations and reveal faint astrophysical
sources. We have obtained a series of 52 min, AO-corrected, coronagraphically
occulted, high-cadence (1.6Hz), H-band images of the star HR 3484 with the
SPHERE (Spectro-Polarimeter High-contrast Exoplanet REsearch instrument on the
VLT. This is a unique data set from an xAO instrument to study its stability on
timescales as short as one second and as long as several tens of minutes. We
find different temporal regimes of decorrelation. We show that residuals from
the atmospheric turbulence induce a fast, partial decorrelation of the PSF over
a few seconds, before a transition to a regime with a linear decorrelation with
time, at a rate of several tens parts per million per second (ppm/s). We
analyze the spatial dependence of this decorrelation, within the well-corrected
radius of the adaptive optics system and show that the linear decorrelation is
faster at short separations. Last, we investigate the influence of the distance
to the meridian on the decorrelation.


title: High current, high efficiency graded band gap perovskite solar cells

abstract:
  Organic-inorganic halide perovskite materials have emerged as attractive
alternatives to conventional solar cell building blocks. Their high light
absorption coefficients and long diffusion lengths suggest high power
conversion efficiencies (PCE),1-5 and indeed perovskite-based single band gap
and tandem solar cell designs have yielded impressive performances.1-16 One
approach to further enhance solar spectrum utilization is the graded band gap,
but this has not been previously achieved for perovskites. In this study, we
demonstrate graded band gap perovskite solar cells with steady-state conversion
efficiencies averaging 18.4%, with a best of 21.7%, all without reflective
coatings. An analysis of the experimental data yields high fill factors of ~75%
and high short circuit current densities up to 42.1 mA/cm2. These cells, which
are based on a novel architecture of two perovskite layers (MASnI3 and
MAPbI3-xBrx), incorporating GaN, monolayer hexagonal boron nitride, and
graphene aerogel, display the highest efficiency ever reported for perovskite
solar cells.


title: Unbounded absolute weak convergence in Banach lattices

abstract:
  Several recent papers investigated unbounded versions of order and norm
convergences in Banach lattices. In this paper, we study the unbounded variant
of weak convergence and its relationship with other convergences. In
particular, we characterize order continuous Banach lattices and reflexive
Banach lattices in terms of this convergence.


title: Homogeneous solutions of extremal Pucci's equations in planar cones

abstract:
  We derive explicit expressions of the homogeneous solutions in two
dimensional cones for Pucci's extremal equations. As examples of possible
applications, we obtain monotonicity formulas for all nonnegative
supersolutions and necessary and sufficient explicit conditions for
non--existence results of Liouville type.


title:
OCR of historical printings with an application to building diachronic
  corpora: A case study using the RIDGES herbal corpus

abstract:
  This article describes the results of a case study that applies Neural
Network-based Optical Character Recognition (OCR) to scanned images of books
printed between 1487 and 1870 by training the OCR engine OCRopus
[@breuel2013high] on the RIDGES herbal text corpus [@OdebrechtEtAlSubmitted].
Training specific OCR models was possible because the necessary *ground truth*
is available as error-corrected diplomatic transcriptions. The OCR results have
been evaluated for accuracy against the ground truth of unseen test sets.
Character and word accuracies (percentage of correctly recognized items) for
the resulting machine-readable texts of individual documents range from 94% to
more than 99% (character level) and from 76% to 97% (word level). This includes
the earliest printed books, which were thought to be inaccessible by OCR
methods until recently. Furthermore, OCR models trained on one part of the
corpus consisting of books with different printing dates and different typesets
*(mixed models)* have been tested for their predictive power on the books from
the other part containing yet other fonts, mostly yielding character accuracies
well above 90%. It therefore seems possible to construct generalized models
trained on a range of fonts that can be applied to a wide variety of historical
printings still giving good results. A moderate postcorrection effort of some
pages will then enable the training of individual models with even better
accuracies. Using this method, diachronic corpora including early printings can
be constructed much faster and cheaper than by manual transcription. The OCR
methods reported here open up the possibility of transforming our printed
textual cultural heritage into electronic text by largely automatic means,
which is a prerequisite for the mass conversion of scanned books.


title:
A characterization of domination weak bicritical graphs with large
  diameter

abstract:
  The domination number of a graph $G$, denoted by $\gamma (G)$, is the minimum
cardinality of a dominating set of $G$. A vertex of a graph is called critical
if its deletion decreases the domination number, and a graph is called critical
if its all vertices are critical. A graph $G$ is called weak bicritical if for
every non-critical vertex $x\in V(G)$, $G-x$ is a critical graph with $\gamma
(G-x)=\gamma (G)$. In this paper, we characterize the connected weak bicritical
graphs $G$ whose diameter is exactly $2\gamma (G)-2$. This is a generalization
of some known results concerning the diameter of graphs with a
domination-criticality.


title: Iteration and the Minimal Resultant

abstract:
  Let $K$ be an algebraically closed field that is complete with respect to a
non-Archimedean absolute value, and let $\varphi\in K(z)$ have degree $d\geq
2$. We characterize maps for which the minimal resultant of an iterate
$\varphi^n$ is given by a simple formula in terms of $d$, $n$, and the minimal
resultant of $\varphi$. We show that such maps are precisely those with
reduction outside of an indeterminacy locus $I(d)$ and which also have
semi-stable reduction for every iterate $\varphi^n$. We give two equivalent
ways of describing such maps, one measure theoretic and the other in terms of
the moduli space $\mathcal{M}_d$ of degree $d$ rational maps.
  As an application, we are able to give an explicit formula for the minimal
value of the diagonal Arakelov-Green's function of a map satisfying the
conditions of the main theorem. We illustrate our results with some explicit
calculations in the case of the Latt\`es maps.


title: Stability of Catenoids and Helicoids in Hyperbolic Space

abstract:
  In this paper, we study the stability of catenoids and helicoids in the
hyperbolic $3$-space $\mathbb{H}^3$.
  (1) For a family of spherical minimal catenoids $\{\mathcal{C}_a\}_{a>0}$ in
$\mathbb{H}^3$, there exist two constants $0<a_c<a_l$ such that
  $\bullet$ $\mathcal{C}_a$ is an unstable minimal surface with index one if
$a<a_c$,
  $\bullet$ $\mathcal{C}_a$ is a globally stable minimal surface if
$a\geq{}a_c$, and
  $\bullet$ $\mathcal{C}_a$ is a least area minimal surface in the sense of
Meeks and Yau if $a\geq{}a_l$.
  (2) For a family of minimal helicoids
$\{\mathcal{H}_{\bar{a}}\}_{\bar{a}\geq{}0}$ in $\mathbb{H}^3$, there exists a
constant $\bar{a}_c=\coth(a_c)$ such that
  $\bullet$ $\mathcal{H}_{\bar{a}}$ is a globally stable minimal surface if
$0\leq\bar{a}\leq\bar{a}_c$, and
  $\bullet$ $\mathcal{H}_{\bar{a}}$ is an unstable minimal surface with index
infinity if $\bar{a}>\bar{a}_c$.


title:
Classification and equivariant cohomology of circle actions on 3d
  manifolds

abstract:
  The classification of Seifert manifolds was given in terms of numeric data by
Seifert in 1933, and then generalized by Orlik and Raymond in 1968 to circle
actions on closed 3d manifolds. In this paper, we further generalize the
classification to circle actions on 3d manifolds with boundaries by adding a
numeric parameter and a union of cycle graphs. Then we describe the equivariant
cohomology of 3d manifolds with circle actions in terms of ring, module and
vector-space structures. We also compute equivariant Betti numbers and
Poincar\'{e} series for these manifolds and discuss the equivariant formality


title: Deep Survival Analysis

abstract:
  The electronic health record (EHR) provides an unprecedented opportunity to
build actionable tools to support physicians at the point of care. In this
paper, we investigate survival analysis in the context of EHR data. We
introduce deep survival analysis, a hierarchical generative approach to
survival analysis. It departs from previous approaches in two primary ways: (1)
all observations, including covariates, are modeled jointly conditioned on a
rich latent structure; and (2) the observations are aligned by their failure
time, rather than by an arbitrary time zero as in traditional survival
analysis. Further, it (3) scalably handles heterogeneous (continuous and
discrete) data types that occur in the EHR. We validate deep survival analysis
model by stratifying patients according to risk of developing coronary heart
disease (CHD). Specifically, we study a dataset of 313,000 patients
corresponding to 5.5 million months of observations. When compared to the
clinically validated Framingham CHD risk score, deep survival analysis is
significantly superior in stratifying patients according to their risk.


title: Golden Probe of Electroweak Symmetry Breaking

abstract:
  The ratio of the Higgs couplings to $WW$ and $ZZ$ pairs, $\lambda_{WZ}$, is a
fundamental parameter in electroweak symmetry breaking as well as a measure of
the (approximate) custodial symmetry possessed by the gauge boson mass matrix.
We show that Higgs decays to four leptons are sensitive, via tree level/1-loop
interference effects, to both the magnitude and, in particular, overall sign of
$\lambda_{WZ}$. Determining this sign requires interference effects, as it is
nearly impossible to measure with rate information. Furthermore, simply
determining the sign effectively establishes the custodial representation of
the Higgs boson. We find that $h\to4\ell$ ($4\ell \equiv 2e2\mu, 4e, 4\mu$)
decays have excellent prospects of directly establishing the overall sign at a
high luminosity 13 TeV LHC. We also examine the ultimate LHC sensitivity in
$h\to4\ell$ to the magnitude of $\lambda_{WZ}$. Our results are independent of
other measurements of the Higgs boson couplings and, in particular, largely
free of assumptions about the top quark Yukawa couplings which also enter at
1-loop. This makes $h\to4\ell$ a unique and independent probe of the
electroweak symmetry breaking mechanism and custodial symmetry.


title: Chandra Observes the End of an Era SN 1987A

abstract:
  Updated imaging and photometric results from Chandra observations of SN
1987A, covering the last 16 years, are presented. We find that the 0.5-2 keV
light curve has remained constant at ~8x10^-12 erg s^-1 cm^-2 since 9500 days,
with the 3-8 keV light curve continuing to increase until at least 10000 days.
The expansion rate of the ring is found to be energy dependent, such that after
day 6000 the ring expands faster in the 2-10 keV band than it does at energies
<2 keV. Images show a reversal of the east-west asymmetry between 7000 and 8000
days after the explosion. The latest images suggest the southeastern side of
the equatorial ring is beginning to fade. Consistent with the latest optical
and infrared results, our Chandra analysis indicates the blast wave is now
leaving the dense equatorial ring, which marks the beginning of a major change
in the evolutionary phase of the supernova remnant 1987A.


title: Joint distributions of partial and global maxima of a Brownian Bridge

abstract:
  We analyze the joint distributions and temporal correlations between the
partial maximum $m$ and the global maximum $M$ achieved by a Brownian Bridge on
the subinterval $[0,t_1]$ and on the entire interval $[0,t]$, respectively. We
determine three probability distribution functions: The joint distribution
$P(m,M)$ of both maxima; the distribution $P(m)$ of the partial maximum; and
the distribution $\Pi(G)$ of the gap between the maxima, $G = M-m$. We present
exact results for the moments of these distributions and quantify the temporal
correlations between $m$ and $M$ by calculating the Pearson correlation
coefficient.

categories: cond-mat.stat-mech math.PR math.ST stat.TH


title: Curvaton scenarios with inflaton decays into curvatons

abstract:
  We consider the possible decay of the inflaton into curvaton particles during
reheating and analyse its effect on curvaton scenarios. Typical decay curvatons
are initially relativistic then become non-relativistic, changing the
background history of the Universe. We show that this change to the background
is the only way in which observational predictions of the scenario are
modified. Moreover, once the required amplitude of perturbations is fixed by
observation there are no signatures of such decays in other cosmological
observables. The decay curvatons can prevent the Universe from becoming
dominated by the curvaton condensate, making it impossible to match
observations in parts of parameter space. This constrains the branching ratio
of the inflaton to curvaton to be less than of order $0.1$ typically. If the
branching ratio is below about $10^{-4}$ it has negligible impact on the model
parameter space and can be ignored.


title: The disturbance of a millisecond pulsar magnetosphere

abstract:
  Pulsar timing has enabled some of the strongest tests of fundamental physics.
Central to the technique is the assumption that the detected radio pulses can
be used to accurately measure the rotation of the pulsar. Here we report on a
broad-band variation in the pulse profile of the millisecond pulsar J1643-1224.
A new component of emission suddenly appears in the pulse profile, decays over
4 months, and results in a permanently modified pulse shape. Profile variations
such as these may be the origin of timing noise observed in other millisecond
pulsars. The sensitivity of pulsar-timing observations to gravitational
radiation can be increased by accounting for this variability.


title: Adapting Deep Network Features to Capture Psychological Representations

abstract:
  Deep neural networks have become increasingly successful at solving classic
perception problems such as object recognition, semantic segmentation, and
scene understanding, often reaching or surpassing human-level accuracy. This
success is due in part to the ability of DNNs to learn useful representations
of high-dimensional inputs, a problem that humans must also solve. We examine
the relationship between the representations learned by these networks and
human psychological representations recovered from similarity judgments. We
find that deep features learned in service of object classification account for
a significant amount of the variance in human similarity judgments for a set of
animal images. However, these features do not capture some qualitative
distinctions that are a key part of human representations. To remedy this, we
develop a method for adapting deep features to align with human similarity
judgments, resulting in image representations that can potentially be used to
extend the scope of psychological experiments.


title: ShapeFit and ShapeKick for Robust, Scalable Structure from Motion

abstract:
  We introduce a new method for location recovery from pair-wise directions
that leverages an efficient convex program that comes with exact recovery
guarantees, even in the presence of adversarial outliers. When pairwise
directions represent scaled relative positions between pairs of views
(estimated for instance with epipolar geometry) our method can be used for
location recovery, that is the determination of relative pose up to a single
unknown scale. For this task, our method yields performance comparable to the
state-of-the-art with an order of magnitude speed-up. Our proposed numerical
framework is flexible in that it accommodates other approaches to location
recovery and can be used to speed up other methods. These properties are
demonstrated by extensively testing against state-of-the-art methods for
location recovery on 13 large, irregular collections of images of real scenes
in addition to simulated data with ground truth.


title: Analysis of time series and signals using the Square Wave Method

abstract:
  The Square Wave Method (SWM), previously introduced for the analysis of
signals and images, is presented here as a mathematical tool suitable for the
analysis of time series and signals. To show the potential that the SWM has to
analyze many different types of time series, the results of the analysis of a
time series composed of a sequence of 10,000 numerical values are presented
here. These values were generated by using the Mathematical Random Number
Generator (MRNG).


title: Review of the three candidate hohlraums in ICF

abstract:
  In this paper, we give a review of three hohlraum geometries, including
cylindrical, octahedral and six-cylinder-port hohlraums, in inertial
confinement fusion (ICF) mainly from theoretical side. Every hohlraum has its
own strengths and weaknesses. Although there is a problem of drive asymmetry in
the cylindrical hohlraums due to some non-ideal factors, the success of
ignition is still possible if more laser energy is available beyond the US
National Ignition Facility (NIF) in the future. Octahedral hohlraums can
provide the high symmetry flux on capsule. However, octahedral hohlraums suffer
from several problems due to the complicated three-dimensional plasma
conditions inside. And up to now, there is no one target design with the
octahedral hohlraums in which each problem can be solved at the same time.
Six-cylinder-port hohlraums combine the merits in theory of both cylindrical
and octahedral hohlraums to a certain extent. We introduce a target design with
good performance by using the six-cylinder-port hohlraums, in which the key
issues of concern, such as laser energy, drive symmetry, and laser plasma
interaction (LPI), etc, are all balanced.


title: Quantum Zeno effect in a nitrogen-vacancy center embedded in a spin bath

abstract:
  We study the longitudinal relaxation of a nitrogen-vacancy (NV) center
surrounded by a $^{13}$C nuclear spin bath in diamond. By means of
cluster-correlation expansion (CCE), we numerically demonstrate the decay
process of electronic state induced by cross relaxation at low temperature. It
is shown that the CCE method is not only capable of describing pure-dephasing
effect at large-detuning regime, but it can also simulate the quantum dynamics
of populations in the nearly resonant regime. We present a proposal to slow
down the decay of NV center via implementing quantum Zeno effect (QZE). The
numerical result shows that QZE can effectively inhibit the decay of NV center.


title: A Family of Reversible BCH Codes

abstract:
  Cyclic codes are an interesting class of linear codes due to their efficient
encoding and decoding algorithms as well as their theoretical importance. BCH
codes form a subclass of cyclic codes and are very important in both theory and
practice as they have good error-correcting capability and are widely used in
communication systems, storage devices and consumer electronics. However, the
dimension and minimum distance of BCH codes are not known in general. The
objective of this paper is to study the dimension and minimum distance of a
family of BCH codes over finite fields, i.e., a class of reversible BCH codes.


title: LCD Cyclic Codes over Finite Fields

abstract:
  In addition to their applications in data storage, communications systems,
and consumer electronics, LCD codes -- a class of linear codes -- have been
employed in cryptography recently. LCD cyclic codes were referred to as
reversible cyclic codes in the literature. The objective of this paper is to
construct several families of reversible cyclic codes over finite fields and
analyse their parameters. The LCD cyclic codes presented in this paper have
very good parameters in general, and contain many optimal codes. A well rounded
treatment of reversible cyclic codes is also given in this paper.


title:
True Rigidity: Interpenetration-free Multi-Body Simulation with
  Polytopic Contact

abstract:
  An effective paradigm for simulating the dynamics of robots that locomote and
manipulate is multi-rigid body simulation with rigid contact. This paradigm
provides reasonable tradeoffs between accuracy, running time, and simplicity of
parameter selection and identification. The Stewart-Trinkle/Anitescu-Potra time
stepping approach is the basis of many existing implementations. It
successfully treats inconsistent (Painleve-type) contact configurations,
efficiently handles many contact events occurring in short time intervals, and
provably converges to the solution of the continuous time differential
algebraic equations (DAEs) as the integration step size tends to zero. However,
there is currently no means to determine when the solution has largely
converged, i.e., when smaller integration steps would result in only small
increases in accuracy.
  The present work describes an approach that computes the event times (when
the set of active equations in a DAE changes) of all contact/impact events for
a multi-body simulation, toward using integration techniques with error control
to compute a solution with desired accuracy.
  We also describe a first-order, variable integration approach that ensures
that rigid bodies with convex polytopic geometries never interpenetrate. This
approach permits taking large steps when possible and takes small steps when
contact is complex.


title: The underlying driver for the \civ Baldwin effect in QSOs with $0<z<5$

abstract:
  Broad emission lines is a prominent property of type I quasi-stellar objects
(QSOs). The origin of the Baldwin effect for \civ $\lambda1549~$\AA\ broad
emission lines, i.e., the luminosity dependence of the \civ equivalent width
(EW), is not clearly established. Using a sample of 87 low-$z$ Palomar-Green
(PG) QSOs and 126 high-$z$ QSOs across the widest possible ranges of redshift
($0<z<5$), we consistently calculate \hb-based single-epoch supermassive black
hole (SMBH) mass and the Eddington ratio to investigate the underlying driver
of the \civ Baldwin effect. An empirical formula to estimate the host fraction
in the continuum luminosity at 5100 \AA\ is presented and used in \hb-based
\mbh calculation for low-$z$ PG QSOs. It is found that, for low-$z$ PG QSOs,
the Eddington ratio has strong correlations with PC1 and PC2 from the principal
component analysis, and \civ EW has a strong correlation with the optical \feii
strength or PC1. Expanding the luminosity range with high-$z$ QSOs, it is found
that \civ Baldwin effect exists in our QSOs sample. Using \hb-based
single-epoch SMBH mass for our QSOs sample, it is found that \civ EW has a
strong correlation with the Eddington ratio, which is stronger than that with
the SMBH mass. It implies that the Eddington ratio seems to be a better
underlying parameter than the SMBH mass to drive the \civ Baldwin effect.


title:
Elliptic flow as a probe for $\psi(2S)$ production mechanism in
  relativistic heavy ion collisions

abstract:
  I discuss the elliptic flows of $\psi(2S)$ with different production
mechanisms in $\sqrt{s_{NN}}=2.76$ TeV Pb-Pb collisions. If the final
$\psi(2S)$s are mainly from the recombination of uncorrelated charm and
anticharm quarks at $T\approx T_c$, charm and anticharm quarks will carry large
collective flows of the bulk medium, which will be inherited by the regenerated
$\psi(2S)$s. This indicates a larger elliptic flow of $\psi(2S)$ than that of
$J/\psi$ which can be regenerated at $T\ge T_c$, $v_2^{\psi(2S)}>v_2^{J/\psi}$.
However, if the final $\psi(2S)$s are mainly from the transitions of
$J/\psi\rightarrow \psi(2S)$ caused by the color screening of QGP, its elliptic
flow should be close to the elliptic flow of $J/\psi$, $v_2^{\psi(2S)}\sim
v_2^{J/\psi}$. Therefore, $\psi(2S)$ elliptic flow is a sensitive probe for its
production mechanisms in relativistic heavy ion collisions.


title:
Constraint on the abundance of primordial black holes in dark matter
  from Planck data

abstract:
  We use Planck data released in 2015 to constrain the abundance of primordial
black holes (PBHs) in dark matter in two different reionization models (one is
the instantaneous reionization and the other is the asymmetric reionization),
and significantly improve the upper limits on the abundance of PBHs from WMAP
3-year data by around two orders of magnitude. Furthermore, these new limits
imply that the event rates of mergers of PBH binaries (Gpc$^{-3}$ yr$^{-1}$)
are less than $0.002$ for $M_\text{pbh}=30M_\odot$, $5$ for
$M_\text{pbh}=10M_\odot$ and $2000$ for $M_\text{pbh}=2M_\odot$ at $95\%$
confidence level (C.L.), and thus GW150914 seems very unlikely produced by the
merger of a PBH binary.


title: Precise large deviations of the first passage time

abstract:
  Let $S_n$ be partial sums of an i.i.d. sequence $\{X_i\}$. We assume that
$\mathbb{E} X_1 <0$ and $\mathbb{P}[X_1>0]>0$. In this paper we study the first
passage time $$ \tau_u = \inf\{n:\; S_n > u\}. $$ The classical Cram\'er's
estimate of the ruin probability says that $$ \mathbb{P}[\tau_u<\infty] \sim C
e^{-\alpha_0 u}\quad \text{as } u\to \infty, $$ for some parameter $\alpha_0$.
The aim of the paper is to describe precise large deviations of the first
crossing by $S_n$ a linear boundary, more precisely for a fixed parameter
$\rho$ we study asymptotic behavior of $\mathbb{P}\left[\tau_u = \lfloor
u/\rho\rfloor \right]$ as $u$ tends to infinity.


title:
Strong decays of the charmed mesons $D_1^*(2680)$, $D^*_3(2760)$,
  $D_2^*(3000)$

abstract:
  In this article, we assign the higher charmed mesons $D^*_1(2680)$,
$D_3^*(2760)$ and $D_2^*(3000)$ to be the 2S $1^-$, 1D $3^-$ and 1F $2^+$
states, respectively, and study the two-body strong decays to the ground state
charmed mesons and light pseudoscalar mesons with the heavy meson effective
theory. We obtain the ratios among the strong decays, which can be confronted
to the experimental data in the future and shed light on the nature of those
higher charmed mesons.


title: Index Divisibility in Dynamical Sequences and Cyclic Orbits Modulo $p$

abstract:
  Let $\phi(x) = x^d + c$ be an integral polynomial of degree at least 2, and
consider the sequence $(\phi^n(0))_{n=0}^\infty$, which is the orbit of $0$
under iteration by $\phi$. Let $D_{d,c}$ denote the set of positive integers
$n$ for which $n \mid \phi^n(0)$. We give a characterization of $D_{d,c}$ in
terms of a directed graph and describe a number of its properties, including
its cardinality and the primes contained therein. In particular, we study the
question of which primes $p$ have the property that the orbit of $0$ is a
single $p$-cycle modulo $p$. We show that the set of such primes is finite when
$d$ is even, and conjecture that it is infinite when $d$ is odd.


title:
Numerical simulation of breathers interactions in two-dimensional O(3)
  nonlinear sigma model

abstract:
  By numerical simulation methods the interactions of oscillating solutions
(breathers) of the (2+1)-dimensional O(3) nonlinear sigma model is
investigated. The models of head-on collisions in which the interacting
breathers, in particular, are combined into a single oscillating soliton, the
reflections from each other and pass through each other are obtained.


title: Exact Partition Function for the Random Walk of an Electrostatic Field

abstract:
  The partition function for the random walk of an electrostatic field produced
by several static parallel infinite charged planes in which the charge
distribution could be either $\pm\sigma$ is obtained. We find the electrostatic
energy of the system and show that it can be analyzed through generalized Dyck
paths. The relation between the electrostatic field and generalized Dyck paths
allows us to sum over all possible electrostatic field configurations and is
used for obtaining the partition function of the system. We illustrate our
results with one example.


title: Interfacial mechanisms for stability of surfactant-laden films

abstract:
  Thin liquid films are central to everyday life. They are ubiquitous in modern
technology (pharmaceuticals, coatings), consumer products (foams, emulsions)
and also serve vital biological functions (tear film of the eye, pulmonary
surfactants in the lung). A common feature in all these examples is the
presence of surface-active molecules at the air-liquid interface. Though they
form only molecularly-thin layers, these surfactants produce complex surface
stresses on the free surface, which have important consequences for the
dynamics and stability of the underlying thin liquid film. Here we conduct
simple thinning experiments to explore the fundamental mechanisms that allow
the surfactant molecules to slow the gravity-driven drainage of the underlying
film. We present a simple model that works for both soluble and insoluble
surfactant systems. We show that surfactants with finite surface rheology
influence bulk flow through viscoelastic interfacial stresses, while
surfactants with inviscid surfaces achieve stability through opposing
surface-tension induced Marangoni flows.


title: Greatest lower bounds on Ricci curvature of homogeneous toric bundles

abstract:
  For Fano homogeneous toric bundles, we obtain a formula of the greatest lower
bound on Ricci curvature. We also give a criteria for the ampleness of a kind
of line bundles over general homogeneous toric bundles.


title: On the duality of c-fusion frames in Hilbert spaces

abstract:
  Improving and extending the concept of dual for frames, fusion frames and
continuous frames, the notion of dual for continuous fusion frames in Hilbert
spaces will be studied. It will be shown that generally the dual of c-fusion
frames may not be defined. To overcome this problem, the new concept namely
Q-dual for c-fusion frames will be defined and some of its properties will be
investigated.


title:
Multiview Cauchy Estimator Feature Embedding for Depth and Inertial
  Sensor-Based Human Action Recognition

abstract:
  The ever-growing popularity of Kinect and inertial sensors has prompted
intensive research efforts on human action recognition. Since human actions can
be characterized by multiple feature representations extracted from Kinect and
inertial sensors, multiview features must be encoded into a unified space
optimal for human action recognition. In this paper, we propose a new
unsupervised feature fusion method termed Multiview Cauchy Estimator Feature
Embedding (MCEFE) for human action recognition. By minimizing empirical risk,
MCEFE integrates the encoded complementary information in multiple views to
find the unified data representation and the projection matrices. To enhance
robustness to outliers, the Cauchy estimator is imposed on the reconstruction
error. Furthermore, ensemble manifold regularization is enforced on the
projection matrices to encode the correlations between different views and
avoid overfitting. Experiments are conducted on the new Chinese Academy of
Sciences - Yunnan University - Multimodal Human Action Database (CAS-YNU-MHAD)
to demonstrate the effectiveness and robustness of MCEFE for human action
recognition.


title: Asymptotic Quantum Algorithm for the Toeplitz Systems

abstract:
  Solving the Toeplitz systems, which is to find the vector $x$ such that $T_nx
= b$ given an $n\times n$ Toeplitz matrix $T_n$ and a vector $b$, has a variety
of applications in mathematics and engineering. In this paper, we present a
quantum algorithm for solving the linear equations of Toeplitz matrices, in
which the Toeplitz matrices are generated by discretizing a continuous
function. It is shown that our algorithm's complexity is nearly
$O(\kappa\textrm{log}^2 n)$, where $\kappa$ and $n$ are the condition number
and the dimension of $T_n$ respectively. This implies our algorithm is
exponentially faster than the best classical algorithm for the same problem if
$\kappa=O(\textrm{poly}(\textrm{log}\,n))$. Since no assumption on the
sparseness of $T_n$ is demanded in our algorithm, it can serve as an example of
quantum algorithms for solving non-sparse linear systems.


title: Half dimensional collapse of ends of manifolds of nonpositive curvature

abstract:
  This paper accomplishes two things. First, we construct a geometric analog of
the rational Tits building for general noncompact, complete, finite volume
$n$-manifolds $M$ of bounded nonpositive curvature. Second, we prove that this
analog has dimension less than $\lfloor n/2\rfloor$.


title: Photons, phonons, and plasmons with orbital angular momentum in plasmas

abstract:
  Exact eigen modes with orbital angular momentum (OAM) in the complex media of
unmagnetized homogeneous plasma are studied. Three exact eigen modes with OAM
are discovered, i.e., photons, phonons, and plasmons. It is found that an OAM
photon can be excited by two familiar Bessel modes without OAM. For the phonons
and plasmons, their OAM are carried by the electrons and ions. The OAM modes in
plasmas and their characteristics can be explored for various potential
applications in plasma physics and accelerator physics.


title:
The African Very Long Baseline Interferometry Network:The Ghana Antenna
  Conversion

abstract:
  The African Very Long Baseline Interferometry Network (AVN) is a pan-African
project that will develop Very Long Baseline Interferometry (VLBI) observing
capability in several countries across the African continent, either by
conversion of existing telecommunications antennas into radio telescopes, or by
building new ones. This paper focuses on the conversion of the Nkutunse
satellite communication station (near Accra, Ghana), specifically the early
mechanical and infrastructure upgrades, together with the development of a
custom ambient receiver and digital backend. The paper concludes with what
remains to be done, before the station can be commissioned as an operational
VLBI station.


title:
Convergence of the finite difference scheme for a general class of the
  spatial segregation of reaction-diffusion systems

abstract:
  In this work we prove convergence of the finite difference scheme for
equations of stationary states of a general class of the spatial segregation of
reaction-diffusion systems with $m\geq 2$ components. More precisely, we show
that the numerical solution $u_h^l$, given by the difference scheme, converges
to the $l^{th}$ component $u_l,$ when the mesh size $h$ tends to zero, provided
$u_l\in C^2(\Omega),$ for every $l=1,2,\dots,m.$ In particular, our proof
provides convergence of a difference scheme for the multi-phase obstacle
problem.


title: An electrically driven spin qubit based on valley mixing

abstract:
  The electrical control of single spin qubits based on semiconductor quantum
dots is of great interest for scalable quantum computing since electric fields
provide an alternative mechanism for qubit control compared with magnetic
fields and can also be easier to produce. Here we outline the mechanism for a
drastic enhancement in the electrically-driven spin rotation frequency for
silicon quantum dot qubits in the presence of a step at a hetero-interface. The
enhancement is due to the strong coupling between the ground and excited states
which occurs when the electron wave-function overcomes the potential barrier
induced by the interface step. We theoretically calculate single qubit gate
times of 170ns for a quantum dot confined at a silicon/silicon-dioxide
interface. The engineering of such steps could be used to achieve fast
electrical rotation and entanglement of spin qubits despite the weak spin-orbit
coupling in silicon.


title:
FCC Based Lepton-Hadron and Photon-Hadron Colliders: Luminosity and
  Physics

abstract:
  Construction of future electron-positron colliders (or dedicated electron
linac) and muon colliders (or dedicated muon ring) tangential to Future
Circular Collider (FCC) will give opportunity to utilize highest energy proton
and nucleus beams for lepton-hadron and photon-hadron collisions. Luminosity
values of FCC based ep, \mup, eA, \muA, \gammap and \gammaA colliders are
estimated. Multi-TeV center of mass energy ep colliders based on the FCC and
linear colliders (LC) are considered in detail. Parameters of upgraded versions
of the FCC proton beam are determined to optimize luminosity of electron-proton
collisions keeping beam-beam effects in mind. Numerical calculations are
performed using a currently being developed collision point simulator. It is
shown that L_{ep}\sim10^{32}\,cm^{-2}s^{-1} can be achieved with LHeC-like
upgrade of the FCC parameters.


title:
Bound-Based Power Optimization for Multi-Hop Heterogeneous Wireless
  Industrial Networks Under Statistical Delay Constraints

abstract:
  The noticeably increased deployment of wireless networks for battery-limited
industrial applications in recent years highlights the need for tractable
performance analysis methodologies as well as efficient QoS-aware transmit
power management schemes. In this work, we seek to combine several important
aspects of such networks, i.e., multi-hop connectivity, channel heterogeneity
and the queuing effect, in order to address these needs. We design
delay-bound-based algorithms for transmit power minimization and network
lifetime maximization of multi-hop heterogeneous wireless networks using our
previously developed stochastic network calculus approach for performance
analysis of a cascade of buffered wireless fading channels. Our analysis shows
an overall transmit power saving of up to 95% compared to a fixed power
allocation scheme when using a service model in terms of the Shannon capacity
limit. For a more realistic set-up, we evaluate the performance of the
suggested algorithm in a WirelessHART network, which is a widely used
communication standard for process automation and other industrial
applications. We find that link heterogeneity can significantly reduce network
lifetime when no efficient power management is applied. Moreover, we show,
using extensive simulation study, that the proposed bound-based power
allocation performs reasonably well compared to the real optimum, especially in
the case of WirelessHART networks.


title: Playing for Data: Ground Truth from Computer Games

abstract:
  Recent progress in computer vision has been driven by high-capacity models
trained on large datasets. Unfortunately, creating large datasets with
pixel-level labels has been extremely costly due to the amount of human effort
required. In this paper, we present an approach to rapidly creating
pixel-accurate semantic label maps for images extracted from modern computer
games. Although the source code and the internal operation of commercial games
are inaccessible, we show that associations between image patches can be
reconstructed from the communication between the game and the graphics
hardware. This enables rapid propagation of semantic labels within and across
images synthesized by the game, with no access to the source code or the
content. We validate the presented approach by producing dense pixel-level
semantic annotations for 25 thousand images synthesized by a photorealistic
open-world computer game. Experiments on semantic segmentation datasets show
that using the acquired data to supplement real-world images significantly
increases accuracy and that the acquired data enables reducing the amount of
hand-labeled real-world data: models trained with game data and just 1/3 of the
CamVid training set outperform models trained on the complete CamVid training
set.


title:
Spacetimes with Semantics (III) - The Structure of Functional Knowledge
  Representation and Artificial Reasoning

abstract:
  Using the previously developed concepts of semantic spacetime, I explore the
interpretation of knowledge representations, and their structure, as a semantic
system, within the framework of promise theory. By assigning interpretations to
phenomena, from observers to observed, we may approach a simple description of
knowledge-based functional systems, with direct practical utility. The focus is
especially on the interpretation of concepts, associative knowledge, and
context awareness. The inference seems to be that most if not all of these
concepts emerge from purely semantic spacetime properties, which opens the
possibility for a more generalized understanding of what constitutes a
learning, or even `intelligent' system.
  Some key principles emerge for effective knowledge representation: 1)
separation of spacetime scales, 2) the recurrence of four irreducible types of
association, by which intent propagates: aggregation, causation, cooperation,
and similarity, 3) the need for discrimination of identities (discrete), which
is assisted by distinguishing timeline simultaneity from sequential events, and
4) the ability to learn (memory). It is at least plausible that emergent
knowledge abstraction capabilities have their origin in basic spacetime
structures.
  These notes present a unified view of mostly well-known results; they allow
us to see information models, knowledge representations, machine learning, and
semantic networking (transport and information base) in a common framework. The
notion of `smart spaces' thus encompasses artificial systems as well as living
systems, across many different scales, e.g. smart cities and organizations.


title:
Logarithmical regularity criteria in terms of pressure for the three
  dimensional nonlinear dissipative system modeling electro-diffusion

abstract:
  In this paper, logarithmically improved regularity criteria for the
Navier--Stokes/Poisson--Nernst--Planck system are established in terms of both
the pressure and the gradient of pressure in the homogeneous Besov space.


title: Automating Political Bias Prediction

abstract:
  Every day media generate large amounts of text. An unbiased view on media
reports requires an understanding of the political bias of media content.
Assistive technology for estimating the political bias of texts can be helpful
in this context. This study proposes a simple statistical learning approach to
predict political bias from text. Standard text features extracted from
speeches and manifestos of political parties are used to predict political bias
in terms of political party affiliation and in terms of political views.
Results indicate that political bias can be predicted with above chance
accuracy. Mistakes of the model can be interpreted with respect to changes of
policies of political actors. Two approaches are presented to make the results
more interpretable: a) discriminative text features are related to the
political orientation of a party and b) sentiment features of texts are
correlated with a measure of political power. Political power appears to be
strongly correlated with positive sentiment of a text. To highlight some
potential use cases a web application shows how the model can be used for texts
for which the political bias is not clear such as news articles.


title: An intelligent classification model for phishing email detection

abstract:
  Phishing attacks are one of the trending cyber attacks that apply socially
engineered messages that are communicated to people from professional hackers
aiming at fooling users to reveal their sensitive information, the most popular
communication channel to those messages is through users emails. This paper
presents an intelligent classification model for detecting phishing emails
using knowledge discovery, data mining and text processing techniques. This
paper introduces the concept of phishing terms weighting which evaluates the
weight of phishing terms in each email. The pre processing phase is enhanced by
applying text stemming and WordNet ontology to enrich the model with word
synonyms. The model applied the knowledge discovery procedures using five
popular classification algorithms and achieved a notable enhancement in
classification accuracy, 0.991 accuracy was achieved using the Random Forest
algorithm and 0.984 using J48, which is to our knowledge the highest accuracy
rate for an accredited data set. This paper also presents a comparative study
with similar proposed classification techniques.


title: A new general family of deterministic hierarchical networks

abstract:
  It is known that many networks modeling real-life complex systems are
small-word (large local clustering and small diameter) and scale-free (power
law of the degree distribution), and very often they are also hierarchical.
Although most of the models are based on stochastic methods, some deterministic
constructions have been recently proposed, because this allows a better
computation of their properties. Here a new deterministic family of
hierarchical networks is presented, which generalizes most of the previous
proposals, such as the so-called binomial tree. The obtained graphs can be seen
as graphs on alphabets (where vertices are labeled with words of a given
alphabet, and the edges are defined by a specific rule relating different
words). This allows us the characterization of their main distance-related
parameters, such as the radius and the diameter. Moreover, as a by product, an
efficient shortest-path local algorithm is proposed.


title: A General Characterization of the Statistical Query Complexity

abstract:
  Statistical query (SQ) algorithms are algorithms that have access to an {\em
SQ oracle} for the input distribution $D$ instead of i.i.d.~ samples from $D$.
Given a query function $\phi:X \rightarrow [-1,1]$, the oracle returns an
estimate of ${\bf E}_{ x\sim D}[\phi(x)]$ within some tolerance $\tau_\phi$
that roughly corresponds to the number of samples.
  In this work we demonstrate that the complexity of solving general problems
over distributions using SQ algorithms can be captured by a relatively simple
notion of statistical dimension that we introduce. SQ algorithms capture a
broad spectrum of algorithmic approaches used in theory and practice, most
notably, convex optimization techniques. Hence our statistical dimension allows
to investigate the power of a variety of algorithmic approaches by analyzing a
single linear-algebraic parameter. Such characterizations were investigated
over the past 20 years in learning theory but prior characterizations are
restricted to the much simpler setting of classification problems relative to a
fixed distribution on the domain (Blum et al., 1994; Bshouty and Feldman, 2002;
Yang, 2001; Simon, 2007; Feldman, 2012; Szorenyi, 2009). Our characterization
is also the first to precisely characterize the necessary tolerance of queries.
We give applications of our techniques to two open problems in learning theory
and to algorithms that are subject to memory and communication constraints.


title:
An EM algorithm for absolutely continuous Marshall-Olkin bivariate
  Pareto distribution with location and scale

abstract:
  Recently \cite{AsimitFurmanVernic:2016} used EM algorithm to estimate
singular Marshall-Olkin bivariate Pareto distribution. We describe
\textbf{absolutely continuous} version of this distribution. We study
estimation of the parameters by EM algorithm both in presence and without
presence of location and scale parameters. Some innovative solutions are
provided for different problems arised during implementation of EM algorithm. A
real-life data analysis is also shown for illustrative purpose.


title: NGC5252: a pair of radio-emitting active galactic nuclei?

abstract:
  The X-ray source CXO J133815.6+043255 has counterparts in the UV, optical,
and radio bands. Based on the multi-band investigations, it has been recently
proposed by Kim et al. (2015) as a rarely-seen off-nucleus ultraluminous X-ray
(ULX) source with a black hole mass of >= 10^4 solar mass in the nearby Seyfert
galaxy NGC 5252. To explore its radio properties at very high angular
resolution, we performed very long-baseline interferometry (VLBI) observations
with the European VLBI Network (EVN) at 1.7 GHz. We find that the radio
counterpart is remarkably compact among the known ULXs. It does not show a
resolved structure with a resolution of a few milliarcsecond (mas), and the
total recovered flux density is comparable to that measured in earlier
sub-arcsecond-resolution images. The compact radio structure, the relatively
flat spectrum, and the high radio luminosity are consistent with a weakly
accreting supermassive black hole in a low-luminosity active galactic nucleus.
The nucleus of NGC 5252 itself has similar radio properties. We argue that the
system represents a relatively rare pair of active galactic nuclei, where both
components emit in the radio.


title: Residual CNDS

abstract:
  Convolutional Neural networks nowadays are of tremendous importance for any
image classification system. One of the most investigated methods to increase
the accuracy of CNN is by increasing the depth of CNN. Increasing the depth by
stacking more layers also increases the difficulty of training besides making
it computationally expensive. Some research found that adding auxiliary forks
after intermediate layers increases the accuracy. Specifying which intermediate
layer shoud have the fork just addressed recently. Where a simple rule were
used to detect the position of intermediate layers that needs the auxiliary
supervision fork. This technique known as convolutional neural networks with
deep supervision (CNDS). This technique enhanced the accuracy of classification
over the straight forward CNN used on the MIT places dataset and ImageNet. In
the other side, Residual Learning is another technique emerged recently to ease
the training of very deep CNN. Residual Learning framwork changed the learning
of layers from unreferenced functions to learning residual function with regard
to the layer's input. Residual Learning achieved state of arts results on
ImageNet 2015 and COCO competitions. In this paper, we study the effect of
adding residual connections to CNDS network. Our experiments results show
increasing of accuracy over using CNDS only.


title:
Photon Spheres and Sonic Horizons in Black Holes from Supergravity and
  Other Theories

abstract:
  We study closed photon orbits in spherically-symmetric static solutions of
supergravity theories, a Horndeski theory, and a theory of quintessence. These
orbits lie in what we shall call a photon sphere (anti-photon sphere) if the
orbit is unstable (stable). We show that in all the asymptotically flat
solutions we examine that admit a regular event horizon, and whose
energy-momentum tensor satisfies the strong energy condition, there is one and
only one photon sphere outside the event horizon. We give an example of a
Horndeski theory black hole (whose energy-momentum tensor violates the strong
energy condition) whose metric admits both a photon sphere and an anti-photon
sphere. The uniqueness and non-existence also holds for asymptotically anti-de
Sitter solutions in gauged supergravity. The latter also exhibit the projective
symmetry that was first discovered for the Schwarzschild-de Sitter metrics: the
unparameterised null geodesics are the same as when the cosmological or gauge
coupling constant vanishes. We also study the closely related problem of
accretion flows by perfect fluids in these metrics. For a radiation fluid,
Bondi's sonic horizon coincides with the photon sphere. For a general
polytropic equation of state this is not the case. Finally we exhibit
counterexamples to a conjecture of Hod's.


title:
Lower semicontinuity of the entropic disturbance and its applications in
  quantum information theory

abstract:
  We prove that for any infinite-dimensional quantum channel the entropic
disturbance (defined as difference between the $\chi$-quantity of a generalized
ensemble and that of the image of the ensemble under the channel) is lower
semicontinuous on the natural set of its definition. We establish a number of
useful corollaries of this property, in particular, we prove the continuity of
the output $\chi\textrm{-}$quantity and the existence of $\chi$-optimal
ensemble for any quantum channel under the energy-type input constraint.


title:
Multidimensional viscosity solutions theory of semi-linear partial
  differential equations

abstract:
  In this study, we concern the multidimensional viscosity solutions theory of
a kind of semi-linear partial differential equations (PDEs). A new definition
of viscosity solution for this multidimensional semi-linear PDEs which is
related to a type of multidimensional backward stochastic differential
equations (BSDEs) is given. Further more, we establish the existence and
uniqueness results for the viscosity solution of this semi-linear PDEs via the
comparison theorem of the related BSDEs and a smooth approximation technique.


title:
Analytic Optimization of a MERA network and its Relevance to Quantum
  Integrability and Wavelet

abstract:
  I present an example of how to analytically optimize a multiscale
entanglement renormalization ansatz for a finite antiferromagnetic Heisenberg
chain. For this purpose, a quantum-circuit representation is taken into
account, and we construct the exactly entangled ground state so that a trivial
IR state is modified sequentially by operating separated entangler layers
(monodromy operators) at each scale. The circuit representation allows us to
make a simple understanding of close relationship between the entanglement
renormalization and quantum integrability. We find that the entangler should
match with the $R$-matrix, not a simple unitary, and also find that the
optimization leads to the mapping between the Bethe roots and the Daubechies
wavelet coefficients.

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


title:
Making soft solids flow: microscopic bursts and conga lines in jammed
  emulsions

abstract:
  It is well known that jammed soft materials will flow if sheared above their
yield stress - think mayonnaise spread on bread - but a complete microscopic
description of this seemingly sim- ple process has yet to emerge. What remains
elusive is a microscopic framework that explains the macroscopic flow, derived
from a 3-D spatially resolved analysis of the dynamics of the droplets or
particles that compose the soft material. By combining confocal-rheology
experiments on compressed emulsions and numerical simulations, we unravel that
the primary microscopic mechanisms for flow are strongly influenced by the rate
of the imposed deformation. When shearing fast, small coordinated clusters of
droplets move collectively as in a conga line, while at low rates the flow
emerges from bursts of droplet rearrangements, correlated over large domains.
These regions exhibit complex spatio-temporal correlation patterns that reflect
the long range elasticity embedded in the jammed material. These results
identify the three-dimensional structure of microscopic rearrangements within
sheared soft solids, revealing that the characteristic shape and dynamics of
these structures are strongly determined by the rate of the external shear.


title: On the Kaehler metrics over ${mathrm{Sym}^{d}(X)$

abstract:
  Let $X$ be a compact connected Riemann surface of genus $g$, with $g \geq 2$.
For each $d <\eta(X)$, where $\eta(X)$ is the gonality of $X$, the symmetric
product $\text{Sym}^d(X)$ embeds into $\text{Pic}^d(X)$ by sending an effective
divisor of degree $d$ to the corresponding holomorphic line bundle. Therefore,
the restriction of the flat K\"ahler metric on $\text{Pic}^d(X)$ is a K\"ahler
metric on $\text{Sym}^d(X)$. We investigate this K\"ahler metric on
$\text{Sym}^d(X)$. In particular, we estimate it's Bergman kernel. We also
prove that any holomorphic automorphism of $\text{Sym}^d(X)$ is an isometry.


title: Continuous Time Random Walks for the Evolution of Lagrangian Velocities

abstract:
  We develop a continuous time random walk (CTRW) approach for the evolution of
Lagrangian velocities in steady heterogeneous flows based on a stochastic
relaxation process for the streamwise particle velocities. This approach
describes persistence of velocities over a characteristic spatial scale, unlike
classical random walk methods, which model persistence over a characteristic
time scale. We first establish the relation between Eulerian and Lagrangian
velocities for both equidistant and isochrone sampling along streamlines, under
transient and stationary conditions. Based on this, we develop a space
continuous CTRW approach for the spatial and temporal dynamics of Lagrangian
velocities. While classical CTRW formulations have non-stationary Lagrangian
velocity statistics, the proposed approach quantifies the evolution of the
Lagrangian velocity statistics under both stationary and non-stationary
conditions. We provide explicit expressions for the Lagrangian velocity
statistics, and determine the behaviors of the mean particle velocity, velocity
covariance and particle dispersion. We find strong Lagrangian correlation and
anomalous dispersion for velocity distributions which are tailed toward low
velocities as well as marked differences depending on the initial conditions.
The developed CTRW approach predicts the Lagrangian particle dynamics from an
arbitrary initial condition based on the Eulerian velocity distribution and a
characteristic correlation scale.


title: Bayesian Learning of Dynamic Multilayer Networks

abstract:
  A plethora of networks is being collected in a growing number of fields,
including disease transmission, international relations, social interactions,
and others. As data streams continue to grow, the complexity associated with
these highly multidimensional connectivity data presents novel challenges. In
this paper, we focus on the time-varying interconnections among a set of actors
in multiple contexts, called layers. Current literature lacks flexible
statistical models for dynamic multilayer networks, which can enhance quality
in inference and prediction by efficiently borrowing information within each
network, across time, and between layers. Motivated by this gap, we develop a
Bayesian nonparametric model leveraging latent space representations. Our
formulation characterizes the edge probabilities as a function of shared and
layer-specific actors positions in a latent space, with these positions
changing in time via Gaussian processes. This representation facilitates
dimensionality reduction and incorporates different sources of information in
the observed data. In addition, we obtain tractable procedures for posterior
computation, inference, and prediction. We provide theoretical results on the
flexibility of our model. Our methods are tested on simulations and infection
studies monitoring dynamic face-to-face contacts among individuals in multiple
days, where we perform better than current methods in inference and prediction.


title: High-Velocity Bipolar Molecular Emission from an AGN Torus

abstract:
  We have detected in ALMA observations CO J = 6 - 5 emission from the nucleus
of the Seyfert galaxy NGC 1068. The low-velocity (up to +/- 70 km/s relative to
systemic) CO emission resolves into a 12x7 pc structure, roughly aligned with
the nuclear radio source. Higher-velocity emission (up to +/- 400 km/s) is
consistent with a bipolar outflow in a direction nearly perpendicular (roughly
80 degrees) to the nuclear disk. The position-velocity diagram shows that in
addition to the outflow, the velocity field may also contain rotation about the
disk axis. These observations provide compelling evidence in support of the
disk-wind scenario for the AGN obscuring torus.


title: Type-1.5 superconductivity in multicomponent systems

abstract:
  In general a superconducting state breaks multiple symmetries and, therefore,
is characterized by several different coherence lengths $\xi_i$, $i=1,...,N$.
Moreover in multiband material even superconducting states that break only a
single symmetry are nonetheless described, under certain conditions by
multi-component theories with multiple coherence lengths. As a result of that
there can appear a state where some coherence lengths are larger and some are
smaller than the magnetic field penetration length $\lambda$: $\xi_1\leq
\xi_2... < \sqrt{2}\lambda<\xi_M\leq...\xi_N$. That state was recently termed
"type-1.5" superconductivity. This breakdown of type-1/type-2 dichotomy is
rather generic near a phase transition between superconducting states with
different symmetries. The examples include the transitions between $U(1)$ and
$U(1)\times U(1)$ states or between $U(1)$ and $U(1)\times Z_2$ states. The
later example is realized in systems that feature transition between s-wave and
$s+is$ states. The extra fundamental length scales have many physical
consequences. In particular in these regimes vortices can attract one another
at long range but repel at shorter ranges. Such a system can form vortex
clusters in low magnetic fields. The vortex clustering in the type-1.5 regime
gives rise to many physical effects, ranging from macroscopic phase separation
in domains of different broken symmetries, to unusual transport properties.