title: A Chernoff bound for branching random walk

abstract:
  Concentration inequalities, which prove to be very useful in a variety of
fields, provide fairly tight bounds for large deviation probability while
central limit theorem (CLT) describes the asymptotic distribution around the
mean (within scope of $\sqrt{n}$ order). Harris (1963) conjectured that for a
supercritical branching random walk (BRW) of i.i.d offspring and iid
displacement, population's positions in $nth$ generation approach to Gaussian
distribution --- central limit theorem. This conjecture was latter proved by
Stam (1966) and Kaplan and Asmussen (1976). Refinements and extensions
followed. Yet little effort is known on large deviation probability for BRW. In
this note, we suggest and verify a more general and probably more formal
setting of BRW. Benefiting from this framework, a Chernoff bound for BRW is
immediately obtained. The relation between RW (random walk) and BRW is
addressed.


title:
Frechet Differentiability in Besov Spaces in the Optimal Control of
  Parabolic Free Boundary Problems

abstract:
  We consider the inverse Stefan type free boundary problem, where information
on the boundary heat flux and density of the sources are missing and must be
found along with the temperature and the free boundary. We pursue optimal
control framework where boundary heat flux, density of sources, and free
boundary are components of the control vector. The optimality criteria consists
of the minimization of the $L_2$-norm declinations of the temperature
measurements at the final moment, phase transition temperature, and final
position of the free boundary. We prove the Frechet differentiability in Besov
spaces, and derive the formula for the Frechet differential under minimal
regularity assumptions on the data. The result implies a necessary condition
for optimal control and opens the way to the application of projective gradient
methods in Besov spaces for the numerical solution of the inverse Stefan
problem.


title:
Trace and extension theorems relating Besov spaces to weighted averaged
  Sobolev spaces

abstract:
  There are known trace and extension theorems relating functions in a weighted
Sobolev space in a domain U to functions in a Besov space on the boundary bU.
We extend these theorems to the case where the Sobolev exponent p is less than
one by modifying our Sobolev spaces to consider averages of functions in
Whitney balls. Averaged Sobolev spaces are also of interest in the applications
in the case where p>1, and so we also provide trace and extension results in
that case. Finally, we provide some comparable results for Neumann traces and
extensions.


title:
Spatial Clustering of Curves with Functional Covariates: A Bayesian
  Partitioning Model with Application to Spectra Radiance in Climate Study

abstract:
  In climate change study, the infrared spectral signatures of climate change
have recently been conceptually adopted, and widely applied to identifying and
attributing atmospheric composition change. We propose a Bayesian hierarchical
model for spatial clustering of the high-dimensional functional data based on
the effects of functional covariates and local features. We couple the
functional mixed-effects model with a generalized spatial partitioning method
for: (1) producing spatially contiguous clusters for the high-dimensional
spatio-functional data; (2) improving the computational efficiency via parallel
computing over subregions or multi-level partitions; and (3) capturing the
near-boundary ambiguity and uncertainty for data-driven partitions. We propose
a generalized partitioning method which puts less constraints on the shape of
spatial clusters. Dimension reduction in the parameter space is also achieved
via Bayesian wavelets to alleviate the increasing model complexity introduced
by clusters. The model well captures the regional effects of the atmospheric
and cloud properties on the spectral radiance measurements. The results
elaborate the importance of exploiting spatially contiguous partitions for
identifying regional effects and small-scale variability.


title:
Using Alloy to Formally Model and Reason About an OpenFlow Network
  Switch

abstract:
  Openflow provides a standard interface for separating a network into a data
plane and a programmatic control plane. This enables easy network
reconfiguration, but introduces the potential for programming bugs to cause
network effects. To study OpenFlow switch behavior, we used Alloy to create a
software abstraction describing the internal state of a network and its
OpenFlow switches. This work is an attempt to model the static and dynamic
behaviour a network built using OpenFlow switches.


title: Distribution Market Clearing and Settlement

abstract:
  There are various undergoing efforts by system operators to set up an
electricity market at the distribution level to enable a rapid and widespread
deployment of distributed energy resources (DERs) and microgrids. This paper
follows the previous work of the authors in implementing the distribution
market operator (DMO) concept, and focuses on investigating the clearing and
settlement processes performed by the DMO. The DMO clears the market to assign
the awarded power from the wholesale market to customers within its service
territory based on their associated demand bids. The DMO accordingly settles
the market to identify the distribution locational marginal prices (DLMPs) and
calculate payments from each customer and the total payment to the system
operator. Numerical simulations exhibit the merits and effectiveness of the
proposed DMO clearing and settlement processes.


title:
Perturbation of well-posedness and layer potentials for higher-order
  elliptic systems with rough coefficients

abstract:
  In this paper we study boundary value problems for higher order elliptic
differential operators in divergence form. We consider the two closely related
topics of inhomogeneous problems and problems with boundary data in fractional
smoothness spaces.
  We establish $L^\infty$ perturbative results concerning well posedness of
inhomogeneous problems with boundary data in fractional smoothness spaces.
  Combined with earlier known results, this allows us to establish new well
posedness results for second order operators whose coefficients are close to
being real and t-independent and for fourth-order operators close to the
biharmonic operator.


title: Non-equilibrium piezo-thermal effect in spinning gas

abstract:
  A spinning gas, heated adiabatically through axial compression, is known to
exhibit a rotation-dependent heat capacity. However, as equilibrium is
approached, a new effect is identified here wherein the temperature does not
grow homogeneously in the radial direction, but develops a temperature
differential with the hottest region on axis, at the maximum of the centrifugal
potential energy. This phenomenon, which we call a piezo-thermal effect, is
shown to grow bilinearly with the compression rate and the amplitude of the
potential. Numerical simulations confirm a simple model of this effect, which
can be generalized to other forms of potential energy and methods of heating.


title: Temperature-dependent optical properties of gold thin films

abstract:
  Understanding the temperature dependence of the optical properties of thin
metal films is critical for designing practical devices for high temperature
applications in a variety of research areas, including plasmonics and
near-field radiative heat transfer. Even though the optical properties of bulk
metals at elevated temperatures have been studied, the temperature-dependent
data for thin metal films, with thicknesses ranging from few tens to few
hundreds of nanometers, is largely missing. In this work we report on the
optical constants of single- and polycrystalline gold thin films at elevated
temperatures in the wavelength range from 370 to 2000 nm. Our results show that
while the real part of the dielectric function changes marginally with
increasing temperature, the imaginary part changes drastically. For
200-nm-thick single- and polycrystalline gold films the imaginary part of the
dielectric function at 500 0C becomes nearly twice larger than that at room
temperature. In contrast, in thinner films (50-nm and 30-nm) the imaginary part
can show either increasing or decreasing behavior within the same temperature
range and eventually at 500 0C it becomes nearly 3-4 times larger than that at
room temperature. The increase in the imaginary part at elevated temperatures
significantly reduces the surface plasmon polariton propagation length and the
quality factor of the localized surface plasmon resonance for a spherical
particle. We provide experiment-fitted models to describe the
temperature-dependent gold dielectric function as a sum of one Drude and two
Critical Point oscillators. These causal analytical models could enable
accurate multiphysics modelling of gold-based nanophotonic and plasmonic
elements in both frequency and time domains.


title: High-performance near- and mid-infrared crystalline coatings

abstract:
  Substrate-transferred crystalline coatings have recently emerged as a
groundbreaking new concept in optical interference coatings. Building upon our
initial demonstration of this technology, we have now realized significant
improvements in the limiting optical performance of these novel single-crystal
$GaAs/Al_{x}Ga_{1-x}As$ multilayers. In the near-infrared (NIR), for coating
center wavelengths spanning 1064 to 1560 nm, we have reduced the excess optical
losses (scatter + absorption) to levels as low as 3 parts per million, enabling
the realization of a cavity finesse exceeding $3\times 10^{5}$ at the
telecom-relevant wavelength range near 1550 nm. Moreover, we demonstrate the
direct measurement of sub-ppm optical absorption at 1064 nm. Concurrently, we
investigate the mid-IR (MIR) properties of these coatings and observe
exceptional performance for first attempts in this important wavelength region.
Specifically, we verify excess losses at the hundred ppm level for wavelengths
of 3300 and 3700 nm. Taken together, our NIR optical losses are now fully
competitive with ion beam sputtered multilayer coatings, while our first
prototype MIR optics have already reached state-of-the-art performance levels
for reflectors covering this portion of the fingerprint region for optical gas
sensing. Mirrors fabricated with our crystalline coating technique exhibit the
lowest mechanical loss, and thus the lowest Brownian noise, the highest thermal
conductivity, and, potentially, the widest spectral coverage of any
"supermirror" technology in a single material platform. Looking ahead, we see a
bright future for crystalline coatings in applications requiring the ultimate
levels of optical, thermal, and optomechanical performance


title:
To Fall Or Not To Fall: A Visual Approach to Physical Stability
  Prediction

abstract:
  Understanding physical phenomena is a key competence that enables humans and
animals to act and interact under uncertain perception in previously unseen
environments containing novel object and their configurations. Developmental
psychology has shown that such skills are acquired by infants from observations
at a very early stage.
  In this paper, we contrast a more traditional approach of taking a
model-based route with explicit 3D representations and physical simulation by
an end-to-end approach that directly predicts stability and related quantities
from appearance. We ask the question if and to what extent and quality such a
skill can directly be acquired in a data-driven way bypassing the need for an
explicit simulation.
  We present a learning-based approach based on simulated data that predicts
stability of towers comprised of wooden blocks under different conditions and
quantities related to the potential fall of the towers. The evaluation is
carried out on synthetic data and compared to human judgments on the same
stimuli.


title: Torsion or not torsion, that is the question

abstract:
  A hypothesis of general relativity is that spacetime torsion vanishes
identically. This assumption has no empirical support; in fact, a nonvanishing
torsion is compatible with all the experimental tests of general relativity.
The first part of this essay specifies the framework that is suitable to test
the vanishing-torsion hypothesis, and an interesting relation with the
gravitational degrees of freedom is suggested. In the second part, some
original empirical tests are proposed based on the observation that torsion
induces new interactions between different spin-polarized particles.


title:
Theory of intervalley Coulomb interactions in monolayer transition-metal
  dichalcogenides

abstract:
  Exciton optical transitions in transition-metal dichalcogenides offer unique
opportunities to study rich many-body physics. Recent experiments in monolayer
WSe$_2$ and WS$_2$ have shown that while the low-temperature photoluminescence
from neutral excitons and three-body complexes is suppressed in the presence of
elevated electron densities or strong photoexcitation, new dominant peaks
emerge in the low-energy side of the spectrum. I present a theory that
elucidates the nature of these optical transitions showing the role of the
intervalley Coulomb interaction. After deriving a compact dynamical form for
the Coulomb potential, I calculate the self-energy of electrons due to their
interaction with this potential. For electrons in the upper valleys of the
spin-split conduction band, the self energy includes a moderate redshift due to
exchange, and most importantly, a correlation-induced virtual state in the
band-gap. The latter sheds light on the origin of the luminescence in monolayer
WSe$_2$ and WS$_2$ in the presence of pronounced many-body interactions.


title: Cross-Frequency Coupling of Neuronal Oscillations During Cognition

abstract:
  How the brain co-ordinates the actions of distant regions in an efficient
manner is an open problem. Many believe that cross-frequency coupling between
the amplitude of high frequency local field potential oscillations in one
region and the phase of lower frequency signals in another may form a possible
mechanism. This work provides a preliminary study from both an experimental and
theoretical viewpoint, concentrating on possible coupling between the
hippocampus and pre-frontal cortex in rats during tasks involving working
memory, spatial navigation and decision making processes. Attempts to search
for such coupling events are made using newly developed MATLAB scripts. This
leads to the discovery of increased envelope-to-signal correlation (ESC)
between the 1-10 Hz hippocampus theta and 30-40 Hz pre-fontal cortex gamma
bands when a choice turn is approached during a T-maze task. From a theoretical
perspective, a standard connectionist modelling approach is extended to allow
for the formation of oscillations. Although detrimental to overall average task
performance, this did lead to a reduced increase in performance variation as
noise was increased, when compared to a standard non-oscillating model.


title: Bulk Comptonization by Turbulence in Accretion Disks

abstract:
  Radiation pressure dominated accretion discs around compact objects may have
turbulent velocities that greatly exceed the electron thermal velocities within
the disc. Bulk Comptonization by the turbulence may therefore dominate over
thermal Comptonization in determining the emergent spectrum. Bulk
Comptonization by divergenceless turbulence is due to radiation viscous
dissipation only. It can be treated as thermal Comptonization by solving the
Kompaneets equation with an equivalent "wave" temperature, which is a weighted
sum over the power present at each scale in the turbulent cascade. Bulk
Comptonization by turbulence with non-zero divergence is due to both pressure
work and radiation viscous dissipation. Pressure work has negligible effect on
photon spectra in the limit of optically thin turbulence, and in this limit
radiation viscous dissipation alone can be treated as thermal Comptonization
with a temperature equivalent to the full turbulent power. In the limit of
extremely optically thick turbulence, radiation viscous dissipation is
suppressed, and the evolution of local photon spectra can be understood in
terms of compression and expansion of the strongly coupled photon and gas
fluids. We discuss the consequences of these effects for self-consistently
resolving and interpreting turbulent Comptonization in spectral calculations in
radiation MHD simulations of high luminosity accretion flows.


title:
Fashionista: A Fashion-aware Graphical System for Exploring Visually
  Similar Items

abstract:
  To build a fashion recommendation system, we need to help users retrieve
fashionable items that are visually similar to a particular query, for reasons
ranging from searching alternatives (i.e., substitutes), to generating stylish
outfits that are visually consistent, among other applications. In domains like
clothing and accessories, such considerations are particularly paramount as the
visual appearance of items is a critical feature that guides users' decisions.
However, existing systems like Amazon and eBay still rely mainly on keyword
search and recommending loosely consistent items (e.g. based on co-purchasing
or browsing data), without an interface that makes use of visual information to
serve the above needs. In this paper, we attempt to fill this gap by designing
and implementing an image-based query system, called Fashionista, which
provides a graphical interface to help users efficiently explore those items
that are not only visually similar to a given query, but which are also
fashionable, as determined by visually-aware recommendation approaches.
Methodologically, Fashionista learns a low-dimensional visual space as well as
the evolution of fashion trends from large corpora of binary feedback data such
as purchase histories of Women's Clothing & Accessories from Amazon, which we
use for this demonstration.


abstract:
  In this article, we introduce Cohn path algebras of higher-rank graphs. We
prove that for a higher-rank graph $\Lambda $, there exists a higher-rank graph
$T\Lambda $ such that the Cohn path algebra of $\Lambda $ is isomorphic to the
Kumjian-Pask algebra of $T\Lambda $. We then use this isomorphism and
properties of Kumjian-Pask algebras to study Cohn path algebras. This includes
proving a uniqueness theorem for Cohn path algebras.


title:
Immunization and targeted destruction of networks using explosive
  percolation

abstract:
  A new method (`explosive immunization' (EI)) is proposed for immunization and
targeted destruction of networks. It combines the explosive percolation (EP)
paradigm with the idea of maintaining a fragmented distribution of clusters.
The ability of each node to block the spread of an infection (or to prevent the
existence of a large cluster of connected nodes) is estimated by a score. The
algorithm proceeds by first identifying low score nodes that should not be
vaccinated/destroyed, analogously to the links selected in EP if they do not
lead to large clusters. As in EP, this is done by selecting the worst node
(weakest blocker) from a finite set of randomly chosen `candidates'. Tests on
several real-world and model networks suggest that the method is more efficient
and faster than any existing immunization strategy. Due to the latter property
it can deal with very large networks.


title: Waveform Design for Wireless Power Transfer

abstract:
  Far-field Wireless Power Transfer (WPT) has attracted significant attention
in recent years. Despite the rapid progress, the emphasis of the research
community in the last decade has remained largely concentrated on improving the
design of energy harvester (so-called rectenna) and has left aside the effect
of transmitter design. In this paper, we study the design of transmit waveform
so as to enhance the DC power at the output of the rectenna. We derive a
tractable model of the non-linearity of the rectenna and compare with a linear
model conventionally used in the literature. We then use those models to design
novel multisine waveforms that are adaptive to the channel state information
(CSI). Interestingly, while the linear model favours narrowband transmission
with all the power allocated to a single frequency, the non-linear model
favours a power allocation over multiple frequencies. Through realistic
simulations, waveforms designed based on the non-linear model are shown to
provide significant gains (in terms of harvested DC power) over those designed
based on the linear model and over non-adaptive waveforms. We also compute
analytically the theoretical scaling laws of the harvested energy for various
waveforms as a function of the number of sinewaves and transmit antennas. Those
scaling laws highlight the benefits of CSI knowledge at the transmitter in WPT
and of a WPT design based on a non-linear rectenna model over a linear model.
Results also motivate the study of a promising architecture relying on
large-scale multisine multi-antenna waveforms for WPT. As a final note, results
stress the importance of modeling and accounting for the non-linearity of the
rectenna in any system design involving wireless power.


title:
An Operator-Based Local Discontinuous Galerkin Method Compatible With
  the BSSN Formulation of the Einstein Equations

abstract:
  Discontinuous Galerkin Finite Element (DGFE) methods offer a mathematically
beautiful, computationally efficient, and efficiently parallelizable way to
solve hyperbolic partial differential equations. These properties make them
highly desirable for numerical calculations in relativistic astrophysics and
many other fields. The BSSN formulation of the Einstein equations has
repeatedly demonstrated its robustness. The formulation is not only stable but
allows for puncture-type evolutions of black hole systems. To-date no one has
been able to solve the full (3+1)-dimensional BSSN equations using DGFE
methods. This is partly because DGFE discretization often occurs at the level
of the equations, not the derivative operator, and partly because DGFE methods
are traditionally formulated for manifestly flux-conservative systems. By
discretizing the derivative operator, we generalize a particular flavor of DGFE
methods, Local DG methods, to solve arbitrary second-order hyperbolic
equations. Because we discretize at the level of the derivative operator, our
method can be interpreted as either a DGFE method or as a finite differences
stencil with non-constant coefficients.


title:
Quasisymmetric Functions from Combinatorial Hopf Monoids and Ehrhart
  Theory

abstract:
  We investigate quasisymmetric functions coming from combinatorial Hopf
monoids. We show that these invariants arise naturally in Ehrhart theory, and
that some of their specializations are Hilbert functions for relative
simplicial complexes. This class of complexes, called forbidden composition
complexes, also forms a Hopf monoid, thus demonstrating a link between Hopf
algebras, Ehrhart theory, and commutative algebra. We also study various
specializations of quasisymmetric functions.


title:
Neural Attention Models for Sequence Classification: Analysis and
  Application to Key Term Extraction and Dialogue Act Detection

abstract:
  Recurrent neural network architectures combining with attention mechanism, or
neural attention model, have shown promising performance recently for the tasks
including speech recognition, image caption generation, visual question
answering and machine translation. In this paper, neural attention model is
applied on two sequence classification tasks, dialogue act detection and key
term extraction. In the sequence labeling tasks, the model input is a sequence,
and the output is the label of the input sequence. The major difficulty of
sequence labeling is that when the input sequence is long, it can include many
noisy or irrelevant part. If the information in the whole sequence is treated
equally, the noisy or irrelevant part may degrade the classification
performance. The attention mechanism is helpful for sequence classification
task because it is capable of highlighting important part among the entire
sequence for the classification task. The experimental results show that with
the attention mechanism, discernible improvements were achieved in the sequence
labeling task considered here. The roles of the attention mechanism in the
tasks are further analyzed and visualized in this paper.


title: Minimal area surfaces dual to Wilson loops and the Mathieu equation

abstract:
  The AdS/CFT correspondence relates Wilson loops in N=4 SYM to minimal area
surfaces in $AdS_5\times S^5$ space. Recently, a new approach to study minimal
area surfaces in $AdS_3 \subset AdS_5$ was discussed based on a Schroedinger
equation with a periodic potential determined by the Schwarzian derivative of
the shape of the Wilson loop. Here we use the Mathieu equation, a standard
example of a periodic potential, to obtain a class of Wilson loops such that
the area of the dual minimal area surface can be computed analytically in terms
of eigenvalues of such equation. As opposed to previous examples, these minimal
surfaces have an umbilical point (where the principal curvatures are equal) and
are invariant under $\lambda$-deformations. In various limits they reduce to
the single and multiple wound circular Wilson loop and to the regular
light-like polygons studied by Alday and Maldacena. In this last limit, the
periodic potential becomes a series of deep wells each related to a light-like
segment. Small corrections are described by a tight--binding approximation. In
the circular limit they are well approximated by an expansion developed by
A.Dekel. In the particular case of no umbilical points they reduce to a
previous solution proposed by J. Toledo. The construction works both in
Euclidean and Minkowski signature of $AdS_3$.


title:
Effect of periodic potential on exciton states in semiconductor carbon
  nanotubes

abstract:
  We develop a theoretical background to treat exciton states of semiconductor
single-walled carbon nanotubes (SWCNTs) in presence of a periodic potential
induced by the surface acoustic wave (SAW) propagating along semiconducting
SWCNT. The formalism naturally accounts for the electronic bands splitting into
the Floquet sub-bands brought about by the Bragg scattering on the SAW
potential. Optically induced transitions within the Floquet states and
formation of correlated electron-hole pairs, i.e., exciton states, are examined
numerically. We discuss dynamical formation of new van Hove singularities
within electron-hole continuum and associated reduction of the exciton
oscillator strengths and its effect on the photoluminescence quenching in
presence of the SAW. We argue that SAW induced dynamical gaps in the single
particle dispersion leads to redistribution of the oscillator strength from
excitons to the Floquet edge states. The simulations also confirm exciton
energy Stark red shift as well as reduction in the binding energy. Comparison
of our results with previous theoretical and experimental studies is provided.


title: Graphical Perception in Animated Bar Charts

abstract:
  Interactive visual applications create animations that encode changes in the
data. For example, cross-filtering dynamically updates linked visualizations
based on the user's continuous brushing actions. The animated effects resulting
from these interactions depends both on how interaction (e.g., brushing speed)
controls properties of the animation such as frame rate, as well as how the
data that is being explored dictates the data encoded in the animation. Past
work has found that frame rate matters to general perception, however a
critical question is which of these animation and data properties affects the
perceptual accuracy of judgement tasks, and to what extent. Although graphical
perception has been well studied for static data visualizations, it is ripe for
exploration in the animated setting. We designed two animated judgment tasks of
a target bar in an animated bar chart and empirically evaluate the effects of 2
animations properties - highlighting of the target bar and frame rate - as well
as 3 data properties that affect the target bar's value throughout the
animation. In short, we find that the rate and timing of animation changes is
easier detected in larger values; that encodings such as color are easier to
detect than shapes; and that timing is important - earlier changes were harder
to perceive as compared to later changes in the animation. Our results are an
initial step to understanding perceptual accuracy for animated data
visualizations, both for presentations and ultimately as part of interactive
applications.


title: Relativistic observer and Maxwell equations

abstract:
  The Ehresmann connection on a fiber bundle that is not compatible with a
(possible) Lie group structure is illustrated by the geometry of a general
anholonomic observer in the Minkowski space. The 3D split of Maxwell's
equations induces geometric terms that are the (generalized) curvature and
torque of the connection. The notion of torque is introduced here as a Lie
coalgebra-valued endomorphism field and measures the deviation of a connection
from being principal.


title:
A track-before-detect labelled multi-Bernoulli particle filter with
  label switching

abstract:
  This paper presents a multitarget tracking particle filter (PF) for general
track-before-detect measurement models. The PF is presented in the random
finite set framework and uses a labelled multi-Bernoulli approximation. We also
present a label switching improvement algorithm based on Markov chain Monte
Carlo that is expected to increase filter performance if targets get in close
proximity for a sufficiently long time. The PF is tested in two challenging
numerical examples.


title: The fine structure of operator mice

abstract:
  We develop the theory of abstract fine structural operators and
operator-premice. We identify properties, which we require of operator-premice
and operators, which ensure that certain basic facts about standard premice
generalize. We define fine condensation for operators $\mathcal{F}$ and show
that fine condensation and iterability together ensure that $\mathcal{F}$-mice
have the fundamental fine structural properties including universality and
solidity of the standard parameter.


title:
Dynamical Electroweak Symmetry Breaking in the model of
  electroweak-scale right-handed neutrinos

abstract:
  We present the Higgs mechanism in the context of the EW-scale $\nu_R$ model
in which electroweak symmetry is dynamically broken by condensates of mirror
quark and right-handed neutrino through the exchange of one fundamental Higgs
doublet and one fundamental Higgs triplet, respectively. The formation of these
condensates is dynamically investigated by using the Schwinger-Dyson approach.
The occurrence of these condensates will give rise to the rich Higgs spectrum.
In addition, the VEVs of Higgs fields is also discussed in this dynamical
phenomenon.


title:
Ensemble Monte Carlo for III-V and Si n-channel FinFETs considering
  non-equilibrium degenerate statistics and quantum-confined scattering

abstract:
  Particle-based ensemble semi-classical Monte Carlo (MC) methods employ
quantum corrections (QCs) to address quantum confinement and degenerate carrier
populations to model tomorrow's ultra-scaled MOSFETs. Here we present new
approaches to quantum confinement and carrier degeneracy effects in a
three-dimensional (3D) MC device simulator, and illustrate their significance
through simulation of n-channel Si and III-V FinFETs. Original contributions
include our treatment of far-from-equilibrium degenerate statistics and
QC-based modeling of surface-roughness scattering, as well as considering
quantum-confined phonon and impurity scattering in 3D. Typical MC simulations
approximate degenerate carrier populations as Fermi distributions to model the
Pauli-blocking (PB) of scattering to occupied final states. To allow for
increasingly far-from-equilibrium non-Fermi carrier distributions in
ultra-scaled devices, we instead generate the final-state occupation
probabilities used for PB by sampling the local carrier populations as a
function of energy and energy valley. This process is aided by the use of
fractional carriers or sub-carriers, which minimizes classical carrier-carrier
scattering. Quantum confinement effects are addressed through
quantum-correction potentials (QCPs) generated from Schr\"{o}dinger-Poisson
solvers, as commonly done. However, we use our valley- and
orientation-dependent QCPs not just to redistribute carriers in real space, or
even among energy valleys, but also to calculate confinement-dependent phonon,
impurity, and surface-roughness scattering rates. FinFET simulations are used
to illustrate how, collectively, these quantum effects can substantially reduce
and even eliminate otherwise expected benefits of
In$_{\text{0.53}}$Ga$_{\text{0.47}}$As FinFETs over otherwise identical Si
FinFETs, despite higher thermal velocities in
In$_{\text{0.53}}$Ga$_{\text{0.47}}$As.


title:
Graphene bubbles on a substrate : Universal shape and van der Waals
  pressure

abstract:
  Trapped substances between a 2D crystal, such as graphene, and an atomically
flat substrate, for example, hexagonal boron nitride, give rise to the
formation of bubbles. We show that the size, shape and internal pressure inside
these bubbles are determined by the competition between van der Waals
attraction of a 2D crystal to the substrate and the elastic energy needed to
deform the atomically thin layer. This presents opportunities to use bubbles to
study the elasticity of 2D materials as well as the conditions of confinement,
yet none of these have been explored so far, either theoretically or
experimentally. We have created a variety of bubbles formed by monolayers of
graphene, hBN and MoS2 mechanically exfoliated onto hBN, graphite and MoS2
substrates. Their shapes, analyzed using atomic force microscopy, are found to
exhibit universal scaling with well-defined aspect ratios, in agreement with
theoretical analysis based on general properties of membranes. We also measured
the pressure induced by the confinement, which increased with decreasing
bubble's size and reached tens on MPa inside submicron bubbles. This agrees
with our theory estimates and suggests that for bubbles with radii < 10 nm
hydrostatic pressures can reach close to 1 GPa, which may modify the properties
of a trapped material.


title: Automated point-neuron simplification of data-driven microcircuit models

abstract:
  A method is presented for the reduction of morphologically detailed
microcircuit models to a point-neuron representation without human
intervention. The simplification occurs in a modular workflow, in the
neighborhood of a user specified network activity state for the reference
model, the "operating point". First, synapses are moved to the soma, correcting
for dendritic filtering by low-pass filtering the delivered synaptic current.
Filter parameters are computed numerically and independently for inhibitory and
excitatory input using a Green's function approach. Next, point-neuron models
for each neuron in the microcircuit are fit to their respective morphologically
detailed counterparts. Here, generalized integrate-and-fire point neuron models
are used, leveraging a recently published fitting toolbox. The fits are
constrained by currents and voltages computed in the morphologically detailed
partner neurons with soma corrected synapses at three depolarizations about the
user specified operating point. The result is a simplified circuit which is
well constrained by the reference circuit, and can be continuously updated as
the latter iteratively integrates new data. The modularity of the approach
makes it applicable also for other point-neuron and synapse models. The
approach is demonstrated on a recently reported reconstruction of a neocortical
microcircuit around an in vivo-like working point. The resulting simplified
network model is benchmarked to the reference morphologically detailed
microcircuit model for a range of simulated network protocols. The simplified
network is found to be slightly more sub-critical than the reference, with
otherwise good agreement for both quantitative and qualitative validations.


title:
Plasticity-induced restructuring of a nanocrystalline grain boundary
  network

abstract:
  The grain boundary-mediated mechanisms that control plastic deformation of
nanocrystalline metals should cause evolution of the grain boundary network,
since they directly alter misorientation relationships between crystals.
Unfortunately, current experimental techniques are unable to track such
evolution, due to limits on both spatial and temporal resolution. In this work,
molecular dynamics simulations are used to study grain boundary restructuring
in nanocrystalline Al during both monotonic tension and cyclic loading. This
task is enabled by the creation of new analysis tools for atomistic datasets
that allow for a complete characterization and tracking of microstructural
descriptors of the grain boundary network. Quantitative measurements of grain
boundary character distribution, triple junction type, grain boundary plane
normal, and other interfacial network characteristics are extracted and
analyzed. The results presented here show that nanocrystalline plasticity leads
to an increase in special boundary fraction and disruption of two-dimensional
boundary connectivity, with the most dramatic evolution occurring in the
smallest grain sizes.


title: H{\alpha} Imaging of Nearby Seyfert Host Galaxies

abstract:
  We used narrowband interference filters with the CCD imaging camera on the
Nickel 1.0 meter telescope at Lick Observatory to observe 31 nearby (z < 0.03)
Seyfert galaxies in the 12 {\mu}m Active Galaxy Sample. We obtained pure
emission line images of each galaxy in order to separate H{\alpha} emission
from the nucleus from that of the host galaxy. The extended H{\alpha} emission
is expected to be powered by newly formed hot stars, and correlates well with
other indicators of current star formation in these galaxies: 7.7 {\mu}m PAH,
far-infrared, and radio luminosity. Relative to what would be expected from
recent star formation, there is a 0.8 dex excess of radio emission in our
Seyfert galaxies. The nuclear H{\alpha} luminosity is dominated by the AGN, and
is correlated with the hard X-ray luminosity. There is an upward offset of 1
dex in this correlation for the Seyfert 1s due to a strong contribution from
the Broad Line Region. We found a correlation between star formation rate and
AGN luminosity. In spite of selection effects, we concluded that the absence of
bright Seyfert nuclei in galaxies with low SFRs is real, albeit only weakly
significant. We used our measured spatial distributions of H{\alpha} emission
to determine what these Seyfert galaxies would look like when observed through
fixed apertures at high redshifts. Although all would be detectable emission
line galaxies at any redshift, most would appear dominated by HII region
emission. Only the most luminous AGN would still be identified at z~0.3.


title: ISM gas studies towards the TeV PWN HESS J1825-137 and northern region

abstract:
  HESS J1825-137 is a pulsar wind nebula (PWN) whose TeV emission extends
across ~1 deg. Its large asymmetric shape indicates that its progenitor
supernova interacted with a molecular cloud located in the north of the PWN as
detected by previous CO Galactic survey (e.g Lemiere, Terrier &
Djannati-Ata\"i 2006). Here we provide a detailed picture of the ISM towards
the region north of HESS J1825-137, with the analysis of the dense molecular
gas from our 7mm and 12mm Mopra survey and the more diffuse molecular gas from
the Nanten CO(1-0) and GRS $^{13}$CO(1-0) surveys. Our focus is the possible
association between HESS J1825-137 and the unidentified TeV source to the
north, HESS J1826-130. We report several dense molecular regions whose
kinematic distance matched the dispersion measured distance of the pulsar.
Among them, the dense molecular gas located at (RA,
Dec)=(18.421h,-13.282$^{\circ}$) shows enhanced turbulence and we suggest that
the velocity structure in this region may be explained by a cloud-cloud
collision scenario. Furthermore, the presence of a H$\alpha$ rim may be the
first evidence of the progenitor SNR of the pulsar PSR J1826-1334 as the
distance between the H$\alpha$ rim and the TeV source matched with the
predicted SNR radius R$_{\text{SNR}}$~120 pc. From our ISM study, we identify a
few plausible origins of the HESS J1826-130 emission, including the progenitor
SNR of PSR J1826-1334 and the PWN G018.5-0.4 powered by PSR J1826-1256. A
deeper TeV study however, is required to fully identify the origin of this
mysterious TeV source.


title: Learning warps object representations in the ventral temporal cortex

abstract:
  The human ventral temporal cortex (VTC) plays a critical role in object
recognition. Although it is well established that visual experience shapes VTC
object representations, the impact of semantic and contextual learning is
unclear. In this study, we tracked changes in representations of novel visual
objects that emerged after learning meaningful information about each object.
Over multiple training sessions, participants learned to associate semantic
features (e.g. made of wood, floats) and spatial contextual associations (e.g.
found in gardens) with novel objects. Functional magnetic resonance imaging was
used to examine VTC activity for objects before and after learning.
Multivariate pattern similarity analyses revealed that, after learning, VTC
activity patterns carried information about the learned contextual associations
of the objects, such that objects with contextual associations exhibited higher
pattern similarity after learning. Further, these learning-induced increases in
pattern information about contextual associations were correlated with
reductions in pattern information about the objects visual features. In a
second experiment, we validated that these contextual effects translated to
real-life objects. Our findings demonstrate that visual object representations
in VTC are shaped by the knowledge we have about objects, and show that object
representations can flexibly adapt as a consequence of learning with the
changes related to the specific kind of newly acquired information.


title: Variational reaction-diffusion systems for semantic segmentation

abstract:
  A novel global energy model for multi-class semantic image segmentation is
proposed that admits very efficient exact inference and derivative calculations
for learning. Inference in this model is equivalent to MAP inference in a
particular kind of vector-valued Gaussian Markov random field, and ultimately
reduces to solving a linear system of linear PDEs known as a reaction-diffusion
system. Solving this system can be achieved in time scaling near-linearly in
the number of image pixels by reducing it to sequential FFTs, after a linear
change of basis. The efficiency and differentiability of the model make it
especially well-suited for integration with convolutional neural networks, even
allowing it to be used in interior, feature-generating layers and stacked
multiple times. Experimental results are shown demonstrating that the model can
be employed profitably in conjunction with different convolutional net
architectures, and that doing so compares favorably to joint training of a
fully-connected CRF with a convolutional net.


title: Devising local protocols for multipartite quantum measurements

abstract:
  We provide a method of designing protocols for implementing multipartite
quantum measurements when the parties are restricted to local operations and
classical communication (LOCC). For each finite integer number of rounds, $r$,
the method succeeds in every case for which an $r$-round protocol exists for
the measurement under consideration, and failure of the method has the
immediate implication that the measurement under consideration cannot be
implemented by LOCC no matter how many rounds of communication are allowed,
including when the number of rounds is allowed to be infinite. It turns out
that this method shows---often with relative ease---the impossibility by LOCC
for a number of examples, including cases where this was not previously known,
as well as the example that first demonstrated what has famously become known
as nonlocality without entanglement.


title: Effects of Nonlocality on Transfer Reactions

abstract:
  We solved the nonlocal scattering and bound state equations using the
Perey-Buck type interaction, and compared to local equivalent calculations.
Using the distorted wave Born approximation we construct the T-matrix for (p,d)
transfer on 17O, 41Ca, 49Ca, 127Sn, 133Sn, and 209Pb at 20 and 50 MeV.
Additionally we studied (p,d) reactions on 40Ca using the the nonlocal
dispersive optical model. We have also included nonlocality consistently into
the adiabatic distorted wave approximation and have investigated the effects of
nonlocality on on (d,p) transfer reactions for deuterons impinged on 16O, 40Ca,
48Ca, 126Sn, 132Sn, 208Pb at 10, 20, and 50 MeV. We found that for bound states
the Perry corrected wave functions resulting from the local equation agreed
well with that from the nonlocal equation in the interior region, but
discrepancies were found in the surface and peripheral regions. Overall, the
Perey correction factor was adequate for scattering states, with the exception
for a few partial waves. Nonlocality in the proton scattering state reduced the
amplitude of the wave function in the nuclear interior. The same was seen for
nonlocality in the deuteron scattering state, but the wave function was also
shifted outward. In distorted wave Born approximation studies of (p,d)
reactions using the Perey-Buck potential, we found that transfer distributions
at the first peak differed by 15-35% as compared to the distribution resulting
from local potentials. When using the dispersive optical model, this
discrepancies grew to 30-50%. When nonlocality was included consistently within
the adiabatic distorted wave approximation, the disagreement was found to be
~40%. This highlights the necessity to pursue reaction formalisms that include
nonlocality exactly.


title:
Holographic Schwinger effect in a confining D3-brane background with
  chemical potential

abstract:
  Using the AdS/CFT correspondence, we investigate the Schwinger effect in a
confining D3-brane background with chemical potential. The potential between a
test particle pair on the D3-brane in an external electric field is obtained.
The critical field $E_c$ in this case is calculated. Also, we apply numerical
method to evaluate the production rate for various cases. The results imply
that the presence of chemical potential tends to suppress the pair production
effect.


title:
Observation of 2D fermionic Mott insulators of $^{40}$K with single-site
  resolution

abstract:
  We report on the site-resolved observation of characteristic states of the
two-dimensional repulsive Fermi-Hubbard model, using ultracold $^{40}$K atoms
in an optical lattice. By varying the tunneling, interaction strength, and
external confinement, we realize metallic, Mott-insulating, and band-insulating
states. We directly measure the local moment, which quantifies the degree of
on-site magnetization, as a function of temperature and chemical potential.
Entropies per particle as low as $0.99(6)\,k_B$ indicate that nearest-neighbor
antiferromagnetic correlations should be detectable using spin-sensitive
imaging.


title: Occupation times of general L\'evy processes

abstract:
  For an arbitrary L\'evy process $X$ which is not a compound Poisson process,
we are interested in its occupation times. We use a quite novel and useful
approach to derive formulas for the Laplace transform of the joint distribution
of $X$ and its occupation times. Our formulas are compact, and more
importantly, the forms of the formulas clearly demonstrate the essential
quantities for the calculation of occupation times of $X$. It is believed that
our results are important not only for the study of stochastic processes, but
also for financial applications.


title:
Thermoluminescent characteristics of LiF:Mg,Cu,P and CaSO$_4$:Dy for low
  dose measurement

abstract:
  Thermoluminescence (TL) characteristics for LiF:Mg,Cu,P, and CaSO$_4$:Dy
under the homogeneous field of X-ray beams of diagnostic irradiation and its
verification using thermoluminescence dosimetry is presented. The irradiation
were performed utilizing a conventional X-ray equipment installed at the
Hospital Ju\'arez Norte of M\'exico. Different thermoluminescence
characteristics of two material were studied, such as batch homogeneity, glow
curve, linearity, detection threshold, reproducibility, relative sensitivity
and fading. Materials were calibrated in terms of absorbed dose to the standard
calibration distance and they were positioned in a generic phantom. The dose
analysis, verification and comparison with the measurements obtained by the
TLD-100 were performed. Results indicate that the dosimetric peak appears at
202$^o$C and 277.5$^o$C for LiF:Mg,Cu,P and CaSO$_4$:Dy, respectively. TL
response as a function of X-ray dose showed a linearity behavior in the very
low dose range for all materials. However, the TLD-100 is not accurate for
measurements below $4mGy$. CaSO$_4$:Dy is 80\% more sensitive than TLD-100 and
it show the lowest detection threshold, whereas LiF:Mg,Cu,P is 60\% more
sensitive than TLD-100. All material showed very good repeatability. Fading for
a period of one month at room temperature showed low fading LiF:Mg,Cu,P, medium
and high for TLD-100 and CaSO$_4$:Dy. The results suggest that CaSO$_4$:Dy and
LiF:Mg,Cu,P are suitable for measurements at low doses used in radiodiagnostic.


title:
Inverse problems for Jacobi operators IV: Interior mass-spring
  perturbations of semi-infinite systems

abstract:
  This work gives results on the interplay of the spectra of two Jacobi
operators corresponding to an infinite mass-spring system and a modification of
it obtained by changing one mass and one spring of the system. It is shown that
the system can be recovered from these two spectra. Necessary and sufficient
conditions for two sequences to be the spectra of the mass-spring system and
the perturbed one are provided.


title: A Compositional Approach to Language Modeling

abstract:
  Traditional language models treat language as a finite state automaton on a
probability space over words. This is a very strong assumption when modeling
something inherently complex such as language. In this paper, we challenge this
by showing how the linear chain assumption inherent in previous work can be
translated into a sequential composition tree. We then propose a new model that
marginalizes over all possible composition trees thereby removing any
underlying structural assumptions. As the partition function of this new model
is intractable, we use a recently proposed sentence level evaluation metric
Contrastive Entropy to evaluate our model. Given this new evaluation metric, we
report more than 100% improvement across distortion levels over current state
of the art recurrent neural network based language models.


title:
On Schauder estimates for a class of nonlocal fully nonlinear parabolic
  equations

abstract:
  We obtain Schauder estimates for a class of concave fully nonlinear nonlocal
parabolic equations of order $\sigma\in (0,2)$ with rough and non-symmetric
kernels. As a application, we prove that the solution to a translation
invariant equation with merely bounded data is $C^\sigma$ in $x$ variable and
$\Lambda^1$ in $t$ variable, where $\Lambda^1$ is the Zygmund space.


title: Lyman continuum leaking AGN in the SSA22 field

abstract:
  Subaru/SuprimeCam narrowband photometry of the SSA22 field reveals the
presence of four Lyman continuum (LyC) candidates among a sample of 14 AGN. Two
show offsets and likely have stellar LyC in nature or are foreground
contaminants. The remaining two LyC candidates are Type I AGN. We argue that
the average LyC escape fraction of high redshift low luminosity AGN is not
likely to be unity, as often assumed in the literature. From direct measurement
we obtain the average LyC-to-UV flux density ratio and ionizing emissivity for
a number of AGN classes and find it at least a factor of two lower than values
obtained assuming f_esc = 1. Comparing to recent Ly{\alpha} forest
measurements, AGNs at redshift z~3 make up at most ~12% and as little as ~5% of
the total ionizing budget. Our results suggest that AGNs are unlikely to
dominate the ionization budget of the Universe at high redshifts.


title: Effect of Bitcoin fee on transaction-confirmation process

abstract:
  In Bitcoin system, transactions are prioritized according to transaction
fees. Transactions without fees are given low priority and likely to wait for
confirmation. Because the demand of micro payment in Bitcoin is expected to
increase due to low remittance cost, it is important to quantitatively
investigate how transactions with small fees of Bitcoin affect the
transaction-confirmation time. In this paper, we analyze the
transaction-confirmation time by queueing theory. We model the
transaction-confirmation process of Bitcoin as a priority queueing system with
batch service, deriving the mean transaction-confirmation time. Numerical
examples show how the demand of transactions with low fees affects the
transaction-confirmation time. We also consider the effect of the maximum block
size on the transaction-confirmation time.


title: A bijective proof of the Cauchy identity for Grothendieck polynomials

abstract:
  We consider pairs of a set-valued column-strict tableau and a reverse plane
partition of the same shape. We introduce algortithms for them, which implies a
bijective proof for the finite sum Cauchy identity for Grothendieck polynomials
and dual Grothendieck polynomials.


title: Option pricing under fast-varying long-memory stochastic volatility

abstract:
  Recent empirical studies suggest that the volatility of an underlying price
process may have correlations that decay slowly under certain market
conditions. In this paper, the volatility is modeled as a stationary process
with long-range correlation properties in order to capture such a situation,
and we consider European option pricing. This means that the volatility process
is neither a Markov process nor a martingale. However, by exploiting the fact
that the price process is still a semimartingale and accordingly using the
martingale method, we can obtain an analytical expression for the option price
in the regime where the volatility process is fast mean-reverting. The
volatility process is modeled as a smooth and bounded function of a fractional
Ornstein-Uhlenbeck process. We give the expression for the implied volatility,
which has a fractional term structure.


title: Dynamic Symmetries and Quantum Nonadiabatic Transitions

abstract:
  Kramers degeneracy theorem is one of the basic results in quantum mechanics.
According to it, the time-reversal symmetry makes each energy level of a
half-integer spin system at least doubly degenerate, meaning the absence of
transitions or scatterings between degenerate states if the Hamiltonian does
not depend on time explicitly. We generalize this result to the case of
explicitly time-dependent spin Hamiltonians. We prove that for a spin system
with the total spin being a half integer, if its Hamiltonian and the evolution
time interval are symmetric under a specifically defined time reversal
operation, the scattering amplitude between an arbitrary initial state and its
time reversed counterpart is exactly zero. We also discuss applications of this
result to the multistate Landau-Zener (LZ) theory.

categories: quant-ph cond-mat.mes-hall math-ph math.MP


title:
Secret-Key Agreement with Public Discussion subject to an Amplitude
  Constraint

abstract:
  This paper considers the problem of secret-key agreement with public
discussion subject to a peak power constraint $A$ on the channel input. The
optimal input distribution is proved to be discrete with finite support. The
result is obtained by first transforming the secret-key channel model into an
equivalent Gaussian wiretap channel with better noise statistics at the
legitimate receiver and then using the fact that the optimal distribution of
the Gaussian wiretap channel is discrete. To overcome the computationally heavy
search for the optimal discrete distribution, several suboptimal schemes are
proposed and shown numerically to perform close to the capacity. Moreover,
lower and upper bounds for the secret-key capacity are provided and used to
prove that the secret-key capacity converges for asymptotic high values of $A$,
to the secret-key capacity with an average power constraint $A^2$. Finally,
when the amplitude constraint A is small ($A \to 0$), the secret-key capacity
is proved to be asymptotically equal to the capacity of the legitimate user
with an amplitude constraint A and no secrecy constraint.


title:
Evidence of both surface and bulk Dirac bands in ZrSiS and the
  unconventional magnetoresistance

abstract:
  The unconventional magnetoresistance of ZrSiS single crystals is found
unsaturated till the magnetic field of 53 T with the butterfly shaped angular
dependence. Intense Shubnikov-de Haas oscillations resolve a bulk Dirac cone
with a nontrivial Berry phase, where the Fermi surface area is 1.80*10^-3
{\AA}-2 and reaches the quantum limit before 20 T. Angle resolved photoemission
spectroscopy measurement reveals an electronic state with the two-dimensional
nature around the X point of Brillouin zone boundary. By integrating the
density functional theory calculations, ZrSiS is suggested to be a Dirac
material with both surface and bulk Dirac bands.


title:
Krawtchouk matrices from the Feynman path integral and from the split
  quaternions

abstract:
  An interpretation of Krawtchouk matrices in terms of discrete version of the
Feynman path integral is given. Also, an algebraic characterization in terms of
the algebra of split quaternions is provided. The resulting properties include
an easy inference of the spectral decomposition. It is also an occasion for an
expository clarification of the role of Krawtchouk matrices in different areas,
including quantum information.


title:
Crossover phenomena of percolation transition in evolution networks with
  hybrid attachment

abstract:
  A first-order percolation transition, called explosive percolation, was
recently discovered in evolution networks with random edge selection under a
certain restriction. However, the network percolation with more realistic
evolution mechanisms such as preferential attachment has not yet been
concerned. We propose a tunable network percolation model by introducing a
hybrid mechanism of edge selection into the Bohman-Frieze-Wormald model, in
which a parameter adjusts the relative weights between random and preferential
selections. A large number of simulations indicate that there exist crossover
phenomena of percolation transition by adjusting the parameter in the evolution
processes. When the strategy of selecting a candidate edge is dominated by
random selection, a single discontinuous percolation transition occurs. When a
candidate edge is selected more preferentially based on node's degree, the size
of the largest component undergoes multiple discontinuous jumps, which exhibits
a peculiar difference from the network percolation of random selection with a
certain restriction. Besides, the percolation transition becomes continuous
when the candidate edge is selected completely preferentially.


title: Computing Join Queries with Functional Dependencies

abstract:
  Recently, Gottlob, Lee, Valiant, and Valiant (GLVV) presented an output size
bound for join queries with functional dependencies (FD), based on a linear
program on polymatroids. GLVV bound strictly generalizes the bound of Atserias,
Grohe and Marx (AGM) for queries with no FD, in which case there are known
algorithms running within AGM bound and thus are worst-case optimal.
  A main result of this paper is an algorithm for computing join queries with
FDs, running within GLVV bound up to a poly-log factor. In particular, our
algorithm is worst-case optimal for any query where the GLVV bound is tight. As
an unexpected by-product, our algorithm manages to solve a harder problem,
where (some) input relations may have prescribed maximum degree bounds, of
which both functional dependencies and cardinality bounds are special cases.
  We extend Gottlob et al. framework by replacing all variable subsets with the
lattice of closed sets (under the given FDs). This gives us new insights into
the structure of the worst-case bound and worst-case instances. While it is
still open whether GLVV bound is tight in general, we show that it is tight on
distributive lattices and some other simple lattices. Distributive lattices
capture a strict superset of queries with no FD and with simple FDs. We also
present two simpler algorithms which are also worst-case optimal on
distributive lattices within a single-$\log$ factor, but they do not match GLVV
bound on a general lattice. Our algorithms are designed based on a novel
principle: we turn a proof of a polymatroid-based output size bound into an
algorithm.


title: A Spectroscopic Survey of Massive Stars in M31 and M33

abstract:
  We describe our spectroscopic follow-up to the Local Group Galaxy Survey
(LGGS) photometry of M31 and M33. We have obtained new spectroscopy of 1895
stars, allowing us to classify 1496 of them for the first time. Our study has
identified many foreground stars, and established membership for hundreds of
early- and mid-type supergiants. We have also found 9 new candidate Luminous
Blue Variables and a previously unrecognized Wolf-Rayet star. We republish the
LGGS M31 and M33 catalogs with improved coordinates and including spectroscopy
from the literature and our new results. The spectroscopy in this paper is
responsible for the vast majority of the stellar classifications in these two
nearby spiral neighbors. The most luminous (and hence massive) of the stars in
our sample are early-type B supergiants, as expected; the more massive O stars
will be fainter visually, and thus mostly remain unobserved so far. The
majority of the unevolved stars in our sample are in the 20-40Mo range.


title: Tropical Coordinates on the Space of Persistence Barcodes

abstract:
  The aim of applied topology is to use and develop topological methods for
applied mathematics, science and engineering. One of the main tools is
persistent homology, an adaptation of classical homology, which assigns a
barcode, i.e. a collection of intervals, to a finite metric space. Because of
the nature of the invariant, barcodes are not well-adapted for use by
practitioners in machine learning tasks. We can circumvent this problem by
assigning numerical quantities to barcodes and these outputs can then be used
as input to standard algorithms. It is the purpose of this paper to identify
tropical coordinates on the space of barcodes and prove that they are stable
with respect to the bottleneck distance and Wasserstein distances.


title: Wrapped microlocal sheaves on pairs of pants

abstract:
  Inspired by the geometry of wrapped Fukaya categories, we introduce the
notion of wrapped microlocal sheaves. We show that traditional microlocal
sheaves are equivalent to functionals on wrapped microlocal sheaves, in analogy
with the expected relation of infinitesimal to wrapped Fukaya categories. As an
application, we calculate wrapped microlocal sheaves on higher-dimensional
pairs of pants, confirming expectations from mirror symmetry.


title:
Linear determinantal representations of smooth plane cubics over finite
  fields

abstract:
  In this note, we study linear determinantal representations of smooth plane
cubics over finite fields. We give an explicit formula of linear determinantal
representations corresponding to rational points. Using Schoof's formula, we
count the number of projective equivalence classes of smooth plane cubics over
a finite field admitting prescribed number of equivalence classes of linear
determinantal representations. As an application, we determine isomorphism
classes of smooth plane cubics over a finite field with 0, 1 or 2 equivalence
classes of linear determinantal representations.


title: Publicly Verifiable Blind Quantum Computation

abstract:
  Blind quantum computation protocols allow a user with limited quantum
technology to delegate an intractable computation to a quantum server while
keeping the computation perfectly secret. Whereas in some protocols a user can
verify that calculated outcomes are correct, a third party cannot do this,
which allows a dishonest user or owner to benefit illegally. I propose a new
blind quantum computation protocol with a new property called public
verifiability, which enables any third party to assure that a party does not
benefit from attempted deception.


title:
Domain Adaptation of Recurrent Neural Networks for Natural Language
  Understanding

abstract:
  The goal of this paper is to use multi-task learning to efficiently scale
slot filling models for natural language understanding to handle multiple
target tasks or domains. The key to scalability is reducing the amount of
training data needed to learn a model for a new task. The proposed multi-task
model delivers better performance with less data by leveraging patterns that it
learns from the other tasks. The approach supports an open vocabulary, which
allows the models to generalize to unseen words, which is particularly
important when very little training data is used. A newly collected
crowd-sourced data set, covering four different domains, is used to demonstrate
the effectiveness of the domain adaptation and open vocabulary techniques.


title:
Data Injection Attacks on Smart Grids with Multiple Adversaries: A
  Game-Theoretic Perspective

abstract:
  Data injection attacks have recently emerged as a significant threat on the
smart power grid. By launching data injection attacks, an adversary can
manipulate the real-time locational marginal prices to obtain economic
benefits. Despite the surge of existing literature on data injection, most such
works assume the presence of a single attacker and assume no cost for attack or
defense. In contrast, in this paper, a model for data injection attacks with
multiple adversaries and a single smart grid defender is introduced. To study
the defender-attackers interaction, two game models are considered. In the
first, a Stackelberg game model is used in which the defender acts as a leader
that can anticipate the actions of the adversaries, that act as followers,
before deciding on which measurements to protect. The existence and properties
of the Stackelberg equilibrium of this game are studied. To find the
equilibrium, a distributed learning algorithm that operates under limited
system information is proposed and shown to converge to the game solution. In
the second proposed game model, it is considered that the defender cannot
anticipate the actions of the adversaries. To this end, we proposed a hybrid
satisfaction equilibrium - Nash equilibrium game and defined its equilibrium
concept. A search algorithm is also provided to find the equilibrium of the
hybrid game. Numerical results using the IEEE 30-bus system are used to
illustrate and analyze the strategic interactions between the attackers and
defender. Our results show that by defending a very small set of measurements,
the grid operator can achieve an equilibrium through which the optimal attacks
have no effect on the system. Moreover, our results show how, at equilibrium,
multiple attackers can play a destructive role towards each other, by choosing
to carry out attacks that cancel each other out, leaving the system unaffected.


title:
Semi-supervised and Unsupervised Methods for Categorizing Posts in Web
  Discussion Forums

abstract:
  Web discussion forums are used by millions of people worldwide to share
information belonging to a variety of domains such as automotive vehicles,
pets, sports, etc. They typically contain posts that fall into different
categories such as problem, solution, feedback, spam, etc. Automatic
identification of these categories can aid information retrieval that is
tailored for specific user requirements. Previously, a number of supervised
methods have attempted to solve this problem; however, these depend on the
availability of abundant training data. A few existing unsupervised and
semi-supervised approaches are either focused on identifying a single category
or do not report category-specific performance. In contrast, this work proposes
unsupervised and semi-supervised methods that require no or minimal training
data to achieve this objective without compromising on performance. A
fine-grained analysis is also carried out to discuss their limitations. The
proposed methods are based on sequence models (specifically, Hidden Markov
Models) that can model language for each category using word and part-of-speech
probability distributions, and manually specified features. Empirical
evaluations across domains demonstrate that the proposed methods are better
suited for this task than existing ones.


title: Coherent Microwave Control of Ultracold $^{23}$Na$^{40}$K Molecules

abstract:
  We demonstrate coherent microwave control of rotational and hyperfine states
of trapped, ultracold, and chemically stable $^{23}$Na$^{40}$K molecules.
Starting with all molecules in the absolute rovibrational and hyperfine ground
state, we study rotational transitions in combined magnetic and electric fields
and explain the rich hyperfine structure. Following the transfer of the entire
molecular ensemble into a single hyperfine level of the first rotationally
excited state, $J{=}1$, we observe collisional lifetimes of more than $3\, \rm
s$, comparable to those in the rovibrational ground state, $J{=}0$. Long-lived
ensembles and full quantum state control are prerequisites for the use of
ultracold molecules in quantum simulation, precision measurements and quantum
information processing.

categories: cond-mat.quant-gas physics.atom-ph physics.chem-ph quant-ph


title:
Common fixed point theorems for Hybrid generalized
  $(F,\varphi)$-contractions under common limit range property with
  applications

abstract:
  We consider a relatively new hybrid generalized F-contraction involving a
pair of mappings and utilize the same to prove a common fixed point theorem for
a hybrid pair of occasionally coincidentally idempotent mappings satisfying
generalized $(F,\varphi)$-contraction condition under common limit range
property in complete metric spaces. A similar result involving a hybrid pair of
mappings satisfying a Rational type Hardy-Rogers $(F,\varphi)$-contractive
condition is also proved. Our results generalize and improve several results of
the existing literature. As applications of our results, we prove two theorems
for the existence of solutions of certain system of functional equations
arising in dynamic programming, and Volterra integral inclusion besides
providing an illustrative example.


title:
Topological edge Mott insulating state in two dimensions at finite
  temperatures -bulk and edge analysis-

abstract:
  We study a bilayer Kane-Mele-Hubbard model with lattice distortion and
inter-layer spin exchange interaction under cylinder geometry. Our analysis
based on real-space dynamical mean field theory with continuous-time quantum
Monte Carlo demonstrates the emergence of a topological edge Mott insulating
(TEMI) state which hosts gapless edge modes only in collective spin
excitations. This is confirmed by the numerical calculations at finite
temperatures for the spin-Hall conductivity and the single-particle excitation
spectrum; the spin Hall conductivity is almost quantized,
$\sigma^{xy}_\mathrm{spin}\sim2(e/2\pi)$, predicting gapless edge modes
carrying the spin current, while the helical edge modes in the single-particle
spectrum are gapped out with respecting symmetry. It is clarified how the TEMI
state evolves from the ordinary spin Hall insulating state with increasing the
Hubbard interaction at a given temperature and then undergoes a phase
transition to a trivial Mott insulating state. With a bosonization approach at
zero temperature, we further address which collective modes host gapless edge
modes in the TEMI state.


title: Higgs exotic decays in general NMSSM with self-interacting dark matter

abstract:
  Under current LHC and dark matter constraints, the general NMSSM can have
self-interacting dark matter to explain the cosmological small structure. In
this scenario, the dark matter is the light singlino-like neutralino ($\chi$)
which self-interacts through exchanging the light singlet-like scalars ($h_1,
a_1$). These light scalars and neutralinos inevitably interact with the 125 GeV
SM-like Higgs boson ($h_{SM}$), which cause the Higgs exotic decays $h_{SM} \to
h_1 h_1, a_1 a_1, \chi\chi$. We first demonstrate the parameter space required
by the explanation of the cosmological small structure and then display the
Higgs exotic decays. We find that in such a parameter space the Higgs exotic
decays can have branching ratios of a few percent, which should be accessible
in the future $e^+e^-$ colliders.


title: Quantum discord of X-states as optimization of one variable function

abstract:
  We solve the quantum discord completely as an optimization of certain one
variable function for arbitrary two qubit X state. Exact solutions of the
quantum discord are obtained for several nontrivial regions of the five
parametric space for the quantum state. Exceptional solutions are determined
via an iterative algorithm.


title:
AttSum: Joint Learning of Focusing and Summarization with Neural
  Attention

abstract:
  Query relevance ranking and sentence saliency ranking are the two main tasks
in extractive query-focused summarization. Previous supervised summarization
systems often perform the two tasks in isolation. However, since reference
summaries are the trade-off between relevance and saliency, using them as
supervision, neither of the two rankers could be trained well. This paper
proposes a novel summarization system called AttSum, which tackles the two
tasks jointly. It automatically learns distributed representations for
sentences as well as the document cluster. Meanwhile, it applies the attention
mechanism to simulate the attentive reading of human behavior when a query is
given. Extensive experiments are conducted on DUC query-focused summarization
benchmark datasets. Without using any hand-crafted features, AttSum achieves
competitive performance. It is also observed that the sentences recognized to
focus on the query indeed meet the query need.


title: Nonparametric Spherical Topic Modeling with Word Embeddings

abstract:
  Traditional topic models do not account for semantic regularities in
language. Recent distributional representations of words exhibit semantic
consistency over directional metrics such as cosine similarity. However,
neither categorical nor Gaussian observational distributions used in existing
topic models are appropriate to leverage such correlations. In this paper, we
propose to use the von Mises-Fisher distribution to model the density of words
over a unit sphere. Such a representation is well-suited for directional data.
We use a Hierarchical Dirichlet Process for our base topic model and propose an
efficient inference algorithm based on Stochastic Variational Inference. This
model enables us to naturally exploit the semantic structures of word
embeddings while flexibly discovering the number of topics. Experiments
demonstrate that our method outperforms competitive approaches in terms of
topic coherence on two different text corpora while offering efficient
inference.


title: On mutation of {\tau}-tilting modules

abstract:
  Mutation of {\tau}-tilting modules is a basic operation to construct a new
support {\tau}-tilting module from a given one by replacing a direct summand.
The aim of this paper is to give a positive answer to the question posed in
[AIR, Question 2.31] about mutation of {\tau}-tilting modules.


title:
Effect of near-earth thunderstorms electric field on the intensity of
  ground cosmic ray positrons/electrons in Tibet

abstract:
  Monte Carlo simulations are performed to study the correlation between the
ground cosmic ray intensity and near-earth thunderstorms electric field at YBJ
(4300 m a.s.l., Tibet, China). The variations of the secondary cosmic ray
intensity are found to be highly dependent on the strength and polarity of the
electric field. In negative fields and in positive fields greater than 600
V/cm, the total number of ground comic ray positrons and electrons increases
with increasing electric field strength. And these values increase more
obviously when involving a shower with lower primary energy or a higher zenith
angle. While in positive fields ranging from 0 to 600 V/cm, the total number of
ground comic ray positrons and electrons declines and the amplitude is up to
3.1% for vertical showers. A decrease of intensity occurs for inclined showers
in positive fields less than 500 V/cm, which is accompanied by smaller
amplitudes. In this paper, the intensity changes are discussed, especially
concerning the decreases in positive electric fields. Our simulation results
are in good agreement with ground-based experimental results obtained from
ARGO-YBJ and the Carpet air shower array. These results could be helpful in
understanding the acceleration mechanisms of secondary charged particles caused
by an atmospheric electric field.


title: A millisecond pulsar in an extremely wide binary system

abstract:
  We report on 22 yrs of radio timing observations of the millisecond pulsar
J1024$-$0719 by the telescopes participating in the European Pulsar Timing
Array (EPTA). These observations reveal a significant second derivative of the
pulsar spin frequency and confirm the discrepancy between the parallax and
Shklovskii distances that has been reported earlier. We also present optical
astrometry, photometry and spectroscopy of 2MASS J10243869$-$0719190. We find
that it is a low-metallicity main-sequence star (K7V spectral type,
$\mathrm{[M/H]}=-1.0$, $T_\mathrm{eff}=4050\pm50$ K) and that its position,
proper motion and distance are consistent with those of PSR J1024$-$0719. We
conclude that PSR J1024$-$0719 and 2MASS J10243869$-$0719190 form a common
proper motion pair and are gravitationally bound. The gravitational interaction
between the main-sequence star and the pulsar accounts for the spin frequency
derivatives, which in turn resolves the distance discrepancy. Our observations
suggest that the pulsar and main-sequence star are in an extremely wide
($P_\mathrm{b}>200$ yr) orbit. Combining the radial velocity of the companion
and proper motion of the pulsar, we find that the binary system has a high
spatial velocity of $384\pm45$ km s$^{-1}$ with respect to the local standard
of rest and has a Galactic orbit consistent with halo objects. Since the
observed main-sequence companion star cannot have recycled the pulsar to
millisecond spin periods, an exotic formation scenario is required. We
demonstrate that this extremely wide-orbit binary could have evolved from a
triple system that underwent an asymmetric supernova explosion, though find
that significant fine-tuning during the explosion is required. Finally, we
discuss the implications of the long period orbit on the timing stability of
PSR J1024$-$0719 in light of its inclusion in pulsar timing arrays.


title: Exploring stronger forms of transitivity on G-spaces

abstract:
  In this paper we introduce and study some stronger forms of transitivity like
total transitivity, weakly mixing for maps on G-spaces. We obtain their
relationship with the earlier defined notion of strongly mixing for maps on
G-spaces. We also study G-minimal maps on G-spaces in detail.


title: PSR J1024-0719: A Millisecond Pulsar in an Unusual Long-Period Orbit

abstract:
  PSR J1024$-$0719 is a millisecond pulsar that was long thought to be
isolated. However, puzzling results concerning its velocity, distance, and low
rotational period derivative have led to reexamination of its properties. We
present updated radio timing observations along with new and archival optical
data that show PSR J1024$-$0719 is most likely in a long period (2$-$20 kyr)
binary system with a low-mass ($\approx 0.4\,M_\odot$) low-metallicity ($Z
\approx -0.9\,$ dex) main sequence star. Such a system can explain most of the
anomalous properties of this pulsar. We suggest that this system formed through
a dynamical exchange in a globular cluster that ejected it into a halo orbit,
consistent with the low observed metallicity for the stellar companion. Further
astrometric and radio timing observations such as measurement of the third
period derivative could strongly constrain the range of orbital parameters.


title: Electronic Band Structure Effects in the Stopping of Protons in Copper

abstract:
  We present an ab initio study of the electronic stopping power of protons in
copper over a wide range of proton velocities $v = 0.02-10~\mathrm{a.u.}$ where
we take into account non-linear effects. Time-dependent density functional
theory coupled with molecular dynamics is used to study electronic excitations
produced by energetic protons. A plane-wave pseudopotential scheme is employed
to solve the time-dependent Kohn-Sham equations for a moving ion in a periodic
crystal. The electronic excitations and the band structure determine the
stopping power of the material and alter the interatomic forces for both
channeling and off-channeling trajectories. Our off-channeling results are in
quantitative agreement with experiments, and at low velocity they unveil a
crossover region of superlinear velocity dependence (with a power of $\sim
1.5$) in the velocity range $v = 0.07-0.3~\mathrm{a.u.}$, which we associate to
the copper crystalline electronic band structure. The results are rationalized
by simple band models connecting two separate regimes. We find that the limit
of electronic stopping $v\to 0$ is not as simple as phenomenological models
suggest and it plagued by band-structure effects.


title: Good Practice in CNN Feature Transfer

abstract:
  The objective of this paper is the effective transfer of the Convolutional
Neural Network (CNN) feature in image search and classification.
Systematically, we study three facts in CNN transfer. 1) We demonstrate the
advantage of using images with a properly large size as input to CNN instead of
the conventionally resized one. 2) We benchmark the performance of different
CNN layers improved by average/max pooling on the feature maps. Our observation
suggests that the Conv5 feature yields very competitive accuracy under such
pooling step. 3) We find that the simple combination of pooled features
extracted across various CNN layers is effective in collecting evidences from
both low and high level descriptors. Following these good practices, we are
capable of improving the state of the art on a number of benchmarks to a large
margin.


title:
Gyrokinetic resonant theory of low frequency electromagnetic
  perturbation

abstract:
  It's pointed out that the traditional gyrokinetic theory dealing with low
frequency electromagnetic perturbation violates the near identity
transformation, which is supposed to be obeyed by Lie perturbed transformation
theory, if resonance happens between \omega and k\cdot v. A modification is
given to overcome this problem by not requiring all components in the first
order Lagrangian 1-form equaling zero. A numerical example is given as an
application of the new theory.


title: On the Performance of RF-FSO Links with and without Hybrid ARQ

abstract:
  This paper studies the performance of hybrid radio-frequency (RF) and
free-space optical (FSO) links assuming perfect channel state information (CSI)
at the receiver. Considering the cases with and without hybrid automatic repeat
request (HARQ), we derive closed-form expressions for the message decoding
probabilities as well as the throughput and the outage probability of the
RF-FSO setups. We also evaluate the effect of adaptive power allocation and
different channel conditions on the throughput and the outage probability. The
results show the efficiency of the RF-FSO links in different conditions.


title:
It's Moving! A Probabilistic Model for Causal Motion Segmentation in
  Moving Camera Videos

abstract:
  The human ability to detect and segment moving objects works in the presence
of multiple objects, complex background geometry, motion of the observer, and
even camouflage. In addition to all of this, the ability to detect motion is
nearly instantaneous. While there has been much recent progress in motion
segmentation, it still appears we are far from human capabilities. In this
work, we derive from first principles a new likelihood function for assessing
the probability of an optical flow vector given the 3D motion direction of an
object. This likelihood uses a novel combination of the angle and magnitude of
the optical flow to maximize the information about the true motions of objects.
Using this new likelihood and several innovations in initialization, we develop
a motion segmentation algorithm that beats current state-of-the-art methods by
a large margin. We compare to five state-of-the-art methods on two established
benchmarks, and a third new data set of camouflaged animals, which we introduce
to push motion segmentation to the next level.


title:
Laser frequency locking with 46 GHz offset using an electro-optic
  modulator for magneto-optical trapping of francium atoms

abstract:
  We demonstrated a frequency offset locking between two laser sources using a
waveguide-type electro-optic modulator (EOM) with 10th-order sidebands for
magneto-optical trapping of Fr atoms. The frequency locking error signal was
successfully obtained by performing delayed self-homodyne detection of the beat
signal between the repumping frequency and the 10th-order sideband component of
the trapping light. Sweeping the trapping-light and repumping-light frequencies
with keeping its frequency difference of 46 GHz was confirmed over 1 GHz by
monitoring the Doppler absorption profile of I2. This technique enables us to
search for a resonance frequency of magneto-optical trapping of Fr.


title:
Multiscale model reduction method for Bayesian inverse problems of
  subsurface flow

abstract:
  This work presents a model reduction approach to the inverse problem in the
application of subsurface flows. For the Bayesian inverse problem, the forward
model needs to be repeatedly computed for a large number of samples to get a
stationary chain. This requires large computational efforts. To significantly
improve the computation efficiency, we use generalized multiscale finite
element method and least-squares stochastic collocation method to construct a
reduced computational model. To avoid the difficulty of choosing regularization
parameter, hyperparameters are introduced to build a hierarchical model. We use
truncated Karhunen-Loeve expansion (KLE) to reduce the dimension of the
parameter spaces and decrease the mixed time of Markov chains. The techniques
of hyperparameter and KLE are incorporated into the model reduction method. The
reduced model is constructed offline. Then it is computed very efficiently in
the online sampling stage. This strategy can significantly accelerate the
evaluation of the Markov chain and the resultant posterior distribution
converges fast. We analyze the convergence for the approximation between the
posterior distribution by the reduced model and the reference posterior
distribution by the full-order model. A few numerical examples in subsurface
flows are carried out to demonstrate the performance of the presented model
reduction method with application of the Bayesian inverse problem.


title: Observation of the Type-II Weyl Semimetal Phase in MoTe2

abstract:
  Topological Weyl semimetal (TWS), a new state of quantum matter, has sparked
enormous research interest recently. Possessing unique Weyl fermions in the
bulk and Fermi arcs on the surface, TWSs offer a rare platform for realizing
many exotic physical phenomena. TWSs can be classified into type-I that respect
Lorentz symmetry and type-II that do not. Here, we directly visualize the
electronic structure of MoTe2, a recently proposed type-II TWS. Using
angle-resolved photoemission spectroscopy (ARPES), we unravel the unique
surface Fermi arcs, in good agreement with our ab-initio calculations. From
spin-resolved ARPES measurements, we demonstrate the non-degenerate
spin-texture of surface Fermi-arcs, thereby proving their non-trivial
topological nature. Our work not only lead to new understandings of the unusual
properties discovered in this family of compounds, but also allow for the
further exploration of exotic properties and practical applications of type-II
TWSs, as well as the interplay between superconductivity (MoTe2 was discovered
to be superconducting recently) and their topological order.


title:
Designing New Electrolytes for Lithium Ion Batteries Using Superhalogen
  Anions

abstract:
  The electrolytes used in Lithium Ion Batteries (LIBs) such as LiBF4, LiPF6
etc. are Li-salts of some complex anions, BF4-, PF6- etc. The investigation
shows that the vertical detachment energy (VDE) of these anions exceeds to that
of halogen, and therefore they behave as superhalogen anions. Consequently, it
might be possible to design new electrolytic salts using other superhalogen
anions. We have explored this possibility using Li-salts of various
superhalogen anions such as BO2-, AlH4-, TiH5- and VH6- as well as hyperhalogen
anions, BH4-y(BH4)y-(y = 1 to 4). Our density functional calculations show that
Li-salts of these complex anions possess similar characteristics as those of
electrolytic salts in LIBs. Note that they all are halogen free and hence,
non-toxic and safer than LiBF4, LiPF6 etc. In particular, LiB4H13 and LiB5H16
are two potential candidates for electrolytic salt due to their smaller
Li-dissociation energy ({\Delta}E) than those of LiBF4, LiPF6 etc. We have also
noticed that {\Delta}E of LiBH4-y(BH4)y varies inversely with the VDE of
BH4-y(BH4)y- anions, which increases with the increase in y. These findings may
guide experimentalists and future researchers to design and synthesize more
efficient and environment friendly electrolytic salts for LIBs.


title: Ultra slow-roll G-inflation

abstract:
  The conventional slow-roll approximation is broken in the so-called "ultra
slow-roll" models of inflation, for which the inflaton potential is exactly (or
extremely) flat. The interesting nature of (canonical) ultra slow-roll
inflation is that the curvature perturbation grows on superhorizon scales, but
has a scale-invariant power spectrum. We study the ultra slow-roll inflationary
dynamics in the presence of non-canonical kinetic terms of the scalar field,
namely ultra slow-roll G-inflation. We compute the evolution of the curvature
perturbation and show that the primordial power spectrum follows a broken power
law with an oscillation feature. It is demonstrated that this could explain the
lack of large-scale power in the cosmic microwave background temperature
anisotropies. We also point out that the violation of the null energy condition
is prohibited in ultra slow-roll G-inflation and hence a blue tensor tilt is
impossible as long as inflation is driven by the potential. This statement is,
however, not true if the energy density is dominated by the kinetic energy of
the scalar field.


title: Asymptotic behavior of positively curved steady Ricci Solitons, II

abstract:
  In this note, we show that any $n$-dimensional $\kappa$-noncollapsed steady
K\"ahler-Ricci soliton with nonnegative bisectional curvature must be flat. The
result is an improvement to our former work in \cite{DZ2}.


title:
On-chip storage of broadband photonic qubits in a cavity-protected
  rare-earth ensemble

abstract:
  Ensembles of solid-state optical emitters enable broadband quantum storage
and transduction of photonic qubits, with applications in high-rate optical
quantum networks for secure communications, global time-keeping, and
interconnecting future quantum computers. To realize coherent quantum
information transfer using ensembles, spin rephasing techniques are currently
used to mitigate fast decoherence resulting from inhomogeneous broadening. Here
we use a dense ensemble of neodymium rare-earth ions strongly coupled to a
nanophotonic resonator to demonstrate that decoherence of a single photon
excitation is near-completely suppressed via cavity protection- a new technique
for accessing the decoherence-free subspace of collective coupling. The
protected Rabi oscillations between the cavity field and the atomic
superradiant state thereby enable ultra-fast transfer of photonic frequency
qubits (~50 GHz bandwidth) into the ions, followed by retrieval with 98.7%
fidelity. By coupling the superradiant excitation to other long-lived
rare-earth spin states, this technology will enable broadband, always-ready
quantum memories and fast optical-to-microwave transducers.


title: Low-metallicity Young Clusters in the Outer Galaxy. II. Sh 2-208

abstract:
  We obtained deep near-infrared images of Sh 2-208, one of the
lowest-metallicity HII regions in the Galaxy, [O/H] = -0.8 dex. We detected a
young cluster in the center of the HII region with a limiting magnitude of K =
18.0 mag (10sigma), which corresponds to a mass detection limit of ~0.2 M_sun.
This enables the comparison of star-forming properties under low metallicity
with those of the solar neighborhood. We identified 89 cluster members. From
the fitting of the K-band luminosity function (KLF), the age and distance of
the cluster are estimated to be ~0.5 Myr and ~4 kpc, respectively. The
estimated young age is consistent with the detection of strong CO emission in
the cluster region and the estimated large extinction of cluster members (Av ~
4--25 mag). The observed KLF suggests that the underlying initial mass function
(IMF) of the low-metallicity cluster is not significantly different from
canonical IMFs in the solar neighborhood in terms of both high-mass slope and
IMF peak (characteristic mass). Despite the very young age, the disk fraction
of the cluster is estimated at only 27pm6 %, which is significantly lower than
those in the solar metallicity. Those results are similar to Sh 2-207, which is
another low-metallicity star-forming region close to Sh 2-208 with a separation
of 12 pc,suggesting that their star-forming activities in low-metallicity
environments are essentially identical to those in the solar neighborhood,
except for the disk dispersal timescale. From large-scale mid-infrared images,
we suggest that sequential star formation is taking place in Sh 2-207, Sh 2-208
and the surrounding region, triggered by an expanding bubble with a ~30 pc
radius.


title: Coherence non-generating channels

abstract:
  We define the coherence non-generating channel as the completely positive
trace-preserving map which does not generate quantum coherence from an
incoherent state. The incoherent operations are the strict subset of the
coherence non-generating channels. We prove that the relative entropy of
coherence is monotonically decreasing under the coherence non-generating
channels, while the coherence of formation may increase under such channels.
Interestingly, by combining mathematically the coherence of formation to the
entanglement of formation, we show that the coherence of formation of a
single-qubit is never increased by a coherence non-generating channel. This
leads to the superadditivity property for the coherence increasing power of
quantum channels, namely, while two channels can not increase coherence
individually, they may increase the quantum coherence of a composed system.
Further, we derive the general form of the rank-2 coherence non-generating
qubit channels. Our results contribute to the resource theory of quantum
coherence.


title: Pre-symplectic algebroids and their applications

abstract:
  In this paper, we introduce the notion of a pre-symplectic algebroid, and
show that there is a one-to-one correspondence between pre-symplectic
algebroids and symplectic Lie algebroids. This result is the geometric
generalization of the relation between left-symmetric algebras and symplectic
(Frobenius) Lie algebras. Although pre-symplectic algebroids are not
left-symmetric algebroids, they still can be viewed as the underlying
structures of symplectic Lie algebroids. %We study three classes of
pre-symplectic algebroids in detail. Then we study exact pre-symplectic
algebroids and show that they are classified by the third cohomology group of a
left-symmetric algebroid. Finally, we study para-complex pre-symplectic
algebroids. Associated to a para-complex pre-symplectic algebroid, there is a
pseudo-Riemannian Lie algebroid. The multiplication in a para-complex
pre-symplectic algebroid characterizes the restriction to the Lagrangian
subalgebroids of the Levi-Civita connection in the corresponding
pseudo-Riemannian Lie algebroid.


title: Learning a Pose Lexicon for Semantic Action Recognition

abstract:
  This paper presents a novel method for learning a pose lexicon comprising
semantic poses defined by textual instructions and their associated visual
poses defined by visual features. The proposed method simultaneously takes two
input streams, semantic poses and visual pose candidates, and statistically
learns a mapping between them to construct the lexicon. With the learned
lexicon, action recognition can be cast as the problem of finding the maximum
translation probability of a sequence of semantic poses given a stream of
visual pose candidates. Experiments evaluating pre-trained and zero-shot action
recognition conducted on MSRC-12 gesture and WorkoutSu-10 exercise datasets
were used to verify the efficacy of the proposed method.


title: Market Integration in the Prewar Japanese Rice Markets

abstract:
  This paper examines the integration process of the Japanese major rice
markets (Tokyo and Osaka) from 1881 to 1932. Using a non-Bayesian time-varying
vector error correction model, we argue that the process strongly depended on
the government's policy on the network system of the telegram and telephone;
rice traders with an intention to use modern communication tools were usually
affected by the changes in policy. We find that (i) the Japanese rice markets
had been integrated in the 1910s; (ii) increasing use of telegraphs had
accelerated rice market integration from the Meiji period in Japan; and (iii)
local telephone system, which reduced the time spent by urban users sending and
receiving telegrams, promoted market integration.