title: Very Deep Convolutional Networks for Text Classification

abstract:
  The dominant approach for many NLP tasks are recurrent neural networks, in
particular LSTMs, and convolutional neural networks. However, these
architectures are rather shallow in comparison to the deep convolutional
networks which have pushed the state-of-the-art in computer vision. We present
a new architecture (VDCNN) for text processing which operates directly at the
character level and uses only small convolutions and pooling operations. We are
able to show that the performance of this model increases with depth: using up
to 29 convolutional layers, we report improvements over the state-of-the-art on
several public text classification tasks. To the best of our knowledge, this is
the first time that very deep convolutional nets have been applied to text
processing.


title: To replace or not to replace in finite population sampling

abstract:
  We revisit the classical result in finite population sampling which states
that in equally-likely "simple" random sampling the sample mean is more
reliable when we do not replace after each draw. In this paper we investigate
if and when the same is true for samples where it may no longer be true that
each member of the population has an equal chance of being selected. For a
certain class of sampling schemes, we are able to obtain convenient expressions
for the variance of the sample mean and surprisingly, we find that for some
selection distributions a more reliable estimate of the population mean will
happen by replacing after each draw. We show for selection distributions lying
in a certain polytope the classical result prevails.


title: Lonely Runner Polyhedra

abstract:
  We study the \emph{Lonely Runner Conjecture}, conceived by J\"org M.~Wills in
the 1960's: Given positive integers $n_1, n_2, \dots, n_k$, there exists a
positive real number $t$ such that for all $1 \le j \le k$ the distance of $t
\, n_j$ to the nearest integer is at least $\frac{ 1 }{ k+1 }$. Continuing a
view-obstruction approach by Cusick and recent work by Henze and Malikiosis,
our goal is to promote a polyhedral \emph{ansatz} to the Lonely Runner
Conjecture. Our results include geometric proofs of some folklore results that
are only implicit in the existing literature, a new family of affirmative
instances defined by the parities of the speeds, and geometrically motivated
conjectures whose resolution would shed further light on the Lonely Runner
Conjecture.


title:
The heat equation for the Dirichlet fractional Laplacian with Hardy's
  potentials: properties of minimal solutions and blow-up

abstract:
  Local and global properties of minimal solutions for the heat equation
generated by the Dirichlet fractional Laplacian negatively perturbed by Hardy's
potentials on open subsets of $\R^d$ are analyzed. As a byproduct we obtain
instantaneous blow-up of nonnegative solutions in the supercritical case.


title:
Predictions for Dusty Mass Loss from Asteroids during Close Encounters
  with Solar Probe Plus

abstract:
  The Solar Probe Plus (SPP) mission will explore the Sun's corona and
innermost solar wind starting in 2018. The spacecraft will also come close to a
number of Mercury-crossing asteroids with perihelia less than 0.3 AU. At small
heliocentric distances, these objects may begin to lose mass, thus becoming
"active asteroids" with comet-like comae or tails. This paper assembles a
database of 97 known Mercury-crossing asteroids that may be encountered by SPP,
and it presents estimates of their time-dependent visible-light fluxes and mass
loss rates. Assuming a similar efficiency of sky background subtraction as was
achieved by STEREO, we find that approximately 80% of these asteroids are
bright enough to be observed by the Wide-field Imager for SPP (WISPR). A model
of gas/dust mass loss from these asteroids is developed and calibrated against
existing observations. This model is used to estimate the visible-light fluxes
and spatial extents of spherical comae. Observable dust clouds occur only when
the asteroids approach the Sun closer than 0.2 AU. The model predicts that
during the primary SPP mission between 2018 and 2025, there should be 113
discrete events (for 24 unique asteroids) during which the modeled comae have
angular sizes resolvable by WISPR. The largest of these correspond to asteroids
3200 Phaethon, 137924, 155140, and 289227, all with angular sizes of roughly 15
to 30 arcminutes. We note that the SPP trajectory may still change, but no
matter the details there should still be multiple opportunities for fruitful
asteroid observations.


title:
On-board monitoring of 2-D spatially-resolved temperatures in
  cylindrical lithium-ion batteries: Part II. State estimation via
  impedance-based temperature sensing

abstract:
  Impedance-based temperature detection (ITD) is a promising approach for rapid
estimation of internal cell temperature based on the correlation between
temperature and electrochemical impedance. Previously, ITD was used as part of
an Extended Kalman Filter (EKF) state-estimator in conjunction with a thermal
model to enable estimation of the 1-D temperature distribution of a cylindrical
lithium-ion battery. Here, we extend this method to enable estimation of the
2-D temperature field of a battery with temperature gradients in both the
radial and axial directions.
  An EKF using a parameterised 2-D spectral-Galerkin model with ITD measurement
input (the imaginary part of the impedance at 215 Hz) is shown to accurately
predict the core temperature and multiple surface temperatures of a 32113
LiFePO$_4$ cell, using current excitation profiles based on an Artemis HEV
drive cycle. The method is validated experimentally on a cell fitted with a
heat sink and asymmetrically cooled via forced air convection.
  A novel approach to impedance-temperature calibration is also presented,
which uses data from a single drive cycle, rather than measurements at multiple
uniform cell temperatures as in previous studies. This greatly reduces the time
required for calibration, since it overcomes the need for repeated cell thermal
equalization.


title: F-string Solution in AdS4 X CP3 PP-wave Background

abstract:
  We present supergravity solution for F-string in pp wave background obtained
from AdS4 X CP3 with zero flat directions.The classical solution is shown to
break all space-time supersymmetries. We explicitly write down the standard as
well as supernumerary Killing spinors both for the background and F-string
solution.


title: Lattice Percolation Approach to 3D Modeling of Tissue Aging

abstract:
  We describe a 3D percolation-type approach to modeling of the processes of
aging and certain other properties of tissues analyzed as systems consisting of
interacting cells. Lattice sites are designated as regular (healthy) cells,
senescent cells, or vacancies left by dead (apoptotic) cells. The system is
then studied dynamically with the ongoing processes including regular cell
dividing to fill vacant sites, healthy cells becoming senescent or dying, and
senescent cells dying. Statistical-mechanics description can provide patterns
of time dependence and snapshots of morphological system properties. The
developed theoretical modeling approach is found not only to corroborate recent
experimental findings that inhibition of senescence can lead to extended
lifespan, but also to confirm that, unlike 2D, in 3D senescent cells can
contribute to tissue's connectivity/mechanical stability. The latter effect
occurs by senescent cells forming the second infinite cluster in the regime
when the regular (healthy) cell's infinite cluster still exits.


title:
Origin and magnitude of 'designer' spin-orbit interaction in graphene on
  semiconducting transition metal dichalcogenides

abstract:
  We use a combination of experimental techniques to demonstrate a general
occurrence of spin-orbit interaction (SOI) in graphene on transition metal
dichalcogenide (TMD) substrates. Our measurements indicate that SOI is
ultra-strong and extremely robust, despite it being merely
interfacially-induced, with neither graphene nor the TMD substrates changing
their structure. This is found to be the case irrespective of the TMD material
used, of the transport regime, of the carrier type in the graphene band, and of
the thickness of the graphene multilayer. Specifically, we perform weak
antilocalization measurements as the simplest and most general diagnostic of
SOI, and show that the spin relaxation time is very short in all cases
regardless of the elastic scattering time. Such a short spin-relaxation time
strongly suggests that the SOI originates from a modification of graphene band
structure. We confirmed this expectation by measuring a gate-dependent beating,
and a corresponding frequency splitting, in the low-field Shubnikov-de Haas
magneto-resistance oscillations in high quality bilayer graphene on WSe$_2$.
These measurements provide an unambiguous diagnostic of a SOI-induced splitting
in the electronic band structure, and their analysis allows us to determine the
SOI coupling constants for the Rashba term and the so-called spin-valley
coupling term, i.e., the terms that were recently predicted theoretically for
interface-induced SOI in graphene. The magnitude of the SOI splitting is found
to be on the order of 10 meV, more than 100 times greater than the SOI
intrinsic to graphene. Both the band character of the interfacially induced
SOI, as well as its robustness and large magnitude make graphene-on-TMD a
promising system to realize and explore a variety of spin-dependent transport
phenomena, such as, in particular, spin-Hall and valley-Hall topological
insulating states.


title: Hawking radiation is corpuscular

abstract:
  The total number of Hawking quanta emitted during the evaporation of a
Schwarzschild black hole is proportional to the square of the initial mass or,
equivalently, to the Bekenstein entropy. This simple, but little appreciated,
fact is interpreted in terms of the recent discovery of black hole soft hair.


title:
Towards Measuring the Ground State Hyperfine Splitting of Antihydrogen
  -- A Progress Report

abstract:
  We report the successful commissioning and testing of a dedicated
field-ioniser chamber for measuring principal quantum number distributions in
antihydrogen as part of the ASACUSA hyperfine spectroscopy apparatus. The new
chamber is combined with a beam normalisation detector that consists of plastic
scintillators and a retractable passivated implanted planar silicon (PIPS)
detector.


title: Neural Machine Translation with External Phrase Memory

abstract:
  In this paper, we propose phraseNet, a neural machine translator with a
phrase memory which stores phrase pairs in symbolic form, mined from corpus or
specified by human experts. For any given source sentence, phraseNet scans the
phrase memory to determine the candidate phrase pairs and integrates tagging
information in the representation of source sentence accordingly. The decoder
utilizes a mixture of word-generating component and phrase-generating
component, with a specifically designed strategy to generate a sequence of
multiple words all at once. The phraseNet not only approaches one step towards
incorporating external knowledge into neural machine translation, but also
makes an effort to extend the word-by-word generation mechanism of recurrent
neural network. Our empirical study on Chinese-to-English translation shows
that, with carefully-chosen phrase table in memory, phraseNet yields 3.45 BLEU
improvement over the generic neural machine translator.


title: Low-rank Optimization with Convex Constraints

abstract:
  The problem of low-rank approximation with convex constraints, which appears
in data analysis, system identification, model order reduction, low-order
controller design and low-complexity modelling is considered. Given a matrix,
the objective is to find a low-rank approximation that meets rank and convex
constraints, while minimizing the distance to the matrix in the squared
Frobenius norm. In many situations, this non-convex problem is convexified by
nuclear norm regularization. However, we will see that the approximations
obtained by this method may be far from optimal. In this paper, we propose an
alternative convex relaxation that uses the convex envelope of the squared
Frobenius norm and the rank constraint. With this approach, easily verifiable
conditions are obtained under which the solutions to the convex relaxation and
the original non-convex problem coincide. An SDP representation of the convex
envelope is derived, which allows us to apply this approach to several known
problems. Our example on optimal low-rank Hankel approximation/model reduction
illustrates that the proposed convex relaxation performs consistently better
than nuclear norm regularization and may outperform balanced truncation.


title:
Asymptotics of Invariant Metrics in the normal direction and a new
  characterisation of the unit disk

abstract:
  We give improvements of estimates of invariant metrics in the normal
direction on strictly pseudoconvex domains. Specifically we will give the
second term in the expansion of the metrics. This depends on an improved
localisation result and estimates in the one variable case. Finally we will
give a new characterisation of the unit disk in $\mathbb C$ in terms of the
asymptotic behaviour of quotients of invariant metrics.


title: The cohomology of semi-infinite Deligne--Lusztig varieties

abstract:
  We prove a 1979 conjecture of Lusztig on the cohomology of semi-infinite
Deligne--Lusztig varieties attached to division algebras over local fields. We
also prove the two conjectures of Boyarchenko on these varieties. It is known
that in this setting, the semi-infinite Deligne--Lusztig varieties are
ind-schemes comprised of limits of certain finite-type schemes $X_h$.
Boyarchenko's two conjectures are on the maximality of $X_h$ and on the
behavior of the torus-eigenspaces of their cohomology. Both of these
conjectures were known in full generality only for division algebras with Hasse
invariant $1/n$ in the case $h = 2$ (the "lowest level") by the work of
Boyarchenko--Weinstein on the cohomology of a special affinoid in the
Lubin--Tate tower. We prove that the number of rational points of $X_h$ attains
its Weil--Deligne bound, so that the cohomology of $X_h$ is pure in a very
strong sense. We prove that the torus-eigenspaces of $H_c^i(X_h)$ are
irreducible representations and are supported in exactly one cohomological
degree. Finally, we give a complete description of the homology groups of the
semi-infinite Deligne--Lusztig varieties attached to any division algebra, thus
giving a geometric realization of the unramified supercuspidal representations
of these groups. We expect that the techniques developed in this paper will be
useful in studying these constructions for reductive groups over local fields
in general.


title: Canonical q-deformations in arithmetic geometry

abstract:
  In recent work with Bhatt and Morrow, we defined a new integral p-adic
cohomology theory interpolating between etale and de Rham cohomology. An
unexpected feature of this cohomology is that in coordinates, it can be
computed by a q-deformation of the de Rham complex, which is thus canonical, at
least in the derived category. In this short survey, we try to explain what we
know about this phenomenon, and what can be conjectured to hold.


title: Directional Multivariate Extremes in Environmental Phenomena

abstract:
  Several environmental phenomena can be described by different correlated
variables that must be considered jointly in order to be more representative of
the nature of these phenomena. For such events, identification of extremes is
inappropriate if it is based on marginal analysis. Extremes have usually been
linked to the notion of quantile, which is an important tool to analyze risk in
the univariate setting. We propose to identify multivariate extremes and
analyze environmental phenomena in terms of the directional multivariate
quantile, which allows us to analyze the data considering all the variables
implied in the phenomena, as well as look at the data in interesting directions
that can better describe an environmental catastrophe. Since there are many
references in the literature that propose extremes detection based on copula
models, we also generalize the copula method by introducing the directional
approach. Advantages and disadvantages of the non-parametric proposal that we
introduce and the copula methods are provided in the paper. We show with
simulated and real data sets how by considering the first principal component
direction we can improve the visualization of extremes. Finally, two cases of
study are analyzed: a synthetic case of flood risk at a dam (a 3-variable
case), and a real case study of sea storms (a 5-variable case).


title: Kramers escape of a self-propelled particle

abstract:
  We investigate the escape rate of an overdamped, self-propelled spherical
Brownian particle on a surface from a metastable potential well. Within a
modeling in terms of a 1D constant speed of the particle's active dynamics we
consider the associated rate using both numerical and analytical approaches.
Regarding the properties of the stationary state in the potential well, two
major timescales exist, each governing the translational and the rotational
dynamics of the particle, respectively. The particle radius is identified to
present the essential quantity in charge of regulating the ratio between those
timescales. For very small and very large particle radii, approximate analytic
expressions for the particle's escape rate can be derived, which, within their
respective range of validity, compare favorably with the precise escape
numerics of the underlying full two-dimensional Fokker-Planck description.


title: Modular non-repeating codes for DNA storage

abstract:
  We describe a strategy for constructing codes for DNA-based information
storage by serial composition of weighted finite-state transducers. The
resulting state machines can integrate correction of substitution errors;
synchronization by interleaving watermark and periodic marker signals;
conversion from binary to ternary, quaternary or mixed-radix sequences via an
efficient block code; encoding into a DNA sequence that avoids homopolymer,
dinucleotide, or trinucleotide runs and other short local repeats; and
detection/correction of errors (including local duplications, burst deletions,
and substitutions) that are characteristic of DNA sequencing technologies. We
present software implementing these codes, available at
github.com/ihh/dnastore, with simulation results demonstrating that the
generated DNA is free of short repeats and can be accurately decoded even in
the presence of substitutions, short duplications and deletions.


title: Finite Sample Analysis of Approximate Message Passing Algorithms

abstract:
  Approximate message passing (AMP) refers to a class of efficient algorithms
for statistical estimation in high-dimensional problems such as compressed
sensing and low-rank matrix estimation. This paper analyzes the performance of
AMP in the regime where the problem dimension is large but finite. For
concreteness, we consider the setting of high-dimensional regression, where the
goal is to estimate a high-dimensional vector $\beta_0$ from a noisy
measurement $y=A \beta_0 + w$. AMP is a low-complexity, scalable algorithm for
this problem. Under suitable assumptions on the measurement matrix $A$, AMP has
the attractive feature that its performance can be accurately characterized in
the large system limit by a simple scalar iteration called state evolution.
Previous proofs of the validity of state evolution have all been asymptotic
convergence results. In this paper, we derive a concentration inequality for
AMP with i.i.d. Gaussian measurement matrices with finite size $n \times N$.
The result shows that the probability of deviation from the state evolution
prediction falls exponentially in $n$. This provides theoretical support for
empirical findings that have demonstrated excellent agreement of AMP
performance with state evolution predictions for moderately large dimensions.
The concentration inequality also indicates that the number of AMP iterations
$t$ can grow no faster than order $\frac{\log n}{\log \log n}$ for the
performance to be close to the state evolution predictions with high
probability. The analysis can be extended to obtain similar non-asymptotic
results for AMP in other settings such as low-rank matrix estimation.


title: Cosmological history in York time: inflation and perturbations

abstract:
  The constant mean extrinsic curvature on a spacelike slice may constitute a
physically preferred time coordinate, `York time'. One line of enquiry to probe
this idea is to understand processes in our cosmological history in terms of
York time. Following a review of the theoretical motivations, we focus on
slow-roll inflation and the freezing and Hubble re-entry of cosmological
perturbations. We show how the mathematical account of these processes is
distinct from the conventional account in terms of standard cosmological or
conformal time. We also consider the cosmological York-timeline more broadly
and contrast it with the conventional cosmological timeline.


title:
Image-Based Modeling of Blood Flow and Oxygen Transfer in Feto-Placental
  Capillaries

abstract:
  During pregnancy, oxygen diffuses from maternal to fetal blood through
villous trees in the placenta. In this paper, we simulate blood flow and oxygen
transfer in feto-placental capillaries by converting three-dimensional
representations of villous and capillary surfaces, reconstructed from confocal
laser scanning microscopy, to finite-element meshes, and calculating values of
vascular flow resistance and total oxygen transfer. The relationship between
the total oxygen transfer rate and the pressure drop through the capillary is
shown to be captured across a wide range of pressure drops by physical scaling
laws and an upper bound on the oxygen transfer rate. A regression equation is
introduced that can be used to estimate the oxygen transfer in a capillary
using the vascular resistance. Two techniques for quantifying the effects of
statistical variability, experimental uncertainty and pathological placental
structure on the calculated properties are then introduced. First, scaling
arguments are used to quantify the sensitivity of the model to uncertainties in
the geometry and the parameters. Second, the effects of localized dilations in
fetal capillaries are investigated using an idealized axisymmetric model, to
quantify the possible effect of pathological placental structure on oxygen
transfer. The model predicts how, for a fixed pressure drop through a
capillary, oxygen transfer is maximized by an optimal width of the dilation.
The results could explain the prevalence of fetal hypoxia in cases of delayed
villous maturation, a pathology characterized by a lack of the
vasculo-syncytial membranes often seen in conjunction with localized capillary
dilations.


title: Homotopical Adjoint Lifting Theorem

abstract:
  This paper provides a homotopical version of the adjoint lifting theorem in
category theory, allowing for Quillen equivalences to be lifted from monoidal
model categories to categories of algebras over colored operads. The generality
of our approach allows us to simultaneously answer questions of rectification
and of changing the base model category to a Quillen equivalent one. We work in
the setting of colored operads, and we do not require them to be
$\Sigma$-cofibrant. Special cases of our main theorem recover many known
results regarding rectification and change of model category, as well as
numerous new results. In particular, we recover a recent result of
Richter-Shipley about a zig-zag of Quillen equivalences between commutative
$H\mathbb{Q}$-algebra spectra and commutative differential graded
$\mathbb{Q}$-algebras, but our version involves only three Quillen equivalences
instead of six. We also work out the theory of how to lift Quillen equivalences
to categories of colored operad algebras after a left Bousfield localization.


title: An ultracold neutron storage bottle for UCN density measurements

abstract:
  We have developed a storage bottle for ultracold neutrons (UCN) in order to
measure the UCN density at the beamports of the Paul Scherrer Institute's (PSI)
UCN source. This paper describes the design, construction and commissioning of
the robust and mobile storage bottle with a volume comparable to typical
storage experiments 32 liter e.g. searching for an electric dipole moment of
the neutron.


title:
A combined Lattice Boltzmann and Immersed Boundary approach for
  predicting the vascular transport of differently shaped particles

abstract:
  Modelling the vascular transport and adhesion of man-made particles is
crucial for optimizing their efficacy in the detection and treatment of
diseases. Here, a Lattice Boltzmann and Immersed Boundary methods are combined
together for predicting the near wall dynamics of particles with different
shapes in a laminar flow. For the lattice Boltzmann modelling, a Gauss-Hermite
projection is used to derive the lattice equation, wall boundary conditions are
imposed through the Zou-He framework, and a moving least squares algorithm
accurately reconstructs the forcing term accounting for the immersed boundary.
First, the computational code is validated against two well-known test cases:
the sedimentation of circular and elliptical cylinders in a quiescent fluid. A
very good agreement is observed between the present results and those available
in the literature. Then, the transport of circular, elliptical, rectangular,
square and triangular particles is analyzed in a Couette flow, at Re=20. All
particles drifted laterally across the stream lines reaching an equilibrium
position, independently of the initial conditions. For this large Reynolds
number, the particle shape has no significant effect on the final equilibrium
position but it does affect the absolute value and periodicity of the angular
velocity. Specifically, elongated particles show longer oscillation periods
and, most interestingly, larger variations in angular velocity. The longest
particles exhibit a zero angular velocity for almost the whole rotational
period. Collectively, this data demonstrates that the proposed approach can be
efficiently used for predicting complex particle dynamics in biologically
relevant flows. This computational strategy could have significant impact in
the field of computational nanomedicine for optimizing the specific delivery of
therapeutic and imaging agents.


title: Two-sided moment estimates for a class of nonnegative chaoses

abstract:
  We derive two-sided bounds for moments of random multilinear forms (random
chaoses) with nonnegative coeficients generated by independent nonnegative
random variables $X_i$ which satisfy the following condition on the growth of
moments: $\lv X_i \rv_{2p} \leq A \lv X_i \rv_p$ for any $i$ and $p\geq 1$.
Estimates are deterministic and exact up to multiplicative constants which
depend only on the order of chaos and the constant $A$ in the moment
assumption.


title:
First-principles calculation of the stabilities of lithium garnet
  compositions against hydration

abstract:
  A series of density functional electronic structure calculations were carried
out to better understand the crystallographic factors governing the stability
of LinA3B2O12 lithium garnet phases against hydration. The reaction studied is
H2O + LinA3B2O12 = LiOH + HnA3B2O12. Most of the compositions are stable
against pure water; the main driving force for instability in the atmosphere is
the reaction of lithium hydroxide with CO2 to make lithium carbonate. The
calculated hydration resistance scales with the Pauling bond valence on the
oxygen atom contributed by the coordinating A and B ions. In the unexchanged
Li-garnets, this bond valence must be balanced by lithium, so there is also a
good overall correlation of hydration stability with lithium stoichiometry (n):
hydration resistance increases in the order Li8-garnet < Li7-garnet <
Li6-garnet < Li5-garnet < Li3-garnet. Only Li3A3B2O12 garnets have proton
exchange energies sufficiently positive to overcome the decomposition energy of
lithium hydroxide into lithium carbonate + water; the n=3 garnets are predicted
to be stable to hydration under atmospheric conditions, in agreement with
observations (Galven et al. Chem. Mater. 2012 24, 3335-3345). At a given
lithium ion stoichiometry, hydration resistance is greater for A, B ions having
smaller ionic radii.


title:
Cloud-Based Big Data Management and Analytics for Scholarly Resources:
  Current Trends, Challenges and Scope for Future Research

abstract:
  With the shifting focus of organizations and governments towards digitization
of academic and technical documents, there has been an increasing need to use
this reserve of scholarly documents for developing applications that can
facilitate and aid in better management of research. In addition to this, the
evolving nature of research problems has made them essentially
interdisciplinary. As a result, there is a growing need for scholarly
applications like collaborator discovery, expert finding and research
recommendation systems. This research paper reviews the current trends and
identifies the challenges existing in the architecture, services and
applications of big scholarly data platform with a specific focus on directions
for future research.


title:
Syzygy bundles and the weak Lefschetz property of almost complete
  intersections

abstract:
  Deciding the presence of the weak Lefschetz property often is a challenging
problem. In this work an in-depth study is carried out in the case of Artinian
monomial ideals with four generators in three variables. We use a connection to
lozenge tilings to describe semistability of the syzygy bundle of such an
ideal, to determine its generic splitting type, and to decide the presence of
the weak Lefschetz property. We provide results in both characteristic zero and
positive characteristic.


title:
Undecidability and Irreducibility Conditions for Open-Ended Evolution
  and Emergence

abstract:
  Is undecidability a requirement for open-ended evolution (OEE)? Using methods
derived from algorithmic complexity theory, we propose robust computational
definitions of open-ended evolution and the adaptability of computable
dynamical systems. Within this framework, we show that decidability imposes
absolute limits to the stable growth of complexity in computable dynamical
systems. Conversely, systems that exhibit (strong) open-ended evolution must be
undecidable, establishing undecidability as a requirement for such systems.
Complexity is assessed in terms of three measures: sophistication, coarse
sophistication and busy beaver logical depth. These three complexity measures
assign low complexity values to random (incompressible) objects. As time grows,
the stated complexity measures allow for the existence of complex states during
the evolution of a computable dynamical system. We show, however, that finding
these states involves undecidable computations. We conjecture that for similar
complexity measures that assign low complexity values, decidability imposes
comparable limits to the stable growth of complexity, and that such behaviour
is necessary for non-trivial evolutionary systems. We show that the
undecidability of adapted states imposes novel and unpredictable behaviour on
the individuals or populations being modelled. Such behaviour is irreducible.
Finally, we offer an example of a system, first proposed by Chaitin, that
exhibits strong OEE.


title: Twisted Light Transmission over 143 kilometers

abstract:
  Spatial modes of light can potentially carry a vast amount of information,
making them promising candidates for both classical and quantum communication.
However, the distribution of such modes over large distances remains difficult.
Intermodal coupling complicates their use with common fibers, while free-space
transmission is thought to be strongly influenced by atmospheric turbulence.
Here we show the transmission of orbital angular momentum modes of light over a
distance of 143 kilometers between two Canary Islands, which is 50 times
greater than the maximum distance achieved previously. As a demonstration of
the transmission quality, we use superpositions of these modes to encode a
short message. At the receiver, an artificial neural network is used for
distinguishing between the different twisted light superpositions. The
algorithm is able to identify different mode superpositions with an accuracy of
more than 80% up to the third mode order, and decode the transmitted message
with an error rate of 8.33%. Using our data, we estimate that the distribution
of orbital angular momentum entanglement over more than 100 kilometers of free
space is feasible. Moreover, the quality of our free-space link can be further
improved by the use of state-of-the-art adaptive optics systems.


title: Some algebras with the weak Lefschetz property

abstract:
  Using a connection to lozenge tilings of triangular regions, we establish an
easily checkable criterion that guarantees the weak Lefschetz property of a
quotient by a monomial ideal. It is also shown that each such ideal also has a
semistable syzygy bundle.


title:
Measurement of the photon identification efficiencies with the ATLAS
  detector using LHC Run-1 data

abstract:
  The algorithms used by the ATLAS Collaboration to reconstruct and identify
prompt photons are described. Measurements of the photon identification
efficiencies are reported, using 4.9 fb$^{-1}$ of pp collision data collected
at the LHC at $\sqrt{s}$=7 TeV and 20.3 fb$^{-1}$ at $\sqrt{s}$=8 TeV. The
efficiencies are measured separately for converted and unconverted photons, in
four different pseudorapidity regions, for transverse momenta between 10 GeV
and 1.5 TeV. The results from the combination of three data-driven techniques
are compared to the predictions from a simulation of the detector response,
after correcting the electromagnetic shower momenta in the simulation for the
average differences observed with respect to data. Data-to-simulation
efficiency ratios used as correction factors in physics measurements are
determined to account for the small residual efficiency differences. These
factors are measured with uncertainties between 0.5% and 10% in 7 TeV data and
between 0.5% and 5.6% in 8 TeV data, depending on the photon transverse
momentum and pseudorapidity.


title: Generalized Permutohedra from Probabilistic Graphical Models

abstract:
  A graphical model encodes conditional independence relations via the Markov
properties. For an undirected graph these conditional independence relations
can be represented by a simple polytope known as the graph associahedron, which
can be constructed as a Minkowski sum of standard simplices. There is an
analogous polytope for conditional independence relations coming from a regular
Gaussian model, and it can be defined using multiinformation or relative
entropy. For directed acyclic graphical models and also for mixed graphical
models containing undirected, directed and bidirected edges, we give a
construction of this polytope, up to equivalence of normal fans, as a Minkowski
sum of matroid polytopes. Finally, we apply this geometric insight to construct
a new ordering-based search algorithm for causal inference via directed acyclic
graphical models.


title:
Measurements of double-helicity asymmetries in inclusive $J/\psi$
  production in longitudinally polarized $p+p$ collisions at $\sqrt{s}=510$ GeV

abstract:
  We report the double helicity asymmetry, $A_{LL}^{J/\psi}$, in inclusive
$J/\psi$ production at forward rapidity as a function of transverse momentum
$p_T$ and rapidity $|y|$. The data analyzed were taken during $\sqrt{s}=510$
GeV longitudinally polarized $p$$+$$p$ collisions at the Relativistic Heavy Ion
Collider (RHIC) in the 2013 run using the PHENIX detector. At this collision
energy, $J/\psi$ particles are predominantly produced through gluon-gluon
scatterings, thus $A_{LL}^{J/\psi}$ is sensitive to the gluon polarization
inside the proton. We measured $A_{LL}^{J/\psi}$ by detecting the decay
daughter muon pairs $\mu^+ \mu^-$ within the PHENIX muon spectrometers in the
rapidity range $1.2<|y|<2.2$. In this kinematic range, we measured the
$A_{LL}^{J/\psi}$ to be $0.012 \pm 0.010$~(stat)~$\pm$~$0.003$(syst). The
$A_{LL}^{J/\psi}$ can be expressed to be proportional to the product of the
gluon polarization distributions at two distinct ranges of Bjorken $x$: one at
moderate range $x \approx 0.05$ where recent RHIC data of jet and $\pi^0$
double helicity spin asymmetries have shown evidence for significant gluon
polarization, and the other one covering the poorly known small-$x$ region $x
\approx 2\times 10^{-3}$. Thus our new results could be used to further
constrain the gluon polarization for $x< 0.05$.


title: Neutrino lighthouse powered by Sagittarius A* disk dynamo

abstract:
  We show that the subset of high energy neutrino events detected by IceCube
which correlate with the Galactic center (within uncertainties of their
reconstructed arrival directions) could originate in the collisions of protons
accelerated by the Sagittarius (Sgr) A* disk dynamo. Under very reasonable
assumptions on source parameters we demonstrate that the supermassive black
hole at the center of the Galaxy could launch protons and nuclei with multi PeV
energies. Acceleration of these particles in a period of seconds up to Lorentz
factors of \sim 10^7 is possible by means of the Blandford-Znajek mechanism,
which wires the spinning magnetosphere of Sgr A* as a Faraday unipolar
inductor. During the acceleration process the \sim PeV progenitors of \sim 50
TeV neutrinos radiate curvature photons in the keV energy range. We show that
IceCube neutrino astronomy with photon tagging on the Chandra X-ray Observatory
could provide a valuable probe for the Blandford-Znajek acceleration mechanism.
We also argue that EeV neutrinos, which may be produced in a similar fashion
during the merging of binary black holes, could become the smoking gun for
particle acceleration in a one-shot boost.


title:
Estimation of maximum possible trapped field in superconducting
  permanent magnets in 2D and 3D

abstract:
  The ability of stacks of superconducting tapes to trap large magnetic fields
makes them ideal candidates for creating powerful permanent magnets of compact
size and mass. Experimentally, several techniques are used to trap the maximum
possible field in a given practical application. However, regardless of the
magnetization method used, there is a physical limit to the maximum magnetic
field that a given superconducting magnet can trap. This limit is given by the
geometric design, the particular superconducting material used and the
temperature of operation. Knowing the maximum possible trapped field is
important for device design as it provides an upper limit for applications such
as magnetic bearings or rotating machinery. In this work we present a
collection of finite element method (FEM) models in 2D and 3D capable of
estimating the maximum trapped field of stacked tape superconducting magnets.
The models are computationally fast and can be used to perform parametric
studies with ease. For the case of square stacks tape magnets, various sizes
are considered and their estimated maximum trapped field is compared with
experimental results.


title: Transverse Single Spin Asymmetry in $p+p^\uparrow \to D +X $

abstract:
  We present expected values of the Single Spin Asymmetry (SSA) in $D$-meson
production in the process $p+p^\uparrow \rightarrow D^0 + X $ at RHIC energy
$(\sqrt{s}=200\text{ GeV})$ using a generalized parton model approach. We use
fits to the gluon Sivers function obtained recently by D'Alesio {\it et al.,}
by fitting to the asymmetry data for the process $p+p^\uparrow \rightarrow
\pi^0+ X$ measured by the PHENIX collaboration at RHIC. These fits give peak
asymmetry predictions which lie in a broad range, $0.5\%\lesssim
A_N\lesssim10\%$ for the kinematic regions considered. This is to be compared
with the upper bound of 18\% expected for the maximal gluon Sivers function. We
extend our analysis to two other centre of mass energies of proposed
experiments - AFTER@LHC $(\sqrt{s}=115\text{ GeV})$ and a future RHIC run
$(\sqrt{s}=500\text{ GeV})$. We further investigate (at $\sqrt{s}=200$ GeV) the
effect of the transverse momentum dependent (TMD) evolution of the unpolarized
parton distribution functions (pdf's) and of the gluon Sivers function on the
asymmetry predictions. We perform this study using an evolution setup given by
Anselmino {\it et al}. We find that the effect of evolution is an overall
reduction of the asymmetry predictions. For example, for the saturated gluon
Sivers function, upon taking into account TMD evolution, peak asymmetry
predictions reduce by a factor 3 or more. This decrease is similar to that
noticed earlier for Single Spin Asymmetries (SSA) in the electroproduction of
$J/\psi$.


title: Near Periodic solution of the Elliptic RTBP for the Jupiter Sun system

abstract:
  Let us consider the elliptic restricted three body problem (Elliptic RTBP)
for the Jupiter Sun system with eccentricity $e=0.048$ and $\mu=0.000953339$.
Let us denote by $T$ the period of their orbits. In this paper we provide
initial conditions for the position and velocity for a spacecraft such that
after one period $T$ the spacecraft comes back to the same place, with the same
velocity, within an error of 4 meters for the position and 0.2 meters per
second for the velocity. Taking this solution as periodic, we present numerical
evidence showing that this solution is stable. In order to compare this
periodic solution with the motion of celestial bodies in our solar system, we
end this paper by providing an ephemeris of the spacecraft motion from February
17, 2017 to December 28, 2028.

categories: math.DS astro-ph.EP physics.class-ph physics.space-ph


title:
Response to rebuttal to Comment on Letter "Excitons in Molecular
  Aggregates with Levy Disorder: Anomalous Localization and Exchange Broadening
  of Optical Spectra", Phys. Rev. Lett. 109, 259701
  (https://arxiv.org/abs/1208.2779)

abstract:
  The Comment to the Letter "Excitons in Molecular Aggregates with Levy
Disorder: Anomalous Localization and Exchange Broadening of Optical Spectra"
appeared in Phys. Rev. Lett. 109, 259701 (submitted on November 28, 2011). I
prepared the below response to the rebuttal received from the Letter's Authors
in the review process. It contains useful comments, which further address the
errors in the Letter and other flaws in Authors' understanding of the topic
revealed in discussion.


title:
The Electron-pair Density Distribution of the ${^{1,3}\Pi_u}$ Excited
  States of H$_2$

abstract:
  The non-monotonic behavior of the electron repulsion energy and the
interelectronic distance, as a function of the internuclear separation, in the
$^{3}\Pi_{u}$ excited state of the hydrogen molecule has been assessed by
explicitly calculation and analysis of the electron-pair density distribution
functions from high level ab initio Full Configuration Interaction wave
functions, for both the $^{3}\Pi_{u}$ and the $^{1}\Pi_{u}$ states.
Additionally, the Hund's rule as applied to these two states has been accounted
for in terms of simple electronic shielding effects induced by wave function
antisymmetrization.


title: ROCS-Derived Features for Virtual Screening

abstract:
  Rapid overlay of chemical structures (ROCS) is a standard tool for the
calculation of 3D shape and chemical ("color") similarity. ROCS uses unweighted
sums to combine many aspects of similarity, yielding parameter-free models for
virtual screening. In this report, we decompose the ROCS color force field into
"color components" and "color atom overlaps", novel color similarity features
that can be weighted in a system-specific manner by machine learning
algorithms. In cross-validation experiments, these additional features
significantly improve virtual screening performance (ROC AUC scores) relative
to standard ROCS.


title: Random Sequential Adsorption on Imprecise Lattice

abstract:
  We report a surprising result, established by numerical simulations and
analytical arguments for a one-dimensional lattice model of random sequential
adsorption, that even an arbitrarily small imprecision in the lattice-site
localization changes the convergence to jamming from fast, exponential, to
slow, power-law, with, for some parameter values, a discontinuous jump in the
jamming coverage value. This finding has implications for irreversible
deposition on patterned substrates with pre-made landing sites for particle
attachment. We also consider a general problem of the particle (depositing
object) size not an exact multiple of the lattice spacing, and the lattice
sites themselves imprecise, broadened into allowed-deposition intervals.
Regions of exponential vs. power-law convergence to jamming are identified, and
certain conclusions regarding the jamming coverage are argued for analytically
and confirmed numerically.


title: A Quantum Abacus based encoding system

abstract:
  A formal description of a quantum abacus based encoding system is presented.
This way of representing data for processing purposes is based on a quantum
algorithm for counting qubits introduced by Lesovik et al.
\cite{LesovikEtal2010} and Suslov et al. \cite{SuslovEtal2011}, but formally
developed in this work. Finally, in order to illustrate the potential of this
proposal, the implementation of the basic quantum array operations through this
encoding system is presented.


title:
Diffusion of Oligonucleotides from within Iron-Crosslinked
  Polyelectrolyte-Modified Alginate Beads: A Model System for Drug Release

abstract:
  We developed and experimentally verified an analytical model to describe
diffusion of oligonucleotides from stable hydrogel beads. The synthesized
alginate beads are Fe3+-cross-linked as well as polyelectrolyte-doped for
uniformity and stability at physiological pH. Data on diffusion of
oligonucleotides from inside the beads provide physical insights into the
volume nature of the immobilization of a fraction of oligonucleotides due to
polyelectrolyte cross-linking, i.e., the absence of the surface-layer barrier
in this case. Furthermore, our results suggest a new simple approach to
measuring the diffusion coefficient of the mobile oligonucleotide molecules
inside hydrogel. The considered alginate beads provide a model for a
well-defined component in drug release systems and for the
oligonucleotide-release transduction steps in drug-delivering and biocomputing
applications. This is illustrated by destabilizing the beads with citrate that
induces full oligonucleotide release with non-diffusional kinetics.


title:
Efficient extraction of zero-phonon-line photons from single
  nitrogen-vacancy centers in an integrated GaP-on-diamond platform

abstract:
  Scaling beyond two-node quantum networks using nitrogen vacancy (NV) centers
in diamond is limited by the low probability of collecting zero phonon line
(ZPL) photons from single centers. Here, we demonstrate GaP-on-diamond disk
resonators which resonantly couple ZPL photons from single NV centers to
single-mode waveguides. In these devices, the probability of a single NV center
emitting a ZPL photon into the guided waveguide mode after optical excitation
can reach 9%, due to a combination of resonant enhancement of the ZPL emission
and efficient coupling between the resonator and waveguide. We verify the
single-photon nature of the emission and experimentally demonstrate both high
in-waveguide photon numbers and substantial Purcell enhancement for a set of
devices. These devices may enable scalable integrated quantum networks based on
NV centers.


title:
Dolbeault-Dirac operators, quantum Clifford algebras and the
  Parthasarathy formula

abstract:
  We consider Dolbeault-Dirac operators on quantized irreducible flag manifolds
as defined by Kr\"ahmer and Tucker-Simmons. We show that, in general, these
operators do not satisfy a formula of Parthasarathy-type. This is a consequence
of two results that we prove here: we always have quadratic commutation
relations for the relevant quantum root vectors, up to terms in the quantized
Levi factor; there are examples of quantum Clifford algebras where the
commutation relations are not of quadratic-constant type.


title: Diffeomorphism Stability and Codimension Three

abstract:
  Given $k\in \mathbb{R},$ $v,$ $D>0,$ and $n\in \mathbb{N},$ let $\left\{
M_{\alpha }\right\} _{\alpha =1}^{\infty }$ be a Gromov-Hausdorff convergent
sequence of Riemannian $n$--manifolds with sectional curvature $\geq k,$ volume
$>v,$ and diameter $\leq D.$ Perelman's Stability Theorem implies that all but
finitely many of the $M_{\alpha }$s are homeomorphic. The Diffeomorphism
Stability Question asks whether all but finitely many of the $ M_{\alpha }$s
are diffeomorphic.
  We answer this question affirmatively in the special case when all of the
singularities of the limit space occur along smoothly and isometrically
embedded Riemannian manifolds of codimension $\leq 3$. We then describe several
applications. For instance, if the limit space is an orbit space whose singular
strata are of codimension at $\leq 3,$ then all but finitely many of the
$M_{\alpha }$s are diffeomorphic.


title: Quantum Spaces are Modular

abstract:
  At present, our notion of space is a classical concept. Taking the point of
view that quantum theory is more fundamental than classical physics, and that
space should be given a purely quantum definition, we revisit the notion of
Euclidean space from the point of view of quantum mechanics. Since space
appears in physics in the form of labels on relativistic fields or Schrodinger
wave functionals, we propose to define Euclidean quantum space as a choice of
polarization for the Heisenberg algebra of quantum theory. We show, following
Mackey, that generically, such polarizations contain a fundamental length scale
and that contrary to what is implied by the Schrodinger polarization, they
possess topologically distinct spectra. These are the modular spaces. We show
that they naturally come equipped with additional geometrical structures
usually encountered in the context of string theory or generalized geometry.
Moreover, we show how modular space reconciles the presence of a fundamental
scale with translation and rotation invariance. We also discuss how the usual
classical notion of space comes out as a form of thermodynamical limit of
modular space while the Schrodinger space is a singular limit.


title:
Exploring the Tomlin-Varadarajan quantum constraints in $U(1)^3$ loop
  quantum gravity: solutions and the Minkowski theorem

abstract:
  We explicitly solved the anomaly-free quantum constraints proposed by Tomlin
and Varadarajan for the weak Euclidean model of canonical loop quantum gravity,
in a large subspace of the model's kinematic Hilbert space which is the space
of the charge network states. In doing so, we first identified the subspace on
which each of the constraints acts convergingly, and then by explicitly
evaluating such actions we found the complete set of the solutions in the
identified subspace. We showed that the space of solutions consists of two
classes of states, with the first class having a property that involves the
condition known from the Minkowski theorem on polyhedra, and the second class
satisfying a weaker form of the spatial diffeomorphism invariance.


title:
Window Parity Games: An Alternative Approach Toward Parity Games with
  Time Bounds

abstract:
  Classical objectives in two-player zero-sum games played on graphs often deal
with limit behaviors of infinite plays: e.g., mean-payoff and total-payoff in
the quantitative setting, or parity in the qualitative one (a canonical way to
encode omega-regular properties). Those objectives offer powerful abstraction
mechanisms and often yield nice properties such as memoryless determinacy.
However, their very nature provides no guarantee on time bounds within which
something good can be witnessed. In this work, we consider two approaches
toward inclusion of time bounds in parity games. The first one, parity-response
games, is based on the notion of finitary parity games [CHH09] and parity games
with costs [FZ14,WZ16]. The second one, window parity games, is inspired by
window mean-payoff games [CDRR15]. We compare the two approaches and show that
while they prove to be equivalent in some contexts, window parity games offer a
more tractable alternative when the time bound is given as a parameter (P-c.
vs. PSPACE-c.). In particular, it provides a conservative approximation of
parity games computable in polynomial time. Furthermore, we extend both
approaches to the multi-dimension setting. We give the full picture for both
types of games with regard to complexity and memory bounds.
  [CHH09] K. Chatterjee, T.A. Henzinger, F. Horn (2009): Finitary winning in
omega-regular games. ACM Trans. Comput. Log. 11(1). [FZ14] N. Fijalkow, M.
Zimmermann (2014): Parity and Streett Games with Costs. LMCS 10(2). [WZ16] A.
Weinert, M. Zimmermann (2016): Easy to Win, Hard to Master: Optimal Strategies
in Parity Games with Costs. Proc. of CSL, LIPIcs, Schloss Dagstuhl - LZI. To
appear. [CDRR15] K. Chatterjee, L. Doyen, M. Randour, J.-F. Raskin (2015):
Looking at mean-payoff and total-payoff through windows. Information and
Computation 242, pp. 25-52.


title: Flatness and Completion Revisited

abstract:
  We continue investigating the interaction between flatness and
$\mathfrak{a}$-adic completion for infinitely generated modules over a
commutative ring $A$. We introduce the concept of $\mathfrak{a}$-adic flatness,
which is weaker than flatness. We prove that $\mathfrak{a}$-adic flatness is
preserved under completion when the ideal $\mathfrak{a}$ is weakly proregular.
We also prove that when $A$ is noetherian, $\mathfrak{a}$-adic flatness
coincides with flatness (for complete modules). An example is worked out of a
non-noetherian ring $A$, with a weakly proregular ideal $\mathfrak{a}$, for
which the completion $\hat{A}$ is not flat. We also study $\mathfrak{a}$-adic
systems, and prove that if the ideal $\mathfrak{a}$ is finitely generated, then
the limit of any $\mathfrak{a}$-adic system is a complete module.


title: Analyzing Distributed Join-Idle-Queue: A Fluid Limit Approach

abstract:
  In the context of load balancing, Lu et al. introduced the distributed
Join-Idle-Queue algorithm, where a group of dispatchers distribute jobs to a
cluster of parallel servers. Each dispatcher maintains a queue of idle servers;
when a job arrives to a dispatcher, it sends it to a server on its queue, or to
a random server if the queue is empty. In turn, when a server has no jobs, it
requests to be placed on the idle queue of a randomly chosen dispatcher.
  Although this algorithm was shown to be quite effective, the original
asymptotic analysis makes simplifying assumptions that become increasingly
inaccurate as the system load increases. Further, the analysis does not
naturally generalize to interesting variations, such as having a server request
to be placed on the idle queue of a dispatcher before it has completed all
jobs, which can be beneficial under high loads.
  We provide a new asymptotic analysis of Join-Idle-Queue systems based on mean
field fluid limit methods, deriving families of differential equations that
describe these systems. Our analysis avoids previous simplifying assumptions,
is empirically more accurate, and generalizes naturally to the variation
described above, as well as other simple variations. Our theoretical and
empirical analyses shed further light on the performance of Join-Idle-Queue,
including potential performance pitfalls under high load.


title:
Length Scale Dependence of Periodic Textures for Photoabsorption
  Enhancement in Ultra-thin Silicon Foils and Thick Wafers

abstract:
  In this paper, we simulate a front surface inverted pyramidal grating texture
on 2 to 400 micron thick silicon and optimize it to derive maximum photocurrent
density from the cell. We identify a one size fits all front grating period of
1000 nm that leads to maximum photo-absorption of normally incident AM1.5g
solar spectrum in silicon (configured with a back surface reflector)
irrespective of the thickness of the crystalline silicon absorbing layer. With
the identification of such universally optimized periodicity for the case of an
inverted pyramidal grating texture, a common fabrication process can be
designed to manufacture high-efficiency devices on crystalline silicon
regardless of wafer thickness. In order to validate the results of the
simulation, we fabricated high resolution inverted pyramidal textures on a 400
micron thick silicon wafer with electron beam lithography to compare the
reflectance from submicron and wavelength scale periodic textures. The
experimental reflectance measurements on textures confirm that a 1000 nm period
grating texture performs better than a 500 nm period texture in reducing
reflectance, in agreement with the simulations.


title: A note about Domination and monotonicity in disordered systems

abstract:
  In this note we establish several inequalities and monotonicity properties
for the free energy of directed polymers under certain stochastic orders: the
usual stochastic order, the Laplace transform order and the convex order. For
the latter our results cover also many classical disordered systems.


title:
Predicting Performance Under Stressful Conditions Using Galvanic Skin
  Response

abstract:
  The rapid growth of the availability of wearable biosensors has created the
opportunity for using biological signals to measure worker performance. An
important question is how to use such signals to not just measure, but actually
predict worker performance on a task under stressful and potentially high risk
conditions. Here we show that the biological signal known as galvanic skin
response (GSR) allows such a prediction. We conduct an experiment where
subjects answer arithmetic questions under low and high stress conditions while
having their GSR monitored using a wearable biosensor. Using only the GSR
measured under low stress conditions, we are able to predict which subjects
will perform well under high stress conditions, achieving an area under the
curve (AUC) of 0.76. If we try to make similar predictions without using any
biometric signals, the AUC barely exceeds 0.50. Our result suggests that
performance in high stress conditions can be predicted using signals obtained
from wearable biosensors in low stress conditions.


title:
Higher codimensional Ueda theory for a compact submanifold with unitary
  flat normal bundle

abstract:
  Let $Y$ be a compact complex manifold embedded in a complex manifold with
unitary flat normal bundle. Our interest is in a sort of the linearizability
problem of a neighborhood of $Y$. As a higher-codimensional generalization of
Ueda's result, we give a sufficient condition for the existence of a
non-singular holomorphic foliation on a neighborhood of $Y$ which includes $Y$
as a leaf with unitary-linear holonomy. We apply this result to the existence
problem of a smooth Hermitian metric with semi-positive curvature on a nef line
bundle.


title: Perfecting the Photometric Calibration of the ACS CCD Cameras

abstract:
  Newly acquired data and improved data reduction algorithms mandate a fresh
look at the absolute flux calibration of the CCD cameras on the Hubble Space
Telescope (HST) Advanced Camera for Surveys (ACS). The goals are to achieve a
1\% accuracy and to make this calibration more accessible to the HST guest
investigator. Absolute fluxes from the
CALSPEC\footnote{http://www.stsci.edu/hst/observatory/crds/calspec.html}
database for three primary hot 30,000--60,000K WDs define the sensitivity
calibrations for the WFC and HRC filters. The external uncertainty for the
absolute flux is $\sim$1\%, while the internal consistency of the sensitivities
in the broadband ACS filters is $\sim$0.3\% among the three primary WD flux
standards. For stars as cool as K type, the agreement with the CALSPEC
standards is within 1\% at the WFC1-1K subarray position, which achieves the
1\% precision goal for the first time. After making a small adjustment to the
filter bandpass for F814W, the 1\% precision goal is achieved over the full
F814W WFC field of view for stars of K type and hotter. New encircled energies
and absolute sensitivities replace the seminal results of Sirianni et al. that
were published in 2005. After implementing the throughput updates, synthetic
predictions of the WFC and HRC count rates for the average of the three primary
WD standard stars agree with the observations to 0.1\%.


title:
A Stable Optical Trap from a Single Optical Field Utilizing
  Birefringence

abstract:
  We report a stable double optical spring effect in an optical cavity pumped
with a single optical field that arises as a result of birefringence. One end
of the cavity is formed by a multilayer Al$_{0.92}$Ga$_{0.08}$As/GaAs stack
supported by a microfabricated cantilever, with a natural mode frequency of
$274$ Hz. The optical spring shifts the resonance to $21$ kHz, corresponding to
a suppression of low frequency vibrations by a factor of more than $10^{4}$.
The stable nature of the optical trap allows the cavity to be operated without
any external feedback and with only a single optical field incident.


title:
Temporal Correlation of Interference in Bounded Mobile Ad Hoc Networks
  with Blockage

abstract:
  In mobile wireless networks with blockage, different users, and/or a single
user at different time slots, may be blocked by some common obstacles.
Therefore the temporal correlation of interference does not depend only on the
user displacement law but also on the spatial correlation introduced by the
obstacles. In this letter, we show that in mobile networks with a high density
of users, blockage increases the temporal correlation of interference, while in
sparse networks blockage has the opposite effect.


title:
Dynamic disorder, phonon lifetimes, and the assignment of modes to the
  vibrational spectra of methylammonium lead halide perovskites

abstract:
  We present Raman and terahertz absorbance spectra of methylammonium lead
halide single crystals (MAPbX3, X = I, Br, Cl) at temperatures between 80 and
370 K. These results show good agreement with density-functional-theory phonon
calculations.1 Comparison of experimental spectra and calculated vibrational
modes enables confident assignment of most of the vibrational features between
50 and 3500 cm-1. Reorientation of the methylammonium cations, unlocked in
their cavities at the orthorhombic-to-tetragonal phase transition, plays a key
role in shaping the vibrational spectra of the different compounds.
Calculations show that these dynamics effects split Raman peaks and create more
structure than predicted from the independent harmonic modes. This explains the
presence of extra peaks in the experimental spectra that have been a source of
confusion in earlier studies. We discuss singular features, in particular the
torsional vibration of the C-N axis, which is the only molecular mode that is
strongly influenced by the size of the lattice. From analysis of the spectral
linewidths, we find that MAPbI3 shows exceptionally short phonon lifetimes,
which can be linked to low lattice thermal conductivity. We show that optical
rather than acoustic phonon scattering is likely to prevail at room temperature
in these materials.


title:
Collective modes in two-dimensional one-component-plasma with
  logarithmic interaction

abstract:
  The collective modes of a familiar two-dimensional one-component-plasma with
the repulsive logarithmic interaction between the particles are analysed using
the quasi-crystalline approximation (QCA) combined with the molecular dynamic
simulation of the equilibrium structural properties. It is found that the
dispersion curves in the strongly coupled regime are virtually independent of
the coupling strength. Arguments based on the excluded volume consideration for
the radial distribution function allow us to derive very simple expressions for
the dispersion relations, which show excellent agreement with the exact QCA
dispersion over the entire domain of wavelengths. Comparison with the results
of the conventional fluid analysis is performed and the difference is
explained.


title: A note on co-Higgs bundles

abstract:
  We show that for any ample line bundle on a smooth complex projective variety
with nonnegative Kodaira dimension, the semistability of co-Higgs bundles of
implies the semistability of bundles. Then we investigate the criterion for
surface $X$ to have $H^0(T_X)=H^0(S^2T_X)=0$, which implies that any co-Higgs
structure of rank two is nilpotent.


title: Walking on the Edge and Cosystolic Expansion

abstract:
  Random walks on regular bounded degree expander graphs have numerous
applications. A key property of these walks is that they converge rapidly to
the uniform distribution on the vertices. The recent study of expansion of high
dimensional simplicial complexes, which are the high dimensional analogues of
graphs, calls for the natural generalization of random walks to higher
dimensions. In particular, a high order random walk on a $2$-dimensional
simplicial complex moves at random between neighboring edges of the complex,
where two edges are considered neighbors if they share a common triangle. We
show that if a regular $2$-dimensional simplicial complex is a cosystolic
expander and the underlying graph of the complex has a spectral gap larger than
$1/2$, then the random walk on the edges of the complex converges rapidly to
the uniform distribution on the edges.


title:
Quantum measurements, stochastic networks, the uncertainty principle,
  and not so strange "weak values"

abstract:
  The outcomes of a series of measurements, made on a quantum system, form a
sequence of random events which occur in a particular order. The system,
together with a meter or meters, can be seen as following the paths of a
stochastic network connecting all possible outcomes. The paths are shaped from
the virtual paths of the system, and the corresponding probabilities are
determined by the measuring devices employed. If the measurements are highly
accurate, the virtual paths become "real", and the mean values of a quantity (a
functional) is directly related to the frequencies with which the paths are
travelled. If the measurements are highly inaccurate, the mean (weak) values
are expressed in terms of the relative probabilities amplitudes. For pre- and
post-selected systems they are bound to take arbitrary values, depending on the
chosen transition. This is a direct consequence of the uncertainty principle,
which forbids one to distinguish between interfering alternatives, while
leaving the interference between them intact.


title:
Possibility for albedo estimation of exomoons: Why should we care about
  M dwarfs?

abstract:
  Occultation light curves of exomoons may give information on their albedo and
hence indicate the presence of ice cover on the surface. Icy moons might have
subsurface oceans thus these may potentially be habitable. The objective of our
paper is to determine whether next generation telescopes will be capable of
albedo estimations for icy exomoons using their occultation light curves. The
success of the measurements depends on the depth of the moon's occultation in
the light curve and on the sensitivity of the used instruments. We applied
simple calculations for different stellar masses in the V and J photometric
bands, and compared the flux drop caused by the moon's occultation and the
estimated photon noise of next generation missions with 5 $\sigma$ confidence.
We found that albedo estimation by this method is not feasible for moons of
solar-like stars, but small M dwarfs are better candidates for such
measurements. Our calculations in the J photometric band show that E-ELT
MICADO's photon noise is just about 4 ppm greater than the flux difference
caused by a 2 Earth-radii icy satellite in a circular orbit at the snowline of
an 0.1 stellar mass star. However, considering only photon noise underestimates
the real expected noise, because other noise sources, such as CCD read-out and
dark signal become significant in the near infrared measurements. Hence we
conclude that occultation measurements with next generation missions are far
too challenging, even in the case of large, icy moons at the snowline of small
M dwarfs. We also discuss the role of the parameters that were neglected in the
calculations, e.g. inclination, eccentricity, orbiting direction of the moon.
We predict that the first albedo estimations of exomoons will probably be made
for large icy moons around the snowline of M4 -- M9 type main sequence stars.


title:
Multimodal Compact Bilinear Pooling for Visual Question Answering and
  Visual Grounding

abstract:
  Modeling textual or visual information with vector representations trained
from large language or visual datasets has been successfully explored in recent
years. However, tasks such as visual question answering require combining these
vector representations with each other. Approaches to multimodal pooling
include element-wise product or sum, as well as concatenation of the visual and
textual representations. We hypothesize that these methods are not as
expressive as an outer product of the visual and textual vectors. As the outer
product is typically infeasible due to its high dimensionality, we instead
propose utilizing Multimodal Compact Bilinear pooling (MCB) to efficiently and
expressively combine multimodal features. We extensively evaluate MCB on the
visual question answering and grounding tasks. We consistently show the benefit
of MCB over ablations without MCB. For visual question answering, we present an
architecture which uses MCB twice, once for predicting attention over spatial
features and again to combine the attended representation with the question
representation. This model outperforms the state-of-the-art on the Visual7W
dataset and the VQA challenge.


title: Quantum state-independent contextuality requires 13 rays

abstract:
  We show that, regardless of the dimension of the Hilbert space, there exists
no set of rays revealing state-independent contextuality with less than 13
rays. This implies that the set proposed by Yu and Oh in dimension three [Phys.
Rev. Lett. 108, 030402 (2012)] is actually the minimal set in quantum theory.
This contrasts with the case of Kochen-Specker sets, where the smallest set
occurs in dimension four.


title:
Optimal Virtualized Inter-Tenant Resource Sharing for Device-to-Device
  Communications in 5G Networks

abstract:
  Device-to-Device (D2D) communication is expected to enable a number of new
services and applications in future mobile networks and has attracted
significant research interest over the last few years. Remarkably, little
attention has been placed on the issue of D2D communication for users belonging
to different operators. In this paper, we focus on this aspect for D2D users
that belong to different tenants (virtual network operators), assuming
virtualized and programmable future 5G wireless networks. Under the assumption
of a cross-tenant orchestrator, we show that significant gains can be achieved
in terms of network performance by optimizing resource sharing from the
different tenants, i.e., slices of the substrate physical network topology. To
this end, a sum-rate optimization framework is proposed for optimal sharing of
the virtualized resources. Via a wide site of numerical investigations, we
prove the efficacy of the proposed solution and the achievable gains compared
to legacy approaches.


title: Computing hyperbolic choreographies

abstract:
  An algorithm is presented for numerical computation of choreographies in
spaces of constant negative curvature in a hyperbolic cotangent potential,
extending the ideas given in a companion paper for computing choreographies in
the plane in a Newtonian potential and on a sphere in a cotangent potential.
Following an idea of Diacu, P\'{e}rez-Chavela and Reyes Victoria, we use
stereographic projection and study the problem in the Poincar\'{e} disk. Using
approximation by trigonometric polynomials and optimization methods with exact
gradient and exact Hessian matrix, we find new choreographies, hyperbolic
analogues of the ones presented in the companion paper. The algorithm proceeds
in two phases: first BFGS quasi-Newton iteration to get close to a solution,
then Newton iteration for high accuracy.


title:
Soft X-Ray Excess from Shocked Accreting Plasma in Active Galactic
  Nuclei

abstract:
  We propose a novel theoretical model to describe a physical identity of the
soft X-ray excess, ubiquitously detected in many Seyfert galaxies, by
considering a steady-state, axisymmetric plasma accretion within the innermost
stable circular orbit (ISCO) around a black hole (BH) accretion disk. We extend
our earlier theoretical investigations on general relativistic
magnetohydrodynamic (GRMHD) accretion which has implied that the accreting
plasma can develop into a standing shock for suitable physical conditions
causing the downstream flow to be sufficiently hot due to shock compression. We
numerically calculate to examine, for sets of fiducial plasma parameters, a
physical nature of fast MHD shocks under strong gravity for different BH spins.
We show that thermal seed photons from the standard accretion disk can be
effectively Compton up-scattered by the energized sub-relativistic electrons in
the hot downstream plasma to produce the soft excess feature in X-rays. As a
case study, we construct a three-parameter Comptonization model of inclination
angle $\theta_{\rm obs}$, disk photon temperature $kT_{\rm in}$ and downstream
electron energy $kT_e$ to calculate the predicted spectra in comparison with a
60 ks {\it XMM-Newton}/EPIC-pn spectrum of a typical radio-quiet Seyfert 1 AGN,
Ark~120. Our $\chi^2$-analyses demonstrate that the model is plausible in
successfully describing data for both non-spinning and spinning BHs with the
derived range of $61.3~{\rm keV} \lesssim kT_e \lesssim 144.3~{\rm keV}$,
$21.6~{\rm eV} \lesssim kT_{\rm in} \lesssim 34.0~{\rm eV}$ and $17.5\degr
\lesssim \theta_{\rm obs} \lesssim 42.6\degr$ indicating a compact Comptonizing
region of $3-4$ gravitational radii that resembles the putative X-ray coronae.


title: Gravity Tunnel Drag

abstract:
  The time it takes to fall down a tunnel through the center of the Earth to
the other side takes approximately 42 minutes, but only when given several
simplifying assumptions: a uniform density Earth; a gravitational field that
varies linearly with radial position; a non-rotating Earth; a tunnel evacuated
of air; and zero friction along the sides of the tunnel. Though several papers
have singularly relaxed the first three assumptions, in this paper we relax the
final two assumptions and analyze the motion of a body experiencing these types
of drag forces in the tunnel. Under such drag forces, we calculate the motion
of a transport vehicle through a tunnel of the Earth under uniform density,
under constant gravitational acceleration, and finally under the more realistic
Preliminary Reference Earth Model (PREM) density data. We find the density
profile corresponding to a constant gravitational acceleration better models
the motion through the tunnel compared to the PREM density profile, and the
uniform density model fares worse.


title:
Higgs mass and right-handed sneutrino WIMP in a supersymmetric 3-3-1
  model

abstract:
  This work deals with right handed sneutrino as thermal cold dark matter
candidate. This scalar emerges in a supersymmetric version of $SU(3)_c \otimes
SU(3)_L \otimes U(1)_X$ gauge model where right handed neutrinos are a natural
component of leptonic chiral scalar supermultiplets. We first consider the
issue of a $125$~GeV Higgs boson mass in this model, showing that constraints
on stop mass and trilinear soft coupling are considerably alleviated compared
to MSSM. Then we investigate the region of parameter space that is consistent
with right handed sneutrino as thermal cold dark matter, under the light of
Planck results on the relic abundance and direct detection from LUX experiment.
This sneutrino mainly annihilates through an extra neutral gauge boson,
$Z^\prime$, and Higgs exchange, so that the physics of dark matter is somewhat
related to the parameters determining Higgs and $Z^\prime$ masses. We then
obtain that right handed sneutrino in this model must be heavier than $400$~GeV
to conform with Planck and LUX, simultaneously constraining the $Z^\prime$ mass
to be above 2400~GeV, which is in perfect agreement with LHC searches in a
non-supersymmetric version of this model.


title:
Green tensor of the Stokes system and asymptotics of stationary
  Navier-Stokes flows in the half space

abstract:
  We derive refined estimates of the Green tensor of the stationary Stokes
system in the half space. We then investigate the spatial asymptotics of
stationary solutions of the incompressible Navier-Stokes equations in the half
space. We also discuss the asymptotics of fast decaying flows in the whole
space and exterior domains. In the Appendix we consider axisymmetric
self-similar solutions.


title:
Bayesian Poisson Tucker Decomposition for Learning the Structure of
  International Relations

abstract:
  We introduce Bayesian Poisson Tucker decomposition (BPTD) for modeling
country--country interaction event data. These data consist of interaction
events of the form "country $i$ took action $a$ toward country $j$ at time
$t$." BPTD discovers overlapping country--community memberships, including the
number of latent communities. In addition, it discovers directed
community--community interaction networks that are specific to "topics" of
action types and temporal "regimes." We show that BPTD yields an efficient MCMC
inference algorithm and achieves better predictive performance than related
models. We also demonstrate that it discovers interpretable latent structure
that agrees with our knowledge of international relations.


title: Hierarchical Self-Assembly of Fractals with Signal-Passing Tiles

abstract:
  In this paper, we present high-level overviews of tile-based self-assembling
systems capable of producing complex, infinite, aperiodic structures known as
discrete self-similar fractals. Fractals have a variety of interesting
mathematical and structural properties, and by utilizing the bottom-up growth
paradigm of self-assembly to create them we not only learn important techniques
for building such complex structures, we also gain insight into how similar
structural complexity arises in natural self-assembling systems. Our results
fundamentally leverage hierarchical assembly processes, and use as our building
blocks square "tile" components which are capable of activating and
deactivating their binding "glues" a constant number of times each, based only
on local interactions. We provide the first constructions capable of building
arbitrary discrete self-similar fractals at scale factor 1, and many at
temperature 1 (i.e. "non-cooperatively"), including the Sierpinski triangle.


title:
Conformal symmetry and its breaking in two dimensional Nearly
  Anti-de-Sitter space

abstract:
  We study a two dimensional dilaton gravity system, recently examined by
Almheiri and Polchinski, which describes near extremal black holes, or more
generally, nearly $AdS_2$ spacetimes. The asymptotic symmetries of $AdS_2$ are
all the time reparametrizations of the boundary. These symmetries are
spontaneously broken by the $AdS_2$ geometry and they are explicitly broken by
the small deformation away from $AdS_2$. This pattern of spontaneous plus
explicit symmetry breaking governs the gravitational backreaction of the
system. It determines several gravitational properties such as the linear in
temperature dependence of the near extremal entropy as well as the
gravitational corrections to correlation functions. These corrections include
the ones determining the growth of out of time order correlators that is
indicative of chaos. These gravitational aspects can be described in terms of a
Schwarzian derivative effective action for a reparametrization.


title:
First principles study and empirical parametrization of twisted bilayer
  MoS2 based on band-unfolding

abstract:
  We explore the band structure and ballistic electron transport in twisted
bilayer $\textrm{MoS}_2$ using Density Functional Theory (DFT). The sphagetti
like bands are unfolded to generate band structures in the primitive unit cell
of the original un-twisted $\textrm{MoS}_2$ bilayer and projected onto an
individual layer. The corresponding twist angle dependent indirect bandedges
are extracted from the unfolded band structures. Based on a comparison within
the same primitive unit cell, an efficient two band effective mass model for
indirect conduction and valence valleys is created and parameterized by fitting
the unfolded band structures. With the two band effective mass model, transport
properties - specifically, we calculate the ballistic transmission in
arbitrarily twisted bilayer $\textrm{MoS}_2$.


title: Gravitational wave detection with optical lattice atomic clocks

abstract:
  We propose a space-based gravitational wave detector consisting of two
spatially separated, drag-free satellites sharing ultra-stable optical laser
light over a single baseline. Each satellite contains an optical lattice atomic
clock, which serves as a sensitive, narrowband detector of the local frequency
of the shared laser light. A synchronized two-clock comparison between the
satellites will be sensitive to the effective Doppler shifts induced by
incident gravitational waves (GWs) at a level competitive with other proposed
space-based GW detectors, while providing complementary features. The detected
signal is a differential frequency shift of the shared laser light due to the
relative velocity of the satellites, and the detection window can be tuned
through the control sequence applied to the atoms' internal states. This scheme
enables the detection of GWs from continuous, spectrally narrow sources, such
as compact binary inspirals, with frequencies ranging from ~3 mHz - 10 Hz
without loss of sensitivity, thereby bridging the detection gap between
space-based and terrestrial optical interferometric GW detectors. Our proposed
GW detector employs just two satellites, is compatible with integration with an
optical interferometric detector, and requires only realistic improvements to
existing ground-based clock and laser technologies.

categories: physics.atom-ph astro-ph.IM gr-qc physics.optics quant-ph


title:
A Resonant Mode for Gravitational Wave Detectors based on Atom
  Interferometry

abstract:
  We describe an atom interferometric gravitational wave detector design that
can operate in a resonant mode for increased sensitivity. By oscillating the
positions of the atomic wavepackets, this resonant detection mode allows for
coherently enhanced, narrow-band sensitivity at target frequencies. The
proposed detector is flexible and can be rapidly switched between broadband and
narrow-band detection modes. For instance, a binary discovered in broadband
mode can subsequently be studied further as the inspiral evolves by using a
tailored narrow-band detector response. In addition to functioning like a
lock-in amplifier for astrophysical events, the enhanced sensitivity of the
resonant approach also opens up the possibility of searching for important
cosmological signals, including the stochastic gravitational wave background
produced by inflation. We give an example of detector parameters which would
allow detection of inflationary gravitational waves down to $\Omega_\text{GW}
\sim 10^{-14}$ for a two satellite space-based detector.

categories: physics.atom-ph astro-ph.IM gr-qc hep-th


title: Structure at infinity for shrinking Ricci solitons

abstract:
  The paper mainly concerns the structure at infinity for complete gradient
shrinking Ricci solitons. It is shown that for such a soliton with bounded
curvature, if the round cylinder $\mathbb{R}\times \mathbb{S}^{n-1}/\Gamma$
occurs as a limit for a sequence of points going to infinity along an end, then
the end is asymptotic to the same round cylinder at infinity. The result is
then applied to obtain structural results at infinity for four dimensional
gradient shrinking Ricci solitons. It is previously known that such solitons
with scalar curvature approaching zero at infinity must be smoothly asymptotic
to a cone. For the case that the scalar curvature is bounded from below by a
positive constant, we conclude that along each end the soliton is asymptotic to
a quotient of $\mathbb{R}\times \mathbb{S}^{3}$ or converges to a quotient of
$\mathbb{R}^{2}\times \mathbb{S}^{2}$ along each integral curve of the gradient
vector field of the potential function.


title:
Analysis of the $e^{+}e^{-}\rightarrow\pi^{0}\gamma$ process using
  anomaly sum rules approach

abstract:
  The process $e^{+}e^{-}\rightarrow\gamma^{*}\rightarrow \pi^{0}\gamma$ was
considered using time-like pion transition form factor, obtained in the
approach of the Anomaly Sum Rules(ASR). The total cross section and angular
distribution of the process was calculated. As the result of the comparison
with the data it was shown that ASR approach provides their good description in
the regions far from the pole. Also there was proposed a method allowing to
give reasonable description of data in the region of pole within the ASR
approach. The strong restrictions for the parameters of the modified ASR
approach were obtained.


title: Extremal particles in branching processess

abstract:
  The purpose of this study is to investigate two related spatial branching
models with the unbounded branching intensity. The objective is to describe the
asymptotic behaviour of the extremal particle.


title:
Stochastic methods for light propagation and recurrent scattering in
  saturated and nonsaturated atomic ensembles

abstract:
  We derive equations for the strongly coupled system of light and dense atomic
ensembles. The formalism includes an arbitrary internal level structure for the
atoms and is not restricted to weak excitation of atoms by light. In the low
light intensity limit for atoms with a single electronic ground state, the full
quantum field-theoretical representation of the model can be solved exactly by
means of classical stochastic electrodynamics simulations for stationary atoms
that represent cold atomic ensembles. Simulations for the optical response of
atoms in a quantum degenerate regime require one to synthesize a stochastic
ensemble of atomic positions that generates the corresponding quantum
statistical position correlations between the atoms. In the case of multiple
ground levels or at light intensities where saturation becomes important, the
classical simulations require approximations that neglect quantum fluctuations
between the levels. We show how the model is extended to incorporate
corrections due to quantum fluctuations that result from virtual scattering
processes. In the low light intensity limit we illustrate the simulations in a
system of atoms in a Mott-insulator state in a 2D optical lattice, where
recurrent scattering of light induces strong interatomic correlations. These
correlations result in collective many-atom subradiant and superradiant states
and a strong dependence of the response on the spatial confinement within the
lattice sites.

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


title:
Recurrent Neural Networks for Multivariate Time Series with Missing
  Values

abstract:
  Multivariate time series data in practical applications, such as health care,
geoscience, and biology, are characterized by a variety of missing values. In
time series prediction and other related tasks, it has been noted that missing
values and their missing patterns are often correlated with the target labels,
a.k.a., informative missingness. There is very limited work on exploiting the
missing patterns for effective imputation and improving prediction performance.
In this paper, we develop novel deep learning models, namely GRU-D, as one of
the early attempts. GRU-D is based on Gated Recurrent Unit (GRU), a
state-of-the-art recurrent neural network. It takes two representations of
missing patterns, i.e., masking and time interval, and effectively incorporates
them into a deep model architecture so that it not only captures the long-term
temporal dependencies in time series, but also utilizes the missing patterns to
achieve better prediction results. Experiments of time series classification
tasks on real-world clinical datasets (MIMIC-III, PhysioNet) and synthetic
datasets demonstrate that our models achieve state-of-the-art performance and
provides useful insights for better understanding and utilization of missing
values in time series analysis.


title: The Cornstarch Flamethrower

abstract:
  Igniting cornstarch powder is a classic physics demonstration that showcases
the rapid conduction of heat for a material in which the surface area is
greater than the volume of its constituent particles. Including such a
demonstration in a physics "magic show" for the general public presents certain
challenges such as reproducibility and consistent crowd appeal. A simple but
effective design for widely scattering cornstarch dust over a flame breaches
these challenges and always results in consistently large, crowd-pleasing
fireballs; so much so that the resulting demonstration has been dubbed the
"cornstarch flamethrower." A small-scale version may also be used effectively
for classroom instruction.


title: Questions about Boij-S\"oderberg theory

abstract:
  Boij-S\"oderberg theory focuses on the properties and duality relationship
between two types of numerical invariants. One side involves the Betti table of
a graded free resolution over the polynomial ring. The other side involves the
cohomology table of a coherent sheaf on projective space. We discuss open
questions and problems in Boij-S\"oderberg theory.


title: Unifying Count-Based Exploration and Intrinsic Motivation

abstract:
  We consider an agent's uncertainty about its environment and the problem of
generalizing this uncertainty across observations. Specifically, we focus on
the problem of exploration in non-tabular reinforcement learning. Drawing
inspiration from the intrinsic motivation literature, we use density models to
measure uncertainty, and propose a novel algorithm for deriving a pseudo-count
from an arbitrary density model. This technique enables us to generalize
count-based exploration algorithms to the non-tabular case. We apply our ideas
to Atari 2600 games, providing sensible pseudo-counts from raw pixels. We
transform these pseudo-counts into intrinsic rewards and obtain significantly
improved exploration in a number of hard games, including the infamously
difficult Montezuma's Revenge.


title: On Robustness of Kernel Clustering

abstract:
  Clustering is one of the most important unsupervised problems in machine
learning and statistics. Among many existing algorithms, kernel k-means has
drawn much research attention due to its ability to find non-linear cluster
boundaries and its inherent simplicity. There are two main approaches for
kernel k-means: SVD of the kernel matrix and convex relaxations. Despite the
attention kernel clustering has received both from theoretical and applied
quarters, not much is known about robustness of the methods. In this paper we
first introduce a semidefinite programming relaxation for the kernel clustering
problem, then prove that under a suitable model specification, both the K-SVD
and SDP approaches are consistent in the limit, albeit SDP is strongly
consistent, i.e. achieves exact recovery, whereas K-SVD is weakly consistent,
i.e. the fraction of misclassified nodes vanish.


title: Measurements of Terahertz Generation in a Metallic, Corrugated Beam Pipe

abstract:
  A method for producing narrow-band THz radiation proposes passing an
ultra-relativistic beam through a metallic pipe with small periodic
corrugations. We present results of a measurement of such an arrangement at
Brookhaven's Accelerator Test Facility (ATF). Our pipe was copper and was 5 cm
long; the aperture was cylindrically symmetric, with a 1 mm (radius) bore and a
corrugation depth (peak-to-peak) of 60 um. In the experiment we measured both
the effect on the beam of the structure wakefield and the spectral properties
of the radiation excited by the beam. We began by injecting a relatively long
beam compared to the wavelength of the radiation to excite the structure, and
then used a downstream spectrometer to infer the radiation wavelength. This was
followed by injecting a shorter bunch, and then using an interferometer (also
downstream of the corrugated pipe) to measure the spectrum of the induced THz
radiation.


title: Chimera states in two populations with heterogeneous phase-lag

abstract:
  The simplest network of coupled phase-oscillators exhibiting chimera states
is given by two populations with disparate intra- and inter-population coupling
strengths. We explore the effects of heterogeneous coupling phase-lags between
the two populations. Such heterogeneity arises naturally in various settings,
for example as an approximation to transmission delays, excitatory-inhibitory
interactions, or as amplitude and phase responses of oscillators with
electrical or mechanical coupling. We find that breaking the phase-lag symmetry
results in a variety of states with uniform and non-uniform synchronization,
including in-phase and anti-phase synchrony, full incoherence (splay state),
chimeras with phase separation of $0$ or $\pi$ between populations, and states
where both populations remain desynchronized. These desynchronized states
exhibit stable, oscillatory, and even chaotic dynamics. Moreover, we identify
the bifurcations through which chimeras emerge. Stable chimera states and
desynchronized solutions, which do not arise for homogeneous phase-lag
parameters, emerge as a result of competition between synchronized in-phase,
anti-phase equilibria, and fully incoherent states when the phase-lags are near
$\pm\frac{\pi}{2}$ (cosine coupling). These findings elucidate previous
experimental results involving a network of mechanical oscillators and provide
further insight into the breakdown of synchrony in biological systems.


title:
A Data-Driven Compressive Sensing Framework for Long-Term Health
  Monitoring

abstract:
  Compressive sensing (CS) is a promising technology for realizing
energy-efficient wireless sensors for long-term health monitoring. In this
paper, we propose a data-driven CS framework that learns signal characteristics
and individual variability from patients' data to significantly enhance CS
performance and noise resilience. This is accomplished by a co-training
approach that optimizes both the sensing matrix and dictionary towards improved
restricted isometry property (RIP) and signal sparsity, respectively.
Experimental results upon ECG signals show that our framework is able to
achieve better reconstruction quality with up to 80% higher compression ratio
(CP) than conventional frameworks based on random sensing matrices and
overcomplete bases. In addition, our framework shows great noise resilience
capability, which tolerates up to 40dB higher noise energy at a CP of 9 times.


title: Optically lightweight tracking of objects around a corner

abstract:
  The observation of objects located in inaccessible regions is a recurring
challenge in a wide variety of important applications. Recent work has shown
that indirect diffuse light reflections can be used to reconstruct objects and
two-dimensional (2D) patterns around a corner. However, these prior methods
always require some specialized setup involving either ultrafast detectors or
narrowband light sources. Here we show that occluded objects can be tracked in
real time using a standard 2D camera and a laser pointer. Unlike previous
methods based on the backprojection approach, we formulate the problem in an
analysis-by-synthesis sense. By repeatedly simulating light transport through
the scene, we determine the set of object parameters that most closely fits the
measured intensity distribution. We experimentally demonstrate that this
approach is capable of following the translation of unknown objects, and
translation and orientation of a known object, in real time.


title:
Switching field distribution of exchange coupled ferri-/ferromagnetic
  composite bit patterned media

abstract:
  We investigate the switching field distribution and the resulting bit error
rate of exchange coupled ferri-/ferromagnetic bilayer island arrays by
micromagnetic simulations. Using islands with varying microstructure and
anisotropic properties, the intrinsic switching field distribution is computed.
The dipolar contribution to the switching field distribution is obtained
separately by using a model of a triangular patterned island array resembling
$1.4\,\mathrm{Tb/in}^2$ bit patterned media. Both contributions are computed
for different thickness of the soft exchange coupled ferrimagnet and also for
ferromagnetic single phase FePt islands. A bit patterned media with a bilayer
structure of FeGd($5\,\mathrm{nm}$)/FePt($5\,\mathrm{nm}$) shows a bit error
rate of $10^{-4}$ with a write field of $1.16\,\mathrm{T}$.


title: Comparing Three Jet Rates With and Without Hadronic Rindler Horizon

abstract:
  Recently some researchers, (A. Sepehri, S. Shoorvazi, CHIN. PHYS. LETT. Vol.
30, No. 2 (2013)), have considered the effect of Rindler horizon on three jet
rate. This paper confirms their results and by comparing usual models with this
new model for different energies, shows that regarding Rindler horizon gives us
the results which more close to experimental data respect to usual models


title: Quiver varieties and crystals in symmetrizable type via modulated graphs

abstract:
  Kashiwara and Saito have a geometric construction of the infinity crystal for
any symmetric Kac-Moody algebra. The underlying set consists of the irreducible
components of Lusztig's quiver varieties, which are varieties of nilpotent
representations of a pre-projective algebra. We generalize this to
symmetrizable Kac-Moody algebras by replacing Lusztig's preprojective algebra
with a more general one due to Dlab and Ringel. In non-symmetric types we are
forced to work over non-algebraically-closed fields.