title:
The effects of external planets on inner systems: multiplicities,
  inclinations, and pathways to eccentric warm Jupiters

abstract:
  We study how close-in systems such as those detected by Kepler are affected
by the dynamics of bodies in the outer system. We consider two scenarios: outer
systems of giant planets potentially unstable to planet--planet scattering, and
wide binaries that may be capable of driving Kozai or other secular variations
of outer planets' eccentricities. Dynamical excitation of planets in the outer
system reduces the multiplicity of Kepler-detectable planets in the inner
system in $\sim20-25\%$ of our systems. Accounting for the occurrence rates of
wide-orbit planets and binary stars, $\approx18\%$ of close-in systems could be
destabilised by their outer companions in this way. This provides some
contribution to the apparent excess of systems with a single transiting planet
compared to multiple, however, it only contributes at most $25\%$ of the
excess. The effects of the outer dynamics can generate systems similar to
Kepler-56 (two coplanar planets significantly misaligned with the host star)
and Kepler-108 (two significantly non-coplanar planets in a binary). We also
identify three pathways to the formation of eccentric warm Jupiters resulting
from the interaction between outer and inner systems: direct inelastic
collision between an eccentric outer and an inner planet, secular eccentricity
oscillations that may "freeze out" when scattering resolves in the outer
system; and scattering in the inner system followed by "uplift", where inner
planets are removed by interaction with the outer planets. In these scenarios,
the formation of eccentric warm Jupiters is a signature of a past history of
violent dynamics among massive planets beyond $\sim1$ au.


title:
Polynomial Time Corresponds to Solutions of Polynomial Ordinary
  Differential Equations of Polynomial Length (Journal version)

abstract:
  The outcomes of this paper are twofold. Implicit complexity.
  We provide an implicit characterization of polynomial time computation in
terms of ordinary differential equations: we characterize the class PTIME of
languages computable in polynomial time in terms of differential equations with
polynomial right-hand side. This result gives a purely continuous elegant and
simple characterization of PTIME. We believe it is the first time complexity
classes are characterized using only ordinary differential equations. Our
characterization extends to functions computable in polynomial time over the
reals in the sense of computable analysis. Our results may provide a new
perspective on classical complexity, by giving a way to define complexity
classes, like PTIME, in a very simple way, without any reference to a notion of
(discrete) machine. This may also provide ways to state classical questions
about computational complexity via ordinary differential equations.
  Continuous-Time Models of Computation.
  Our results can also be interpreted in terms of analog computers or analog
models of computation: As a side effect, we get that the 1941 General Purpose
Analog Computer (GPAC) of Claude Shannon is provably equivalent to Turing
machines both in terms of computability and complexity, a fact that has never
been established before. This result provides arguments in favour of a
generalised form of the Church-Turing Hypothesis, which states that any
physically realistic (macroscopic) computer is equivalent to Turing machines
both in terms of computability and complexity.


title:
Center-of-mass interpretation for bipartite purity analysis of $N$-party
  entanglement

abstract:
  We provide a graphical description of the entanglement of pure-state
multiparty systems based on an analogy between a bipartite purity analysis and
the centroid of a collection of point masses. This description applies to
quantum systems with $N$ parties, each with an arbitrary number of (discrete)
states. The case of $N$ qubits is highlighted for simplicity. This geometric
description illustrates some of the restrictions in the form of inequalities
that apply to entanglement in multiparty systems.


title: Elastic Spin Hall effect in Mechanical Graphene

abstract:
  We show that spin-orbit interaction and elastic spin-Hall effect can exist in
a classical mechanical system consisting of a two-dimensional honeycomb lattice
of masses and springs. The band structure shows the presence of splitting at K
point induced by the difference of longitudinal and transverse elastic
constant, and this splitting can be regarded as an effective Dresselhaus-type
spin-orbit coupling. Interestingly, as an initial displacement away from the
equilibrium is applied, the time evolution simulation shows that waves of
different spin polarization propagates along different directions at the Gamma
and K point, which is characteristic of spin-Hall effect. Several cases for
spin-Hall effect are also discussed.


title: Fault-tolerant interface between quantum memories and quantum processors

abstract:
  Topological error correction codes are promising candidates to protect
quantum computations from the deteriorating effects of noise. While some codes
provide high noise thresholds suitable for robust quantum memories, others
allow straightforward gate implementation needed for data processing. To
exploit the particular advantages of different topological codes for
fault-tolerant quantum computation, it is necessary to be able to switch
between them. Here we propose a practical solution, subsystem lattice surgery,
which requires only two-body nearest neighbor interactions in a fixed layout in
addition to the indispensable error correction. This method can be used for the
fault-tolerant transfer of quantum information between arbitrary topological
subsystem codes in two dimensions and beyond. In particular, it can be employed
to create a simple interface, a quantum bus, between noise resilient surface
code memories and flexible color code processors.


title:
Modeling Parallel Wiener-Hammerstein Systems Using Tensor Decomposition
  of Volterra Kernels

abstract:
  Providing flexibility and user-interpretability in nonlinear system
identification can be achieved by means of block-oriented methods. One of such
block-oriented system structures is the parallel Wiener-Hammerstein system,
which is a sum of Wiener-Hammerstein branches, consisting of static
nonlinearities sandwiched between linear dynamical blocks. Parallel
Wiener-Hammerstein models have more descriptive power than their single-branch
counterparts, but their identification is a non-trivial task that requires
tailored system identification methods. In this work, we will tackle the
identification problem by performing a tensor decomposition of the Volterra
kernels obtained from the nonlinear system. We illustrate how the parallel
Wiener-Hammerstein block-structure gives rise to a joint tensor decomposition
of the Volterra kernels with block-circulant structured factors. The
combination of Volterra kernels and tensor methods is a fruitful way to tackle
the parallel Wiener-Hammerstein system identification task. In simulation
experiments, we were able to reconstruct very accurately the underlying blocks
under noisy conditions.


title: Limit theory for controlled McKean-Vlasov dynamics

abstract:
  This paper rigorously connects the problem of optimal control of
McKean-Vlasov dynamics with large systems of interacting controlled state
processes. Precisely, the empirical distributions of near-optimal control-state
pairs for the $n$-state systems, as $n$ tends to infinity, admit limit points
in distribution (if the objective functions are suitably coercive), and every
such limit is supported on the set of optimal control-state pairs for the
McKean-Vlasov problem. Conversely, any distribution on the set of optimal
control-state pairs for the McKean-Vlasov problem can be realized as a limit in
this manner. Arguments are based on controlled martingale problems, which lend
themselves naturally to existence proofs; along the way it is shown that a
large class of McKean-Vlasov control problems admit optimal Markovian controls.


title:
Equivalence and/or quantum duality of the non/supersymmetric
  noncommutative field theories related by the theta-exact Seiberg-Witten map

abstract:
  In this article we expound a discovery of the quantum equivalence/duality of
U(N) noncommutative quantum field theories (NC QFT) related by the theta-exact
Seiberg-Witten (SW) maps and at all orders in the perturbation theory with
respect to the coupling constant. We show that this proof holds for Super
Yang-Mills (SYM) theories with N=0,1,2,4$ supersymmetry. In short,
Seiberg-Witten map does commute with the quantization of the U(N) NCQFT
independently, with or without supersymmetry.


title:
Polynomial-Time Approximation for Nonconvex Optimization Problems with
  an L1-Constraint

abstract:
  Nonconvex optimization problems with an L1-constraint are ubiquitous, and are
found in many application domains including: optimal control of hybrid systems,
machine learning and statistics, and operations research. This paper shows that
nonconvex optimization problems with an L1-constraint can be approximately
solved in polynomial time. We first show that nonlinear integer programs with
an L1-constraint can be solved in a number of oracle steps that is polynomial
in the dimension of the decision variable, for each fixed radius of the
L1-constraint. When specialized to polynomial integer programs, our result
shows that such problems have a time complexity that is polynomial in
simultaneously both the dimension of the decision variables and number of
constraints, for each fixed radius of the L1-constraint. We prove this result
using a geometric argument that leverages ideas from stochastic process theory
and from the theory of convex bodies in high-dimensional spaces. We conclude by
providing an additive polynomial time approximation scheme (PTAS) for
continuous optimization of Lipschitz functions subject to Lipschitz constraints
intersected with an L1-constraint, and we sketch a generalization to
mixed-integer optimization.


title: Metrics Based on Finite Directed Graphs and Coding Invariants

abstract:
  Given a finite directed graph with $n$ vertices, we define a metric $d_G$ on
$\mathbb{F}_q^n$, where $\mathbb{F}_q$ is the finite field with $q$ elements.
The weight of a word is defined as the number of vertices that can be reached
by a directed path starting at the support of the vector. Two canonical forms,
which do not affect the metric, are given to each graph. Based on these forms
we characterize each such metric. We further use these forms to prove that two
graphs with different canonical forms yield different metrics. Efficient
algorithms to check if a set of metric weights define a metric based on a graph
are given. We provide tight bounds on the number of metric weights required to
reconstruct the metric. Furthermore, we give a complete description of the
group of linear isometries of the graph metrics and a characterization of the
graphs for which every linear code admits a $G$-canonical decomposition.
Considering those graphs, we are able to derive an expression of the packing
radius of linear codes in such metric spaces. Finally, given a directed graph
which determines a hierarchical poset, we present sufficient and necessary
conditions to ensure the validity of the MacWilliams Identity and the
MacWilliams Extension Property.


title:
Impact of non-stationary optical illumination on image reconstruction in
  optoacoustic tomography

abstract:
  Optoacoustic tomography (OAT), also known as photoacoustic tomography, is a
rapidly emerging hybrid imaging technique that possesses great potential for a
wide range of biomedical imaging applications. In OAT, a laser is employed to
illuminate the tissue of interest and acoustic signals are produced via the
photoacoustic effect. From these data, an estimate of the distribution of the
absorbed optical energy density within the tissue is reconstructed, referred to
as the object function. This quantity is defined, in part, by the distribution
of light fluence within the tissue that is established by the laser source.
When performing three-dimensional imaging of large objects, such as a female
human breast, it can be difficult to achieve a relatively uniform coverage of
light fluence within the volume of interest when the position of the laser
source is fixed. To circumvent this, researchers have proposed illumination
schemes in which the relative position of the laser source and ultrasound probe
is fixed, and both are rotated together to acquire a tomographic data set. A
problem with this rotating-illumination scheme is that the tomographic data are
inconsistent; namely, the acoustic data recorded at each tomographic view angle
(i.e., probe position) are produced by a distinct object function. In this
work, the impact of this data inconsistency on image reconstruction accuracy is
investigated systematically. This is accomplished by use of computer-simulation
studies and application of mathematical results from the theory of microlocal
analysis. These studies specify the set of image discontinuities that can be
stably reconstructed with a non-stationary optical illumination set-up. The
study also includes a comparison of the ability of iterative and analytic image
reconstruction methods to mitigate artifacts attributable to the data
inconsistency.


title: Connecting VLBI and Gaia celestial reference frames

abstract:
  The current state of the link problem between radio and optical celestial
reference frames is considered. The main objectives of the investigations in
this direction during the next few years are the preparation of a comparison
and the mutual orientation and rotation between the optical {\it Gaia}
Celestial Reference Frame (GCRF) and the 3rd generation radio International
Celestial Reference Frame (ICRF3), obtained from VLBI observations. Both
systems, ideally, should be a realization of the ICRS (International Celestial
Reference System) at micro-arcsecond level accuracy. Therefore, the link
accuracy between the ICRF and GCRF should be obtained with similar error level,
which is not a trivial task due to relatively large systematic and random
errors in source positions at different frequency bands. In this paper, a brief
overview of recent work on the GCRF--ICRF link is presented. Additional
possibilities to improve the GCRF--ICRF link accuracy are discussed. The
suggestion is made to use astrometric radio sources with optical magnitude to
20$^m$ rather than to 18$^m$ as currently planned for the GCRF--ICRF link. In
addition, the use of radio stars is also a prospective method to obtain
independent and accurate orientation between the Gaia frame and the ICRF.


title:
The projective cover of the trivial representation for a finite group of
  Lie type in defining characteristic

abstract:
  We give a lower bound of the Loewy length of the projective cover of the
trivial module for the group algebra $kG$ of a finite group $G$ of Lie type
defined over a finite field of odd characteristic $p$, where $k$ is an
arbitrary field of characteristic $p$; the proof uses Auslander-Reiten theory.


title:
Localization of supersymmetric field theories on non-compact hyperbolic
  three-manifolds

abstract:
  We study supersymmetric gauge theories with an R-symmetry, defined on
non-compact, hyperbolic, Riemannian three-manifolds, focusing on the case of a
supersymmetry-preserving quotient of Euclidean AdS$_3$. We compute the exact
partition function in these theories, using the method of localization, thus
reducing the problem to the computation of one-loop determinants around a
supersymmetric locus. We evaluate the one-loop determinants employing three
different techniques: an index theorem, the method of pairing of eigenvalues,
and the heat kernel method. Along the way, we discuss aspects of supersymmetry
in manifolds with a conformal boundary, including supersymmetric actions and
boundary conditions.


title: A brief introduction to Spectral Graph Theory

abstract: Expanded lecture notes. Preliminary version, comments are welcome.


title:
On non-polynomial lower error bounds for adaptive strong approximation
  of SDEs

abstract:
  Recently, it has been shown in [Hairer, M., Hutzenthaler, M., Jentzen, A.,
Loss of regularity for Kolmogorov equations, Ann. Probab. 43, 2 (2015),
468--527] that there exists a system of stochastic differential equations (SDE)
on the time interval $[0,T]$ with infinitely often differentiable and bounded
coefficients such that the Euler scheme with equidistant time steps converges
to the solution of this SDE at the final time in the strong sense but with no
polynomial rate. Even worse, in [Jentzen, A., M\"uller-Gronbach, T., and
Yaroslavtseva, L. On stochastic differential equations with arbitrary slow
convergence rates for strong approximation, Commun. Math. Sci. 14, 7 (2016),
1477-1500] it has been shown that for any sequence $(a_n)_{n\in\mathbb
N}\subset (0,\infty)$, which may converge to zero arbitrary slowly, there
exists an SDE on $[0,T]$ with infinitely often differentiable and bounded
coefficients such that no approximation of the solution of this SDE at the
final time based on $n$ evaluations of the driving Brownian motion at fixed
time points can achieve a smaller absolute mean error than the given number
$a_n$. In the present article we generalize the latter result to the case when
the approximations may choose the location as well as the number of the
evaluation sites of the driving Brownian motion in an adaptive way dependent on
the values of the Brownian motion observed so far.


title: Orientation Statistics and Quantum Information

abstract:
  Motivated by the engineering applications of uncertainty quantification, in
this work we draw connections between the notions of random quantum states and
operations in quantum information with probability distributions commonly
encountered in the field of orientation statistics. This approach identifies
natural probability distributions that can be used in the analysis, simulation,
and inference of quantum information systems. The theory of exponential
families on Stiefel manifolds provides the appropriate generalization to the
classical case, and fortunately there are many existing techniques for
inference and sampling that exist for these distributions. Furthermore, this
viewpoint motivates a number of additional questions into the convex geometry
of quantum operations relative to both the differential geometry of Stiefel
manifolds as well as the information geometry of exponential families defined
upon them. In particular, we draw on results from convex geometry to
characterize which quantum operations can be represented as the average of a
random quantum operation.


title:
S-MART: Novel Tree-based Structured Learning Algorithms Applied to Tweet
  Entity Linking

abstract:
  Non-linear models recently receive a lot of attention as people are starting
to discover the power of statistical and embedding features. However,
tree-based models are seldom studied in the context of structured learning
despite their recent success on various classification and ranking tasks. In
this paper, we propose S-MART, a tree-based structured learning framework based
on multiple additive regression trees. S-MART is especially suitable for
handling tasks with dense features, and can be used to learn many different
structures under various loss functions.
  We apply S-MART to the task of tweet entity linking --- a core component of
tweet information extraction, which aims to identify and link name mentions to
entities in a knowledge base. A novel inference algorithm is proposed to handle
the special structure of the task. The experimental results show that S-MART
significantly outperforms state-of-the-art tweet entity linking systems.


title: Review: Local Integrals of Motion in Many-Body Localized systems

abstract:
  We review the current (as of Fall 2016) status of the studies on the emergent
integrability in many-body localized models. We start by explaining how the
phenomenology of fully many-body localized systems can be recovered if one
assumes the existence of a complete set of (quasi)local operators which commute
with the Hamiltonian (local integrals of motion, or LIOMs). We describe the
evolution of this idea from the initial conjecture, to the perturbative
constructions, to the mathematical proof given for a disordered spin chain. We
discuss the proposed numerical algorithms for the construction of LIOMs and the
status of the debate on the existence and nature of such operators in systems
with a many-body mobility edge, and in dimensions larger than one.


title: Derived A-infinity algebras and their homotopies

abstract:
  The notion of a derived A-infinity algebra, considered by Sagave, is a
generalization of the classical notion of A-infinity algebra, relevant to the
case where one works over a commutative ring rather than a field. We initiate a
study of the homotopy theory of these algebras, by introducing a hierarchy of
notions of homotopy between the morphisms of such algebras. We define
r-homotopy, for non-negative integers r, in such a way that r-homotopy
equivalences underlie E_r-quasi-isomorphisms, defined via an associated
spectral sequence. We study the special case of twisted complexes (also known
as multicomplexes) first since it is of independent interest and this simpler
case clearly exemplifies the structure we study. We also give two new
interpretations of derived A-infinity algebras as A-infinity algebras in
twisted complexes and as A-infinity algebras in split filtered cochain
complexes.


title:
Robust Regression For Image Binarization Under Heavy Noises and
  Nonuniform Background

abstract:
  This paper presents a robust regression approach for image binarization under
significant background variations and observation noises. The work is motivated
by the need of identifying foreground regions in noisy microscopic image or
degraded document images, where significant background variation and severe
noise make an image binarization challenging. The proposed method first
estimates the background of an input image, subtracts the estimated background
from the input image, and apply a global thresholding to the subtracted outcome
for achieving a binary image of foregrounds. A robust regression approach was
proposed to estimate the background intensity surface with minimal effects of
foreground intensities and noises, and a global threshold selector was proposed
on the basis of a model selection criterion in a sparse regression. The
proposed approach was validated using 26 test images and the corresponding
ground truths, and the outcomes of the proposed work were compared with those
from nine existing image binarization methods. The approach was also combined
with three state-of-the-art morphological segmentation methods to show how the
proposed approach can improve their image segmentation outcomes.


title: Properties of the multiway discrepancy

abstract:
  Some properties of the multiway discrepanc of rectangular matrices of
nonnegative entries are discussed. We are able to prove the continuity of this
discrepancy, as well as some statements about the multiway discrepancy of some
special matrices and graphs. We also conjecture that the k-way discrepancy is
monotonic in k.


title: Swipe Mosaics from Video

abstract:
  A panoramic image mosaic is an attractive visualization for viewing many
overlapping photos, but its images must be both captured and processed
correctly to produce an acceptable composite. We propose Swipe Mosaics, an
interactive visualization that places the individual video frames on a 2D
planar map that represents the layout of the physical scene. Compared to
traditional panoramic mosaics, our capture is easier because the user can both
translate the camera center and film moving subjects. Processing and display
degrade gracefully if the footage lacks distinct, overlapping, non-repeating
texture. Our proposed visual odometry algorithm produces a distribution over
(x,y) translations for image pairs. Inferring a distribution of possible camera
motions allows us to better cope with parallax, lack of texture, dynamic
scenes, and other phenomena that hurt deterministic reconstruction techniques.
Robustness is obtained by training on synthetic scenes with known camera
motions. We show that Swipe Mosaics are easy to generate, support a wide range
of difficult scenes, and are useful for documenting a scene for closer
inspection.


title: Electron - positron cascades in multiple-laser optical traps

abstract:
  We present an analytical and numerical study of multiple-laser QED cascades
induced with linearly polarised laser pulses. We analyse different polarisation
orientations and propose a configuration that maximises the cascade
multiplicity and favours the laser absorption. We generalise the analytical
estimate for the cascade growth rate previously calculated in the field of two
colliding linearly polarised laser pulses and account for multiple laser
interaction. The estimate is verified by a comprehensive numerical study of
four-laser QED cascades across a range of different laser intensities with QED
PIC module of OSIRIS. We show that by using four linearly polarised 30 fs laser
pulses, one can convert more than 50 % of the total energy to gamma-rays
already at laser intensity $I\simeq10^{24}\ \mathrm{W/cm^2}$. In this
configuration, the laser conversion efficiency is higher compared with the case
with two colliding lasers.


title: An Ontology of Preference-Based Multiobjective Metaheuristics

abstract:
  User preference integration is of great importance in multi-objective
optimization, in particular in many objective optimization. Preferences have
long been considered in traditional multicriteria decision making (MCDM) which
is based on mathematical programming. Recently, it is integrated in
multi-objective metaheuristics (MOMH), resulting in focus on preferred parts of
the Pareto front instead of the whole Pareto front. The number of publications
on preference-based multi-objective metaheuristics has increased rapidly over
the past decades. There already exist various preference handling methods and
MOMH methods, which have been combined in diverse ways. This article proposes
to use the Web Ontology Language (OWL) to model and systematize the results
developed in this field. A review of the existing work is provided, based on
which an ontology is built and instantiated with state-of-the-art results. The
OWL ontology is made public and open to future extension. Moreover, the usage
of the ontology is exemplified for different use-cases, including querying for
methods that match an engineering application, bibliometric analysis, checking
existence of combinations of preference models and MOMH techniques, and
discovering opportunities for new research and open research questions.


title:
The multiplicity of memory enhancement: Practical and ethical
  implications of the diverse neural substrates underlying human memory systems

abstract:
  The neural basis of human memory is incredibly complex. We argue that the
diversity of neural systems underlying various forms of memory suggests that
any discussion of enhancing 'memory' per se is too broad, thus obfuscating the
biopolitical debate about human enhancement. Memory can be differentiated into
at least four major (and several minor) systems with largely dissociable (i.e.,
non-overlapping) neural substrates. We outline each system, and discuss both
the practical and the ethical implications of these diverse neural substrates.
In practice, distinct neural bases imply the possibility, and likely the
necessity, of specific approaches for the safe and effective enhancement of
various memory systems. In the debate over the ethical and social implications
of enhancement technologies, this fine-grained perspective clarifies - and may
partially mitigate - certain common concerns in enhancement debates, including
issues related to safety, fairness, coercion, and authenticity. While many
researchers certainly appreciate the neurobiological complexity of memory, the
political debate tends to revolve around a monolithic one-size-fits-all
conception. The overall project - exploring how human enhancement technologies
affect society - stands to benefit from a deeper appreciation of memory's
neurobiological diversity.


title:
Toward Socially-Infused Information Extraction: Embedding Authors,
  Mentions, and Entities

abstract:
  Entity linking is the task of identifying mentions of entities in text, and
linking them to entries in a knowledge base. This task is especially difficult
in microblogs, as there is little additional text to provide disambiguating
context; rather, authors rely on an implicit common ground of shared knowledge
with their readers. In this paper, we attempt to capture some of this implicit
context by exploiting the social network structure in microblogs. We build on
the theory of homophily, which implies that socially linked individuals share
interests, and are therefore likely to mention the same sorts of entities. We
implement this idea by encoding authors, mentions, and entities in a continuous
vector space, which is constructed so that socially-connected authors have
similar vector representations. These vectors are incorporated into a neural
structured prediction model, which captures structural constraints that are
inherent in the entity linking task. Together, these design decisions yield F1
improvements of 1%-5% on benchmark datasets, as compared to the previous
state-of-the-art.


title: Electron and phonon transport in shandite-structured Ni$_3$Sn$_2$S$_2$

abstract:
  The shandite family of solids, with hexagonal structure and composition
A3M2X2 (A = Ni,Co,Rh,Pd; M = Pb,In,Sn,Tl; X = S,Se), has attracted recent
research attention due to promising applications as thermoelectric materials.
Herein we discuss the electron and phonon transport properties of
shandite-structured Ni3Sn2S2, based on a combination of density functional
theory (DFT), Boltzmann transport theory, and experimental measurements.
Ni3Sn2S2 exhibits a metallic and non-magnetic groundstate with Ni$^0$ oxidation
state and very low charge on Sn and S atoms. Seebeck coefficients obtained from
theoretical calculations are in excellent agreement with those measured
experimentally between 100 and 600 K. From the calculation of the ratio
$\sigma$/$\tau$ between the electronic conductivity and relaxation time, and
the experimental determination of electron conductivity, we extract the
variation of the scattering rate (1/$\tau$) with temperature between 300 and
600 K, which turns out to be almost linear, thus implying that the dominant
electron scattering mechanism in this temperature range is via phonons. The
electronic thermal conductivity, which deviates only slightly from the
Wiedemann-Franz law, provides the main contribution to thermal transport. The
small lattice contribution to the thermal conductivity is calculated from the
phonon structure and third-order force constants, and is only ~2
Wm$^{-1}$K$^{-1}$ at 300 K (less than 10% of the total thermal conductivity),
which is confirmed by experimental measurements. Overall, Ni$_3$Sn$_2$S$_2$ is
a poor thermoelectric material (ZT~0.01 at 300 K), principally due to the low
absolute value of the Seebeck coefficient. However, the understanding of its
transport properties will be useful for the rationalization of the
thermoelectric behavior of other, more promising members of the shandite
family.


title: Dynamical Systems and Sheaves

abstract:
  A categorical framework for modeling and analyzing systems in a broad sense
is proposed. These systems should be thought of as `machines' with inputs and
outputs, carrying some sort of signal that occurs through some notion of time.
Special cases include continuous and discrete dynamical systems (e.g. Moore
machines). Additionally, morphisms between the different types of systems allow
their translation in a common framework. A central goal is to understand the
systems that result from arbitrary interconnection of component subsystems,
possibly of different types, as well as establish conditions that ensure
totality and determinism compositionally. The fundamental categorical tools
used here include lax monoidal functors, which provide a language of
compositionality, as well as sheaf theory, which flexibly captures the crucial
notion of time.


title: On the Rationality of Nagaraj-Seshadri Moduli Space

abstract:
  We show that each of the irreducible components of moduli of rank 2
torsion-free sheaves with odd Euler characteristic over a reducible nodal curve
is rational.


title: Fluctuations of Two-Dimensional Coulomb Gases

abstract:
  We prove a Central Limit Theorem for the linear statistics of two-dimensional
Coulomb gases, with arbitrary inverse temperature and general confining
potential, at the macroscopic and mesoscopic scales and possibly near the
boundary of the support of the equilibrium measure. This can be stated in terms
of convergence of the random electrostatic potential to a Gaussian Free Field.
  Our result is the first to be valid at arbitrary temperature and at the
mesoscopic scales, and we recover previous results of Ameur-Hendenmalm-Makarov
and Rider-Vir\'ag concerning the determinantal case, with weaker assumptions
near the boundary. We also prove moderate deviations upper bounds, or rigidity
estimates, for the linear statistics and a convergence result for those
corresponding to energy-minimizers.
  The method relies on a change of variables, a perturbative expansion of the
energy, and the comparison of partition functions deduced from our previous
work. Near the boundary, we use recent quantitative stability estimates on the
solutions to the obstacle problem obtained by Serra and the second author.


title:
Software Platforms for Smart Cities: Concepts, Requirements, Challenges,
  and a Unified Reference Architecture

abstract:
  Making cities smarter help improve city services and increase citizens'
quality of life. Information and communication technologies (ICT) are
fundamental for progressing towards smarter city environments. Smart City
software platforms potentially support the development and integration of Smart
City applications. However, the ICT community must overcome current significant
technological and scientific challenges before these platforms can be widely
used. This paper surveys the state-of-the-art in software platforms for Smart
Cities. We analyzed 23 projects with respect to the most used enabling
technologies, as well as functional and non-functional requirements,
classifying them into four categories: Cyber-Physical Systems, Internet of
Things, Big Data, and Cloud Computing. Based on these results, we derived a
reference architecture to guide the development of next-generation software
platforms for Smart Cities. Finally, we enumerated the most frequently cited
open research challenges, and discussed future opportunities. This survey gives
important references for helping application developers, city managers, system
operators, end-users, and Smart City researchers to make project, investment,
and research decisions.


title: Nonclassicality of local bipartite correlations

abstract:
  Simulating quantum nonlocality and steering requires augmenting pre-shared
randomness with non-vanishing communication cost. This prompts the question of
how one may provide such an operational characterization for the quantumness of
correlations due even to unentangled states. Here we show that for a certain
class of states, such quantumness can be pointed out by superlocality, the
requirement for a larger dimension of the pre-shared randomness to simulate the
correlations than that of the quantum state that generates them. This provides
an approach to define the nonclassicality of local multipartite correlations in
convex operational theories.


title:
H.E.S.S. limits on line-like dark matter signatures in the 100 GeV to 2
  TeV energy range close to the Galactic Centre

abstract:
  A search for dark matter line-like signals was performed in the vicinity of
the Galactic Centre by the H.E.S.S. experiment on observational data taken in
2014. An unbinned likelihood analysis was developed to improve the sensitivity
to line-like signals. The upgraded analysis along with newer data extend the
energy coverage of the previous measurement down to 100 GeV. The 18 h of data
collected with the H.E.S.S. array allow one to rule out at 95% CL the presence
of a 130 GeV line (at $l = -1.5^{\circ}, b = 0^{\circ}$ and for a dark matter
profile centered at this location) previously reported in Fermi-LAT data. This
new analysis overlaps significantly in energy with previous Fermi-LAT and
H.E.S.S. results. No significant excess associated with dark matter
annihilations was found in the energy range 100 GeV to 2 TeV and upper limits
on the gamma-ray flux and the velocity weighted annihilation cross-section are
derived adopting an Einasto dark matter halo profile. Expected limits for
present and future large statistics H.E.S.S. observations are also given.


title:
How much can we trust high-resolution spectroscopic stellar atmospheric
  parameters?

abstract:
  The determination of atmospheric parameters depends on the use of radiative
transfer codes (among other elements such as model atmospheres) to compute
synthetic spectra and/or derive abundances from equivalent widths. However, it
is common to mix results from different surveys/studies where different setups
were used to derive the parameters. These inhomogeneities can lead us to
inaccurate conclusions. In this work, we studied one aspect of the problem:
When deriving atmospheric parameters from high-resolution stellar spectra, what
differences originate from the use of different radiative transfer codes?


title: The effect of matter structure on the gravitational waveform

abstract:
  Third generation ground-based interferometers as well as the planned
space-based interferometer LISA are expected to detect a plethora of
gravitational wave signals from coalescing binaries at cosmological distance.
The emitted gravitational waves propagate in the expanding universe through the
inhomogeneous distribution of matter. Here we show that the acceleration of the
universe and the peculiar acceleration of the binary with respect to the
observer distort the gravitational chirp signal from the simplest General
Relativity prediction beyond a mere time independent rescaling of the chirp
mass, affecting intrinsic parameter estimations for the binaries visible by
LISA. We find that the effect due to the peculiar acceleration can be much
larger than the one due to the universe acceleration. Moreover, peculiar
accelerations can introduce a bias in the estimation of parameters such as the
time of coalescence and the individual masses of the binary. An error in the
estimation of the arrival time will have an impact in the case of sources
visible first by LISA and later by ground based interferometers.


title:
Efficient and portable acceleration of quantum chemical many-body
  methods in mixed floating point precision using OpenACC compiler directives

abstract:
  It is demonstrated how the non-proprietary OpenACC standard of compiler
directives may be used to compactly and efficiently accelerate the
rate-determining steps of two of the most routinely applied many-body methods
of electronic structure theory, namely the second-order M{\o}ller-Plesset (MP2)
model in its resolution-of-the-identity (RI) approximated form and the (T)
triples correction to the coupled cluster singles and doubles model (CCSD(T)).
By means of compute directives as well as the use of optimized device math
libraries, the operations involved in the energy kernels have been ported to
graphics processing unit (GPU) accelerators, and the associated data transfers
correspondingly optimized to such a degree that the final implementations
(using either double and/or single precision arithmetics) are capable of
scaling to as large systems as allowed for by the capacity of the host central
processing unit (CPU) main memory. The performance of the hybrid CPU/GPU
implementations is assessed through calculations on test systems of alanine
amino acid chains using one-electron basis sets of increasing size (ranging
from double- to pentuple-zeta quality). For all but the smallest problem sizes
of the present study, the optimized accelerated codes (using a single
multi-core CPU host node in conjunction with six GPUs) are found to be capable
of reducing the total time-to-solution by at least an order of magnitude over
optimized, OpenMP-threaded CPU-only reference implementations.


title:
How much does a treedepth modulator help to obtain polynomial kernels
  beyond sparse graphs?

abstract:
  In the last years, kernelization with structural parameters has been an
active area of research within the field of parameterized complexity. As a
relevant example, Gajarsk{\`y} et al. [ESA 2013] proved that every graph
problem satisfying a property called finite integer index admits a linear
kernel on graphs of bounded expansion and an almost linear kernel on nowhere
dense graphs, parameterized by the size of a $c$-treedepth modulator, which is
a vertex set whose removal results in a graph of treedepth at most $c$, where
$c \geq 1$ is a fixed integer. The authors left as further research to
investigate this parameter on general graphs, and in particular to find
problems that, while admitting polynomial kernels on sparse graphs, behave
differently on general graphs.
  In this article we answer this question by finding two very natural such
problems: we prove that Vertex Cover admits a polynomial kernel on general
graphs for any integer $c \geq 1$, and that Dominating Set does not for any
integer $c \geq 2$ even on degenerate graphs, unless $\text{NP} \subseteq
\text{coNP}/\text{poly}$. For the positive result, we build on the techniques
of Jansen and Bodlaender [STACS 2011], and for the negative result we use a
polynomial parameter transformation for $c\geq 3$ and an OR-cross-composition
for $c = 2$. As existing results imply that Dominating Set admits a polynomial
kernel on degenerate graphs for $c = 1$, our result provides a dichotomy about
the existence of polynomial kernels for Dominating Set on degenerate graphs
with this parameter.


title:
Chiral study of the $a_0(980)$ resonance and $\pi\eta$ scattering phase
  shifts in light of a recent lattice simulation

abstract:
  We investigate the $a_0(980)$ resonance within chiral effective field theory
through a three-coupled-channel analysis, namely $\pi\eta$, $K\bar{K}$ and
$\pi\eta'$. A global fit to recent lattice finite-volume energy levels from
$\pi\eta$ scattering and relevant experimental data on a $\pi\eta$ event
distribution and the $\gamma\gamma\to\pi\eta$ cross section is performed. Both
the leading and next-to-leading-order analyses lead to similar and successful
descriptions of the finite-volume energy levels and the experimental data.
However, these two different analyses yield different $\pi\eta$ scattering
phase shifts for the physical masses for the $\pi, K, \eta$ and $\eta'$ mesons.
The inelasticities, the pole positions in the complex energy plane and their
residues are calculated both for unphysical and physical meson masses.


title:
Creating Causal Embeddings for Question Answering with Minimal
  Supervision

abstract:
  A common model for question answering (QA) is that a good answer is one that
is closely related to the question, where relatedness is often determined using
general-purpose lexical models such as word embeddings. We argue that a better
approach is to look for answers that are related to the question in a relevant
way, according to the information need of the question, which may be determined
through task-specific embeddings. With causality as a use case, we implement
this insight in three steps. First, we generate causal embeddings
cost-effectively by bootstrapping cause-effect pairs extracted from free text
using a small set of seed patterns. Second, we train dedicated embeddings over
this data, by using task-specific contexts, i.e., the context of a cause is its
effect. Finally, we extend a state-of-the-art reranking approach for QA to
incorporate these causal embeddings. We evaluate the causal embedding models
both directly with a casual implication task, and indirectly, in a downstream
causal QA task using data from Yahoo! Answers. We show that explicitly modeling
causality improves performance in both tasks. In the QA task our best model
achieves 37.3% P@1, significantly outperforming a strong baseline by 7.7%
(relative).


title:
Estimates for the number of eigenvalues of two dimensional Schroedinger
  operators lying below the essential spectrum

abstract:
  The celebrated Cwikel-Lieb_Rozenblum inequality gives an upper estimate for
the number of negative eigenvalues of Schroedinger operators in dimension three
and higher. The situation is much more difficult in the two dimensional case.
There has been significant progress in obtaining upper estimates for the number
of negative eigenvalues of two dimensional Schroedinger operators on the whole
plane. In this thesis, we present estimates of the Cwikel-Lieb_Rozenblum type
for the number of eigenvalues (counted with multiplicities) of two dimensional
Schroedinger operators lying below the essential spectrum in terms of the norms
of the potential. The problem is considered on the whole plane with different
supports of the potential of dimension between 0 and 2, and on a strip with
various boundary conditions. In both cases, the estimates involve weighted L^1
norms and Orlicz norms of the potential.


title:
Wavy membranes and the growth rate of a planar chemical garden: Enhanced
  diffusion and bioenergetics

abstract:
  In order to model ion transport across protocell membranes in Hadean
hydrothermal vents, we consider both theoretically and experimentally the
planar growth of a precipitate membrane formed at the interface between two
parallel fluid streams in a two-dimensional microfluidic reactor. The growth
rate of the precipitate is found to be proportional to the square root of time,
which is characteristic of diffusive transport. However, the dependence of the
growth rate on the concentrations of hydroxide and metal ions is approximately
linear and quadratic, respectively. We show that such a difference in ionic
transport dynamics arises from the enhanced transport of metal ions across a
thin gel layer present at the surface of the precipitate. The fluctuations in
transverse velocity in this wavy porous gel layer allow an enhanced transport
of the cation, so that the effective diffusivity is about an order of magnitude
higher than that expected from molecular diffusion alone. Our theoretical
predictions are in excellent agreement with our laboratory measurements of the
growth of a manganese hydroxide membrane in a microfluidic channel, and this
enhanced transport is thought to have been needed to account for the
bioenergetics of the first single-celled organisms.

categories: nlin.AO cond-mat.soft physics.bio-ph q-bio.SC


title: On Divisors of Modular Forms

abstract:
  The denominator formula for the Monster Lie algebra is the product expansion
for the modular function $j(z)-j(\tau)$ given in terms of the Hecke system of
$\operatorname{SL}_2(\mathbb Z)$-modular functions $j_n(\tau)$. It is prominent
in Zagier's seminal paper on traces of singular moduli, and in the
Duncan-Frenkel work on Moonshine. The formula is equivalent to the description
of the generating function for the $j_n(z)$ as a weight 2 modular form with a
pole at $z$. Although these results rely on the fact that $X_0(1)$ has genus 0,
here we obtain a generalization, framed in terms of polar harmonic Maass forms,
for all of the $X_0(N)$ modular curves. We use these functions to study
divisors of modular forms.


title:
Adaptive Euler-Maruyama Method for SDEs with Non-globally Lipschitz
  Drift: Part I, Finite Time Interval

abstract:
  This paper proposes an adaptive timestep construction for an Euler-Maruyama
approximation of SDEs with a drift which is not globally Lipschitz. It is
proved that if the timestep is bounded appropriately, then over a finite time
interval the numerical approximation is stable, and the expected number of
timesteps is finite. Furthermore, the order of strong convergence is the same
as usual, i.e. order one-half for SDEs with a non-uniform globally Lipschitz
volatility, and order one for Langevin SDEs with unit volatility and a drift
with sufficient smoothness. The analysis is supported by numerical experiments
for a variety of SDEs.


title: Improved quasi parton distribution through Wilson line renormalization

abstract:
  Recent developments showed that hadron light-cone parton distributions could
be directly extracted from spacelike correlators, known as quasi parton
distributions, in the large hadron momentum limit. Unlike the normal light-cone
parton distribution, a quasi parton distribution contains ultraviolet (UV)
power divergence associated with the Wilson line self energy. We show that to
all orders in the coupling expansion, the power divergence can be removed by a
"mass" counterterm in the auxiliary $z$-field formalism, in the same way as the
renormalization of power divergence for an open Wilson line. After adding this
counterterm, the quasi quark distribution is improved such that it contains at
most logarithmic divergences. Based on a simple version of discretized gauge
action, we present the one-loop matching kernel between the improved
non-singlet quasi quark distribution with a lattice regulator and the
corresponding quark distribution in dimensional regularization.


title: Quantum Circuits for Quantum Channels

abstract:
  We study the implementation of quantum channels with quantum computers while
minimizing the experimental cost, measured in terms of the number of
Controlled-NOT (C-NOT) gates required (single-qubit gates are free). We
consider three different models. In the first, the Quantum Circuit Model (QCM),
we consider sequences of single-qubit and C-NOT gates and allow qubits to be
traced out at the end of the gate sequence. In the second (RandomQCM), we also
allow external classical randomness. In the third (MeasuredQCM) we also allow
measurements followed by operations that are classically controlled on the
outcomes. We prove lower bounds on the number of C-NOT gates required and give
near-optimal decompositions in almost all cases. Our main result is a
MeasuredQCM circuit for any channel from m qubits to n qubits that uses at most
one ancilla and has a low C-NOT count. We give explicit examples for small
numbers of qubits that provide the lowest known C-NOT counts.


title: Inducing Superconducting Correlation in Quantum Hall Edge States

abstract:
  The quantum Hall (QH) effect supports a set of chiral edge states at the
boundary of a 2-dimensional electron gas (2DEG) system. A superconductor (SC)
contacting these states induces correlation of the quasi-particles in the
dissipationless 1D chiral QH edge states. If the superconducting electrode is
narrower than the superconducting coherence length, the incoming electron are
correlated to outgoing hole along the chiral edge state by the Andreev process.
In order to realize this crossed Andreev conversion (CAC), it is necessary to
fabricate highly transparent and nanometer-scale superconducting junctions to
QH system. Here we report the observation of CAC in a graphene QH system
contacted with a nanostructured NbN superconducting electrode. The chemical
potential of the edge states across the superconducting electrode exhibits a
sign reversal, providing direct evidence of CAC. This hybrid SC/QH system is a
novel route to create isolated non-Abelian anyonic zero modes, in resonance
with the chiral QH edge.


title:
Classical and quantum dynamics of a charged scalar particle in a
  background of two counterpropagating plane waves

abstract:
  We consider a scalar particle in a background formed by two
counter-propagating plane waves. Two cases are studied: i) dynamics at a
magnetic node and ii) zero initial transverse canonical momentum. The Lorentz
and Klein-Gordon equations are solved for these cases and approximations
analysed. For the magnetic node solution (homogeneous, time-dependent electric
field), the modified Volkov wavefunction which arises from a high-energy
approximation is found to be inaccurate for all energies and the solution
itself unstable when photon emission (nonlinear Compton scattering) is
included. For the zero initial transverse canonical momentum case, in both
quantum and classical cases, forbidden parameter regimes, absent in the plane
wave model, are identified.

categories: quant-ph hep-ph physics.class-ph physics.plasm-ph


title:
Patterns in Inversion Sequences II: Inversion Sequences Avoiding Triples
  of Relations

abstract:
  Inversion sequences of length $n$, $\mathbf{I}_n$, are integer sequences
$(e_1, \ldots, e_n)$ with $0 \leq e_i < n$ for each $i$. The study of patterns
in inversion sequences was initiated recently by Mansour-Shattuck and
Corteel-Martinez-Savage-Weselcouch through a systematic study of inversion
sequences avoiding words of length 3. We continue this investigation by
generalizing the notion of a pattern to a fixed triple of binary relations
$(\rho_1,\rho_2,\rho_3)$ and consider the set
$\mathbf{I}_n(\rho_1,\rho_2,\rho_3)$ consisting of those $e \in \mathbf{I}_n$
with no $i < j < k$ such that $e_i \rho_1 e_j$, $e_j \rho_2 e_k$, and $e_i
\rho_3 e_k$. We show that "avoiding a triple of relations" can characterize
inversion sequences with a variety of monotonicity or unimodality conditions,
or with multiplicity constraints on the elements. We uncover several
interesting enumeration results and relate pattern avoiding inversion sequences
to familiar combinatorial families. We highlight open questions about the
relationship between pattern avoiding inversion sequences and families such as
plane permutations and Baxter permutations. For several combinatorial
sequences, pattern avoiding inversion sequences provide a simpler
interpretation than otherwise known.


title: On One-dimensional Multi-Particle Diffusion Limited Aggregation

abstract:
  We prove that the one dimensional Multi-Particle Diffusion Limited
Aggregation model has linear growth whenever the particle density exceeds 1
answering a question of Kesten and Sidoravicius. As a corollary we prove linear
growth in all dimensions d when the particle density is at least 1.


title:
Mathematical models of SIR disease spread with combined non-sexual and
  sexual transmission routes

abstract:
  The emergence of diseases such as Zika and Ebola has highlighted the need to
understand the role of sexual transmission in the spread of diseases with a
primarily non-sexual transmission route. In this paper we develop a number of
low-dimensional models which are appropriate for a range of assumptions for how
a disease will spread if it has sexual transmission through a sexual contact
network combined with some other transmission mechanism, such as direct contact
or vectors. The equations derived provide exact predictions for the dynamics of
the corresponding simulations in the large population limit.


title: Ultra-low threshold polariton condensation

abstract:
  We demonstrate condensation of microcavity polaritons with a very sharp
threshold occuring at two orders of magnitude lower pump intensity than
previous demonstrations of condensation. The long cavity-lifetime and trapping
and pumping geometries are crucial to the realization of this low threshold.
Polariton condensation, or "polariton lasing" has long been proposed as a
promising source of coherent light at lower threshold than traditional lasing,
and these results suggest methods to bring this threshold even lower.


title: Dynamically hot Super-Earths from outer giant planet scattering

abstract:
  The hundreds of multiple planetary systems discovered by the \textit{Kepler}
mission are typically observed to reside in close-in ($\lesssim0.5$ AU),
low-eccentricity, and low-inclination orbits. We run N-body experiments to
study the effect that unstable outer ($\gtrsim1$ AU) giant planets, whose end
orbital configurations resemble those in the Radial Velocity population, have
on these close-in multiple super-Earth systems. Our experiments show that the
giant planets greatly reduce the multiplicity of the inner super-Earths and the
surviving population can have large eccentricities ($e\gtrsim0.3$) and
inclinations ($i\gtrsim20^\circ$) at levels that anti-correlate with
multiplicity. Consequently, this model predicts the existence of a population
of dynamically hot single-transiting planets with typical eccentricities and
inclinations %in the ranges of $\sim 0.1-0.5$ and $\sim 10^\circ-40^\circ$. We
show that these results can explain the following observations: (i) the recent
eccentricity measurements of \textit{Kepler} super-Earths from transit
durations; (ii) the tentative observation that single-transiting systems have a
wider distribution of stellar obliquity angles compared to the
multiple-transiting systems; (iii) the architecture of some eccentric
super-Earths discovered by Radial Velocity surveys such as HD\,125612c. Future
observations from \textit{TESS} will reveal many more dynamically hot single
transiting planets, for which follow up Radial Velocity studies will be able to
test our models and see whether they have outer giant planets.


title: The Tail Asymptotics of the Brownian Signature

abstract:
  The signature of a path \gamma is a sequence whose n-th term is the order-n
iterated integrals of \gamma. It arises from solving multidimensional linear
differential equations driven by \gamma. We are interested in relating the path
properties of \gamma with its signature. If \gamma is C^{1}, then an elegant
formula of Hambly and Lyons relates the length of \gamma to the tail
asymptotics of the signature. We show an analogous formula for the
multidimensional Brownian motion, with the quadratic variation playing a
similar role to the length. In the proof, we study the hyperbolic development
of Brownian motion and also obtain a new subadditive estimate for the
asymptotic of signature, which may be of independent interest. As a corollary,
we strengthen the existing uniqueness results for the signatures of Brownian
motion.


title:
Nonnoetherian homotopy dimer algebras and noncommutative crepant
  resolutions

abstract:
  Noetherian dimer algebras form a prominent class of examples of
noncommutative crepant resolutions (NCCRs). However, dimer algebras which are
noetherian are quite rare, and we consider the question: how close are
nonnoetherian homotopy dimer algebras to being NCCRs? To address this question,
we introduce a generalization of NCCRs to nonnoetherian tiled matrix rings. We
show that if a noetherian dimer algebra is obtained from a nonnoetherian
homotopy dimer algebra $A$ by contracting each arrow whose head has indegree 1,
then $A$ is a noncommutative desingularization of its nonnoetherian center.
Furthermore, if any two arrows whose tails have indegree 1 are coprime, then
$A$ is a nonnoetherian NCCR.


title: Topology optimized permanent magnet systems

abstract:
  Topology optimization of permanent magnet systems consisting of permanent
magnets, high permeability iron and air is presented. An implementation of
topology optimization for magnetostatics is discussed and three examples are
considered. First, the Halbach cylinder is topology optimized with iron and an
increase of 15% in magnetic efficiency is shown, albeit with an increase of 3.8
pp. in field inhomogeneity - a value compared to the inhomogeneity in a 16
segmented Halbach cylinder. Following this a topology optimized structure to
concentrate a homogeneous field is shown to increase the magnitude of the field
by 111% for the chosen dimensions. Finally, a permanent magnet with alternating
high and low field regions is considered. Here a $\Lambda_\mathrm{cool}$ figure
of merit of 0.472 is reached, which is an increase of 100% compared to a
previous optimized design.


title: Solving Batched Linear Programs on GPU and Multicore CPU

abstract:
  Linear Programs (LPs) appear in a large number of applications and offloading
them to the GPU is viable to gain performance. Existing work on offloading and
solving an LP on GPU suggests that performance is gained from large sized LPs
(typically 500 constraints, 500 variables and above). In order to gain
performance from GPU for applications involving small to medium sized LPs, we
propose batched solving of a large number of LPs in parallel. In this paper, we
present the design and CUDA implementation of our batched LP solver library,
keeping memory coalescent access, reduced CPU-GPU memory transfer latency and
load balancing as the goals. The performance of the batched LP solver is
compared against sequential solving in the CPU using an open source solver GLPK
(GNU Linear Programming Kit). The performance is evaluated for three types of
LPs. The first type is the initial basic solution as feasible, the second type
is the initial basic solution as infeasible and the third type is the feasible
region as a Hyperbox. For the first type, we show a maximum speedup of
$18.3\times$ when running a batch of $50k$ LPs of size $100$ ($100$ variables,
$100$ constraints). For the second type, a maximum speedup of $12\times$ is
obtained with a batch of $10k$ LPs of size $200$. For the third type, we show a
significant speedup of $63\times$ in solving a batch of nearly $4$ million LPs
of size 5 and $34\times$ in solving 6 million LPs of size $28$. In addition, we
show that the open source library for solving linear programs-GLPK, can be
easily extended to solve many LPs in parallel with multi-threading. The thread
parallel GLPK implementation runs $9.6\times$ faster in solving a batch of
$1e5$ LPs of size $100$, on a $12$-core Intel Xeon processor. We demonstrate
the application of our batched LP solver in the domain of state-space
exploration of mathematical models of control systems design.


title: Quantum anomalous Hall effect in ferromagnetic transition metal halides

abstract:
  The quantum anomalous Hall (QAH) effect is a novel topological spintronic
phenomenon arising from inherent magnetization and spin-orbit coupling. Various
theoretical and experimental efforts have been devoted in search of robust
intrinsic QAH insulators. However, up to now, it has only been observed in Cr
or V doped (Bi,Sb)2Te3 film in experiments with very low working temperature.
Based on the successful synthesis of transition metal halides, we use
first-principles calculations to predict that RuI3 monolayer is an intrinsic
ferromagnetic QAH insulator with a topologically nontrivial global band gap of
11 meV. This topologically nontrivial band gap at the Fermi level is due to its
crystal symmetry, thus the QAH effect is robust. Its Curie temperature,
estimated to be ~360 K using Monte-Carlo simulation, is above room temperature
and higher than most of two-dimensional ferromagnetic thin films. We also
discuss the manipulation of its exchange energy and nontrivial band gap by
applying in-plane strain. Our work adds a new experimentally feasible member to
the QAH insulator family, which is expected to have broad applications in
nanoelectronics and spintronics.


title:
Predictive Positioning and Quality Of Service Ridesharing for Campus
  Mobility On Demand Systems

abstract:
  Autonomous Mobility On Demand (MOD) systems can utilize fleet management
strategies in order to provide a high customer quality of service (QoS).
Previous works on autonomous MOD systems have developed methods for rebalancing
single capacity vehicles, where QoS is maintained through large fleet sizing.
This work focuses on MOD systems utilizing a small number of vehicles, such as
those found on a campus, where additional vehicles cannot be introduced as
demand for rides increases. A predictive positioning method is presented for
improving customer QoS by identifying key locations to position the fleet in
order to minimize expected customer wait time. Ridesharing is introduced as a
means for improving customer QoS as arrival rates increase. However, with
ridesharing perceived QoS is dependent on an often unknown customer preference.
To address this challenge, a customer ratings model, which learns customer
preference from a 5-star rating, is developed and incorporated directly into a
ridesharing algorithm. The predictive positioning and ridesharing methods are
applied to simulation of a real-world campus MOD system.A combined predictive
positioning and ridesharing approach is shown to reduce customer service times
by up to 29% and the customer ratings model is shown to provide the best
overall MOD fleet management performance over a range of customer preferences.


title:
Power Talk for Multibus DC MicroGrids: Creating and Optimizing
  Communication Channels

abstract:
  We study a communication framework for nonlinear multibus DC MicroGrids based
on a deliberate modification of the parameters of the primary control and
termed power talk. We assess the case in which the information is modulated in
the deviations of reference voltages of the primary control loops and show that
the outputs of the power talk communication channels can be approximated
through linear combinations of the respective inputs. We show that the
coefficients of the linear combinations, representing equivalent channel gains,
depend on the virtual resistances of the primary control loops, implying that
they can be modified such that effective received signal-to-noise ratio (SNR)
is increased. On the other hand, we investigate the constraints that power talk
incurs on the supplied power deviations. We show that these constraints
translate into constraints on the reference voltages and virtual resistances
that are imposed on all units in the system. In this regard, we develop an
optimization approach to find the set of controllable virtual resistances that
maximize SNR under the constraints on the supplied power deviations.


title: Inverse Transport and Acousto-Optic Imaging

abstract:
  We consider the inverse problem of recovering the optical properties of a
highly-scattering medium from acousto-optic measurements. Using such
measurements, we show that the scattering and absorption coefficients of the
radiative transport equation can be reconstructed with Lipschitz stability by
means of algebraic inversion formulas.


title: Effect of Pauli blocking on coherent states of composite bosons

abstract:
  The quantum nature of elementary bosons can be completely erased by using
coherent states known as Glauber states. Here, we consider composite bosons
(cobosons) made of two fermions and look for the possibility to erase the
bosonic quantum nature of the field and the fermionic quantum nature of its
constituents, when the distribution of the coboson Schmidt decomposition is
either flat like Frenkel excitons, or localized like Wannier excitons. We show
that for Frenkel-like cobosons, complete erasure of the field quantum nature is
possible up to a density which corresponds to a sizable fraction of the number
of fermion-pair states making the coboson at hand. At higher density, the Pauli
exclusion principle between fermionic constituents shows up dramatically. It
induces: (i) the decrease of number-operator eigenvalues down to 1 and the
increase of the number-state second-order correlation function up to 2; (ii)
the disappearance of the usual sharp peak in the coherent-state distribution
and the increase of the coherent-state second-order correlation function up to
2. It also is possible to construct number states and coherent states for
Wannier-like cobosons, but their forms are far more complex. Finally, we show
that Pauli blocking makes the coboson coherent states qualitatively different
from the Anderson's ansatz.


title:
Observations and simulations of the Na I D1 line profiles in an M-class
  solar flare

abstract:
  We study the temporal evolution of the Na I D1 line profiles in the M3.9
flare SOL2014-06-11T21:03 UT, using high spectral resolution observations
obtained with the IBIS instrument on the Dunn Solar Telescope combined with
radiative hydrodynamic simulations. Our results show a significant increase in
line core and wing intensities during the flare. The analysis of the line
profiles from the flare ribbons reveal that the Na I D1 line has a central
reversal with excess emission in the blue wing (blue asymmetry). We combine
RADYN and RH simulations to synthesise Na I D1 line profiles of the flaring
atmosphere and find good agreement with the observations. Heating with a beam
of electrons modifies the radiation field in the flaring atmosphere and excites
electrons from the ground state $\mathrm{3s~^2S}$ to the first excited state
$\mathrm{3p~^2P}$, which in turn modifies relative population of the two
states. The change in temperature and the population density of the energy
states make the sodium line profile revert from absorption into emission.
Analysis of the simulated spectra also reveals that the Na I D1 flare profile
asymmetries are produced by the velocity gradients generated %and opacity
effects in the lower solar atmosphere.


title: Improving the Randomization Step in Feasibility Pump

abstract:
  Feasibility pump (FP) is a successful primal heuristic for mixed-integer
linear programs (MILP). The algorithm consists of three main components:
rounding fractional solution to a mixed-integer one, projection of infeasible
solutions to the LP relaxation, and a randomization step used when the
algorithm stalls. While many generalizations and improvements to the original
Feasibility Pump have been proposed, they mainly focus on the rounding and
projection steps.
  We start a more in-depth study of the randomization step in Feasibility Pump.
For that, we propose a new randomization step based on the WalkSAT algorithm
for solving SAT instances. First, we provide theoretical analyses that show the
potential of this randomization step; to the best of our knowledge, this is the
first time any theoretical analysis of running-time of Feasibility Pump or its
variants has been conducted. Moreover, we also conduct computational
experiments incorporating the proposed modification into a state-of-the-art
Feasibility Pump code that reinforce the practical value of the new
randomization step.


title: On Shahidi local coefficients matrix

abstract:
  In these notes we define and study the Shahidi local coefficients matrix
associated with a genuine principal series representation I({\sigma}) of an
n-fold cover of p-adic SL(2,F) and an additive character {\psi}. The conjugacy
class of this matrix is an invariant of the inducing representation {\sigma}
and {\psi} and its entries are linear combinations of Tate or Tate type
{\gamma}-factors. We relate these entries to functional equations associated
with linear maps defined on the dual of the space of Schwartz functions. As an
application we give new formulas for the Plancherel measure and use these to
relate principal series representations of different coverings of SL(2,F).
While we do not assume that the residual characteristic of F is relatively
prime to n we do assume that n is not divisible by 4.


title:
Strong Equivalence Principle in Polymer Quantum Mechanics and deformed
  Heisenberg Algebra

abstract:
  The Strong equivalence Principle (SEP) states that the description of a
physical system in a gravitational field is indistinguishable from the
description of the same system at rest in an accelerating frame. While this
statement holds true in both General Relativity and ordinary Quantum Mechanics,
one expects it to fail when quantum gravity corrections are taken into account.
In this paper we investigate the possible failure of the SEP in two Quantum
Gravity inspired modifications of Quantum Mechanics - Polymer Quantum Mechanics
and deformed Heisenberg Algebra. We find that the SEP fails to hold in both
these theories. We estimate the deviation from SEP and find in both cases that
it is too small to be measured in present day experiments.


title:
Learning Language-Visual Embedding for Movie Understanding with
  Natural-Language

abstract:
  Learning a joint language-visual embedding has a number of very appealing
properties and can result in variety of practical application, including
natural language image/video annotation and search. In this work, we study
three different joint language-visual neural network model architectures. We
evaluate our models on large scale LSMDC16 movie dataset for two tasks: 1)
Standard Ranking for video annotation and retrieval 2) Our proposed movie
multiple-choice test. This test facilitate automatic evaluation of
visual-language models for natural language video annotation based on human
activities. In addition to original Audio Description (AD) captions, provided
as part of LSMDC16, we collected and will make available a) manually generated
re-phrasings of those captions obtained using Amazon MTurk b) automatically
generated human activity elements in "Predicate + Object" (PO) phrases based on
"Knowlywood", an activity knowledge mining model. Our best model archives
Recall@10 of 19.2% on annotation and 18.9% on video retrieval tasks for subset
of 1000 samples. For multiple-choice test, our best model achieve accuracy
58.11% over whole LSMDC16 public test-set.


title:
A Good-Lambda Lemma, two weight T1 theorems without weak boundedness,
  and a two weight accretive global Tb theorem

abstract:
  The weak boundedness property associated with a standard alpha-fractional
Calderon-Zygmund operator and a weight pair is good-lambda controlled by the
testing conditions and the Muckenhoupt and energy side conditions. As a
consequence, assuming the side conditions, we can eliminate the weak
boundedness property from Theorem 1 of arXiv:1603.04332v2 to obtain that T is
bounded if and only if the testing conditions hold for T and its dual (an
earlier instance of this type of conclusion appears in Lacey and Wick
arXiv:1312.6163v3). As a corollary we give a simple derivation of a two weight
accretive global Tb theorem from a related T1 theorem. The role of two
different parameterizations of the family of dyadic grids, by scale and by
translation, is highlighted in simultaneously exploiting both goodness and NTV
surgery with families of grids that are common to both measures.


title: Genuine-multipartite entanglement criteria based on positive maps

abstract:
  Positive maps applied to a subsystem of a bipartite quantum state constitute
a central tool in characterising entanglement. In the multipartite case,
however, the direct application of a positive but not completely positive map
cannot distinguish if a state is genuinely multipartite entangled or just
entangled across some bipartition. We thus generalise this bipartite concept to
the multipartite setting by introducing non-positive maps that are positive on
the subset of bi-separable states, but can map to a non-positive element if
applied to a genuine multipartite entangled state. We explicitly construct
examples of multipartite non-positive maps, obtained from positive maps via a
lifting procedure, that in this fashion can reveal genuine multipartite
entanglement in a robust way.


title: Prospects for three-body Higgs boson decays into extra light scalars

abstract:
  Within models containing a very light scalar particle coupled to the 125 GeV
Higgs boson, we present the first detailed study of Higgs decays into three of
these light scalars. We determine model-independent conditions which the scalar
sector after electroweak symmetry breaking has to satisfy in order for the
three-body channel to become relevant. Using a specific model -- the real
scalar singlet-extension of the Standard Model (SM) -- we then identify
scenarios, where the rates of scalar three-body Higgs decays are comparable to
or even exceed those of the well-studied two-body channel. All those scenarios
are shown to be compatible with current experimental and theoretical
constraints. We finally argue that scalar three-body Higgs decays lead to
exciting new collider signatures with six SM fermions in the final state.
Calculating the corresponding event rates, we find that e.g. six-muon or
six-tau final states may be in reach of dedicated searches at the LHC or ILC
experiments.


title: On rigid compact complex surfaces and manifolds

abstract:
  This article investigates the subject of rigid compact complex manifolds.
First of all we investigate the different notions of rigidity (local rigidity,
global rigidity, infinitesimal rigidity, etale rigidity and strong rigidity)
and the relations among them. Only for curves these notions coincide and the
only rigid curve is the projective line.
  For surfaces we prove that a rigid surface which is not minimal of general
type is either a Del Pezzo surface of degree >= 5 or an Inoue surface. We give
examples of rigid manifolds of dimension n >= 3 and Kodaira dimensions 0, and 2
<=k <= n. Our main theorem is that the Hirzebruch Kummer coverings of exponent
n >= 4 branched on a complete quadrangle are infinitesimally rigid. Moreover,
we pose a number of questions.


title:
Supersymmetric $U(1)_{Y^{\prime}}\otimes U(1)_{B-L}$ extension of the
  standard model

abstract:
  We build a supersymmetric version with $SU(3)_C\otimes SU(2)_L\otimes
U(1)_{Y^\prime}\otimes U(1)_{B-L}$ gauge symmetry, where $Y^\prime$ is a new
charge and $B$ and $L$ are the usual baryonic and leptonic numbers. The model
has three right-handed neutrinos with identical $B-L$ charges, and can
accommodate all fermion masses at the tree level. In particular, the type-I
seesaw mechanism is implemented for the generation of the active neutrino
masses. We obtain the mass spectra of all sectors and for the scalar one we
also give the flat directions allowed by the model.


title: A recursive skeletonization factorization based on strong admissibility

abstract:
  We introduce the strong recursive skeletonization factorization (RS-S), a new
approximate matrix factorization based on recursive skeletonization for solving
discretizations of linear integral equations associated with elliptic partial
differential equations in two and three dimensions (and other matrices with
similar hierarchical rank structure). Unlike previous skeletonization-based
factorizations, RS-S uses a simple modification of skeletonization, strong
skeletonization, which compresses only far-field interactions. This leads to an
approximate factorization in the form of a product of many block
unit-triangular matrices that may be used as a preconditioner or
moderate-accuracy direct solver, with dramatically reduced rank growth. We
further combine the strong skeletonization procedure with alternating
near-field compression to obtain the hybrid recursive skeletonization
factorization (RS-WS), a modification of RS-S that exhibits reduced storage
cost in many settings. Under suitable rank assumptions both RS-S and RS-WS
exhibit linear computational complexity, which we demonstrate with a number of
numerical examples.


title:
Probing the dynamic structure factor of a neutral Fermi superfluid along
  the BCS-BEC crossover using atomic impurity qubits

abstract:
  We study an impurity atom trapped by an anharmonic potential, immersed within
a cold atomic Fermi gas with attractive interactions that realizes the
crossover from a Bardeen-Cooper-Schrieffer (BCS) superfluid to a Bose-Einstein
condensate (BEC). Considering the qubit comprising the lowest two vibrational
energy eigenstates of the impurity, we demonstrate that its dynamics probes the
equilibrium density fluctuations encoded in the dynamic structure factor of the
superfluid. Observing the impurity's evolution is thus shown to facilitate
nondestructive measurements of the superfluid order parameter and the contact
between collective and single-particle excitation spectra. Our setup
constitutes a novel model of an open quantum system interacting with a thermal
reservoir, the latter supporting both bosonic and fermionic excitations that
are also coupled to each other.


title: Order-preserving 1-string representations of planar graphs

abstract:
  This paper considers 1-string representations of planar graphs that are
order-preserving in the sense that the order of crossings along the curve
representing vertex $v$ is the same as the order of edges in the clockwise
order around $v$ in the planar embedding. We show that this does not exist for
all planar graphs (not even for all planar 3-trees), but show existence for
some subclasses of planar partial 3-trees. In particular, for outer-planar
graphs it can be order-preserving and outer-string in the sense that all ends
of strings are on the outside of the representation.


title:
Anisotropic heat conduction in silicon nanowire network revealed by
  Raman scattering

abstract:
  Anisotropic nanomaterials possess interesting thermal transport properties
because they allow orientation of heat fluxes along preferential directions due
to a high ratio (up to three orders of magnitude) between their in-plane and
cross-plane thermal conductivities. Among different techniques allowing thermal
conductivity evaluation, micro-Raman scattering is known to be one of the most
efficient contactless measurement approaches. In this letter, a new
experimental approach based on Raman scattering measurements with variable
laser spot sizes is reported. Correlation between experimental and calculated
thermal resistances of one-dimensional nanocrystalline solids allows
simultaneous estimation of their in-plane and cross-plane thermal
conductivities. In particular, our measurement approach is illustrated to be
successfully applied for anisotropic thermal conductivity evaluation of silicon
nanowire arrays.


title: Classical enhancement of quantum vacuum fluctuations

abstract:
  We propose a mechanism for the enhancement of vacuum fluctuations by means of
a classical field. The basic idea is that if an observable quantity depends
quadratically upon a quantum field, such as the electric field, then the
application of a classical field produces a cross term between the classical
and quantum fields. This cross term may be significantly larger than the purely
quantum part, but also undergoes fluctuations driven by the quantum field. We
illustrate this effect in a model for lightcone fluctuations involving pulses
in a nonlinear dielectric. Vacuum electric field fluctuations produce
fluctuations in the speed of a probe pulse, and form an analog model for
quantum gravity effects. If the material has a nonzero third-order
susceptibility, then the fractional light speed fluctuations are proportional
to the square of the fluctuating electric field. Hence the application of a
classical electric field can enhance the speed fluctuations. We give an example
where this enhancement can be an increase of one order of magnitude, increasing
the possibility of observing the effect.


title: Physics Of Eclipsing Binaries. II. Towards the Increased Model Fidelity

abstract:
  The precision of photometric and spectroscopic observations has been
systematically improved in the last decade, mostly thanks to space-borne
photometric missions and ground-based spectrographs dedicated to finding
exoplanets. The field of eclipsing binary stars strongly benefited from this
development. Eclipsing binaries serve as critical tools for determining
fundamental stellar properties (masses, radii, temperatures and luminosities),
yet the models are not capable of reproducing observed data well either because
of the missing physics or because of insufficient precision. This led to a
predicament where radiative and dynamical effects, insofar buried in noise,
started showing up routinely in the data, but were not accounted for in the
models. PHOEBE (PHysics Of Eclipsing BinariEs; http://phoebe-project.org) is an
open source modeling code for computing theoretical light and radial velocity
curves that addresses both problems by incorporating missing physics and by
increasing the computational fidelity. In particular, we discuss triangulation
as a superior surface discretization algorithm, meshing of rotating single
stars, light time travel effect, advanced phase computation, volume
conservation in eccentric orbits, and improved computation of local intensity
across the stellar surfaces that includes photon-weighted mode, enhanced limb
darkening treatment, better reflection treatment and Doppler boosting. Here we
present the concepts on which PHOEBE is built on and proofs of concept that
demonstrate the increased model fidelity.


title: Resilience for the Littlewood-Offord Problem

abstract:
  Consider the sum $X(\xi)=\sum_{i=1}^n a_i\xi_i$, where $a=(a_i)_{i=1}^n$ is a
sequence of non-zero reals and $\xi=(\xi_i)_{i=1}^n$ is a sequence of i.i.d.
Rademacher random variables (that is, $\Pr[\xi_i=1]=\Pr[\xi_i=-1]=1/2$). The
classical Littlewood-Offord problem asks for the best possible upper bound on
the concentration probabilities $\Pr[X=x]$. In this paper we study a resilience
version of the Littlewood-Offord problem: how many of the $\xi_i$ is an
adversary typically allowed to change without being able to force concentration
on a particular value? We solve this problem asymptotically, and present a few
interesting open problems.


title:
Nearest-Neighbor and Contact Distance Distributions for Thomas Cluster
  Process

abstract:
  We characterize the statistics of nearest-neighbor and contact distance
distributions for Thomas cluster process (TCP), which is a special case of
Poisson cluster process. In particular, we derive the cumulative distribution
function (CDF) of the distance to the nearest point of TCP from a reference
point for three different cases: (i) reference point is not a part of the point
process, (ii) it is chosen uniformly at random from the TCP, and (iii) it is a
randomly chosen point from a cluster chosen uniformly at random from the TCP.
While the first corresponds to the contact distance distribution, the other two
provide two different viewpoints for the nearest-neighbor distance
distribution.


title: The Capacity of Private Information Retrieval from Coded Databases

abstract:
  We consider the problem of private information retrieval (PIR) over a
distributed storage system. The storage system consists of $N$ non-colluding
databases, each storing a coded version of $M$ messages. In the PIR problem,
the user wishes to retrieve one of the available messages without revealing the
message identity to any individual database. We derive the
information-theoretic capacity of this problem, which is defined as the maximum
number of bits of the desired message that can be privately retrieved per one
bit of downloaded information. We show that the PIR capacity in this case is
$C=\left(1+\frac{K}{N}+\frac{K^2}{N^2}+\cdots+\frac{K^{M-1}}{N^{M-1}}\right)^{-1}=(1+R_c+R_c^2+\cdots+R_c^{M-1})^{-1}=\frac{1-R_c}{1-R_c^M}$,
where $R_c$ is the rate of the $(N,K)$ code used. The capacity is a function of
the code rate and the number of messages only regardless of the explicit
structure of the storage code. The result implies a fundamental tradeoff
between the optimal retrieval cost and the storage cost. The result generalizes
the achievability and converse results for the classical PIR with replicating
databases to the case of coded databases.


title:
An Unsupervised Probability Model for Speech-to-Translation Alignment of
  Low-Resource Languages

abstract:
  For many low-resource languages, spoken language resources are more likely to
be annotated with translations than with transcriptions. Translated speech data
is potentially valuable for documenting endangered languages or for training
speech translation systems. A first step towards making use of such data would
be to automatically align spoken words with their translations. We present a
model that combines Dyer et al.'s reparameterization of IBM Model 2
(fast-align) and k-means clustering using Dynamic Time Warping as a distance
metric. The two components are trained jointly using expectation-maximization.
In an extremely low-resource scenario, our model performs significantly better
than both a neural model and a strong baseline.


title:
Maximal functions associated to flat plane curves with Mitigating
  factors

abstract:
  We study the boundedness problem for maximal operators $\mathbb{M}_{\sigma}$
associated to flat plane curves with Mitigating factors, defined by
$$\mathbb{M}_{\sigma}f(x) \, := \, \sup_{1 \leq t \leq 2} \left|\int_{0}^{1}
f(x-t\Gamma(s)) \, (\kappa(s))^{\sigma} \, ds\right|,$$ where $\kappa(s)$
denotes the curvature of the curve $\Gamma(s)=(s, g(s)+1), ~g(s) \in C^5[0,1]$
in $\mathbb{R}^2$. Let $\triangle$ be the closed triangle with vertices
$P=(\frac{2}{5}, \frac{1}{5}), ~ Q=(\frac{1}{2}, \frac{1}{2}), ~ R=(0, 0).$
  In this paper, we prove that for $ (\frac{1}{p}, \frac{1}{q}) \in
\left[(\frac{1}{p}, \frac{1}{q}) :(\frac{1}{p}, \frac{1}{q}) \in \triangle
\setminus \{P, Q\} \right] \cap \left[(\frac{1}{p}, \frac{1}{q}) :q >
max\{\sigma^{-1},2\} \right]$, there is a constant $B$ such that $
\|\mathbb{M}f\|_{L^q(\mathbb{R}^2)} \leq \, B \, \|f\|_{L^p(\mathbb{R}^2)}. $


title:
On-Demand Routing Algorithm with Mobility Prediction in the Mobile
  Ad-hoc Networks

abstract:
  In this paper, we propose an ad-hoc on-demand distance vector routing
algorithm for mobile ad-hoc networks taking into account node mobility.
Changeable topology of such mobile ad-hoc networks provokes overhead messages
in order to search available routes and maintain found routes. The overhead
messages impede data delivery from sources to destination and deteriorate
network performance. To overcome such a challenge, our proposed algorithm
estimates link duration based neighboring node mobility and chooses the most
reliable route. The proposed algorithm also applies the estimate for route
maintenance to lessen the number of overhead messages. Via simulations, the
proposed algorithm is verified in various mobile environments. In the low
mobility environment, by reducing route maintenance messages, the proposed
algorithm significantly improves network performance such as packet data rate
and end-to-end delay. In the high mobility environment, the reduction of route
discovery message enhances network performance since the proposed algorithm
provides more reliable routes.


title:
Measuring quantum entanglement, machine learning and wave function
  tomography: Bridging theory and experiment with the quantum gas microscope

abstract:
  There is an enormous amount of information that can be extracted from the
data of a quantum gas microscope that has yet to be fully explored. The quantum
gas microscope has been used to directly measure magnetic order, dynamic
correlations, Pauli blocking, and many other physical phenomena in several
recent groundbreaking experiments. However, the analysis of the data from a
quantum gas microscope can be pushed much further, and when used in conjunction
with theoretical constructs it is possible to measure virtually any observable
of interest in a wide range of systems. We focus on how to measure quantum
entanglement in large interacting quantum systems. In particular, we show that
quantum gas microscopes can be used to measure the entanglement of interacting
boson systems exactly, where previously it had been thought this was only
possible for non-interacting systems. We consider algorithms that can work for
large experimental data sets which are similar to theoretical variational Monte
Carlo techniques, and more data limited sets using properties of correlation
functions.

categories: cond-mat.str-el cond-mat.dis-nn cond-mat.quant-gas quant-ph


title: CMB Delensing Beyond the B Modes

abstract:
  Gravitational lensing by large-scale structure significantly impacts
observations of the cosmic microwave background (CMB): it smooths the acoustic
peaks in temperature and $E$-mode polarization power spectra, correlating
previously uncorrelated modes; and it converts $E$-mode polarization into
$B$-mode polarization. The act of measuring and removing the effect of lensing
from CMB maps, or delensing, has been well studied in the context of $B$ modes,
but little attention has been given to the delensing of the temperature and $E$
modes. In this paper, we model the expected delensed $T$ and $E$ power spectra
to all orders in the lensing potential, demonstrating the sharpening of the
acoustic peaks and a significant reduction in lens-induced power spectrum
covariances. We then perform cosmological forecasts, demonstrating that
delensing will yield improved sensitivity to parameters with upcoming surveys.
We highlight the breaking of the degeneracy between the effective number of
neutrino species and primordial helium fraction as a concrete application. We
also show that delensing increases cosmological information as long as the
measured lensing reconstruction is included in the analysis. We conclude that
with future data, delensing will be crucial not only for primordial $B$-mode
science but for a range of other observables as well.


title:
Google's Neural Machine Translation System: Bridging the Gap between
  Human and Machine Translation

abstract:
  Neural Machine Translation (NMT) is an end-to-end learning approach for
automated translation, with the potential to overcome many of the weaknesses of
conventional phrase-based translation systems. Unfortunately, NMT systems are
known to be computationally expensive both in training and in translation
inference. Also, most NMT systems have difficulty with rare words. These issues
have hindered NMT's use in practical deployments and services, where both
accuracy and speed are essential. In this work, we present GNMT, Google's
Neural Machine Translation system, which attempts to address many of these
issues. Our model consists of a deep LSTM network with 8 encoder and 8 decoder
layers using attention and residual connections. To improve parallelism and
therefore decrease training time, our attention mechanism connects the bottom
layer of the decoder to the top layer of the encoder. To accelerate the final
translation speed, we employ low-precision arithmetic during inference
computations. To improve handling of rare words, we divide words into a limited
set of common sub-word units ("wordpieces") for both input and output. This
method provides a good balance between the flexibility of "character"-delimited
models and the efficiency of "word"-delimited models, naturally handles
translation of rare words, and ultimately improves the overall accuracy of the
system. Our beam search technique employs a length-normalization procedure and
uses a coverage penalty, which encourages generation of an output sentence that
is most likely to cover all the words in the source sentence. On the WMT'14
English-to-French and English-to-German benchmarks, GNMT achieves competitive
results to state-of-the-art. Using a human side-by-side evaluation on a set of
isolated simple sentences, it reduces translation errors by an average of 60%
compared to Google's phrase-based production system.


title:
On the early-time excess emission in hydrogen-poor superluminous
  supernovae

abstract:
  We present the light curves of the hydrogen-poor superluminous supernovae
(SLSNe-I) PTF12dam and iPTF13dcc, discovered by the (intermediate) Palomar
Transient Factory. Both show excess emission at early times and a slowly
declining light curve at late times. The early bump in PTF12dam is very similar
in duration (~10 days) and brightness relative to the main peak (2-3 mag
fainter) compared to those observed in other SLSNe-I. In contrast, the
long-duration (>30 days) early excess emission in iPTF13dcc, whose brightness
competes with that of the main peak, appears to be of a different nature. We
construct bolometric light curves for both targets, and fit a variety of
light-curve models to both the early bump and main peak in an attempt to
understand the nature of these explosions. Even though the slope of the
late-time light-curve decline in both SLSNe is suggestively close to that
expected from the radioactive decay of $^{56}$Ni and $^{56}$Co, the amount of
nickel required to power the full light curves is too large considering the
estimated ejecta mass. The magnetar model including an increasing escape
fraction provides a reasonable description of the PTF12dam observations.
However, neither the basic nor the double-peaked magnetar model is capable of
reproducing the iPTF13dcc light curve. A model combining a shock breakout in an
extended envelope with late-time magnetar energy injection provides a
reasonable fit to the iPTF13dcc observations. Finally, we find that the light
curves of both PTF12dam and iPTF13dcc can be adequately fit with the
circumstellar medium (CSM) interaction model.


title:
Efficiently parallelized modeling of tightly focused, large bandwidth
  laser pulses

abstract:
  The Stratton-Chu integral representation of electromagnetic fields is used to
study the spatio-temporal properties of large bandwidth laser pulses focused by
high numerical aperture mirrors. We review the formal aspects of the derivation
of diffraction integrals from the Stratton-Chu representation and discuss the
use of the Hadamard finite part in the derivation of the physical optics
approximation. By analyzing the formulation we show that, for the specific case
of a parabolic mirror, the integrands involved in the description of the
reflected field near the focal spot do not possess the strong oscillations
characteristic of diffraction integrals. Consequently, the integrals can be
evaluated with simple and efficient quadrature methods rather than with
specialized, more costly approaches. We report on the development of an
efficiently parallelized algorithm that evaluates the Stratton-Chu diffraction
integrals for incident fields of arbitrary temporal and spatial dependence.
This method has the advantage that its input is the unfocused field coming from
the laser chain, which is experimentally known with high accuracy. We use our
method to show that the reflection of a linearly polarized Gaussian beam of
femtosecond duration off a high numerical aperture parabolic mirror induces
ellipticity in the dominant field components and generates strong longitudinal
components. We also estimate that future high-power laser facilities may reach
intensities of $10^{24}\,\text{W/cm}^2$.