title:
Two-dimensional double-quantum spectroscopy: peak shapes as a sensitive
  probe of carrier interactions in quantum wells

abstract:
  We identify carrier scattering at densities below which it has previously
been observed in semiconductor quantum wells. These effects are evident in the
peakshapes of 2D double-quantum spectra, which change as a function of
excitation density. At high excitation densities ($\geq 10^{9}$
carriers/,cm$^{-2}$) we observe untilted peaks similar to those reported in
previous experiments. At low excitation densities (<$10^{8}$ carriers
cm$^{-2}$) we observe narrower, tilted peaks. Using a simple simulation, we
show that tilted peak-shapes are expected in double-quantum spectra when
inhomogeneous broadening is much larger than homogeneous broadening, and that
fast pure-decoherence of the double-quantum coherence can obscure this peak
tilt. These results show that carrier interactions are important at lower
densities than previously expected, and that the `natural' double-quantum
peakshapes are hidden by carrier interactions at the excitation densities
typically used. Furthermore, these results demonstrate that analysis of 2D
peak-shapes in double-quantum spectroscopy provides an incisive tool for
identifying interactions at low excitation density.


title: On the real rank of monomials

abstract:
  In this paper we study the real rank of monomials and we give an upper bound
for the real rank of all monomials. We show that the real and the complex ranks
of a monomial coincide if and only if the least exponent is equal to one.


title: Was there a negative vacuum energy in your past?

abstract:
  A model for gravitational collapse where the event horizon is a quantum
critical phase transition is extended to provide an explanation for the origin
of the observable universe, where the expanding universe that we observe today
was proceeded by a flat universe with a negative cosmological constant. In
principal this allows one derive all the features of our universe from a single
parameter: the magnitude of the pre-big bang negative vacuum energy density. In
this paper a simple model for the big bang is introduced which allows us to
relate the present day energy density and temperature fluctuations of the CMB,
to the present day density of dark matter. This model for the big bang also
makes a dramatic prediction: dark matter mostly consists of compact objects
with a masses on the order of 10^4 solar masses. Remarkably this is consistent
with numerical simulations for how primordial fluctuations in the density of
dark give rise to the observed inhomogeneous distribution of matter in our
universe. Our model for the big bang also allows for the production of some
compact objects with masses greater than 10^4 solar masses, which is consistent
with numerical simulations of structure formation which require massive
primordial comapact objects as the seeds for galaxies in order to explain
galactic morphologies.


title:
Using the Crab Nebula as a high precision calibrator for Cosmic
  Microwave Background polarimeters

abstract:
  The polarization of the Cosmic Microwave Background (CMB) provides a plethora
of information about the early universe. Most notably, gravitational waves from
the Inflationary epoch (the leading explanation of the origin of the universe)
create a unique CMB polarization $B$-mode signal. An unambiguous detection of
the inflationary $B$-mode signal would be a window into the physics of the
universe as it was $10^{-36}$ seconds after the Big Bang, at energy scales many
orders of magnitude larger than what the LHC can produce. However, there are
several instrumental and astrophysical sources that can obfuscate the
inflationary $B$-mode signal. One of the most difficult parameters to calibrate
for CMB telescopes is the absolute orientation of the antenna's polarization
sensitive axis. A miscalibration of the polarization orientation rotates the
much brighter $E$-mode signal, producing a false $B$-mode signal. The current
best uncertainty on polarization orientation in the CMB community is
$0.5^\circ$, set from extrapolating IRAM measurements of the Crab Nebula
supernova remnant at 90 GHz to 150 GHz, where the CMB signals peak. This
accuracy is not sufficient to convincingly detect $B$-modes predicted by
currently allowable models of Inflation. We suggest to precisely measure the
Crab Nebula's polarization, which can be calibrated absolutely to $0.1^\circ$
from measurements of the polarized emission of Mars, and use these data to
calibrate current and upcoming CMB experiments. In addition to inflationary
$B$-modes, more precise calibration will allow us to better constrain the sum
of the neutrino masses and set limits on exotic physics such as parity
violation through cosmic polarization rotation.


title: The value of Side Information in Secondary Spectrum Markets

abstract:
  In a secondary spectrum market primaries set prices for their unused channels
to the secondaries. The payoff of a primary depends on the availability of
unused channels of its competitors. We consider a model were a primary can
acquire its competitor's channel state information (C-CSI) at a cost. We
formulate a game between two primaries where each primary decides whether to
acquire C-CSI or not and then selects its price based on that. We first
characterize the Nash Equilibrium (NE) of this game for a symmetric model where
the C-CSI is perfect. We show that the payoff of a primary is independent of
the C-CSI acquisition cost. We then generalize our analysis to allow for
imperfect estimation and cases where the two primaries have different C-CSI
costs or different channel availabilities. Our results show interestingly that
the payoff of a primary increases when there is estimation error. We also show
that surprisingly, the expected payoff of a primary may decrease when the C-CSI
acquisition cost decreases when primaries have different availabilities.


title:
Exceptional damage-tolerance of a medium-entropy alloy CrCoNi at
  cryogenic temperatures

abstract:
  High-entropy alloys are an intriguing new class of metallic materials that
derive their properties from being multi-element systems that can crystallize
as a single phase, despite containing high concentrations of five or more
elements with different crystal structures. Here we examine an equiatomic
medium-entropy alloy containing only three elements, CrCoNi, as a single-phase
face-centered cubic (fcc) solid solution, which displays strength-toughness
properties that exceed those of all high-entropy alloys and most multi-phase
alloys. At room temperature the alloy shows tensile strengths of almost 1 GPa,
failure strains of ~70%, and KJIc fracture-toughness values above 200 MPa.m1/2;
at cryogenic temperatures strength, ductility and toughness of the CrCoNi alloy
improve to strength levels above 1.3 GPa, failure strains up to 90% and KJIc
values of 275 MPa.m1/2. Such properties appear to result from continuous steady
strain hardening, which acts to suppress plastic instability, resulting from
pronounced dislocation activity and deformation-induced nano-twinning.


title: Hanf Number for Scott Sentences of Computable Structures

abstract:
  The Hanf number for a set $S$ of sentences in $L_{\omega_1,\omega}$ (or some
other logic) is the least infinite cardinal $\kappa$ such that for all
$\varphi\in S$, if $\varphi$ has models in all infinite cardinalities less than
$\kappa$, then it has models of all infinite cardinalities. S-D. Friedman asked
what is the Hanf number for Scott sentences of computable structures. We show
that the value is $\beth_{\omega_1^{CK}}$. The same argument proves that
$\beth_{\omega_1^{CK}}$ is the Hanf number for Scott sentences of
hyperarithmetical structures.


title: The idempotent generated subsemigroup of the Kauffman monoid

abstract:
  We characterise the elements of the (maximum) idempotent generated
subsemigroup of the Kauffman monoid in terms of combinatorial data associated
to certain normal forms. We also calculate the smallest size of a generating
set and idempotent generating set.


title: When Isolated Horizons met Near Horizon Geometries

abstract:
  There are two mathematical relativity frameworks generalizing the black hole
theory: the theory of isolated horizons (IH) and the theory of near horizon
geometries (NHG). We outline here and discuss the derivation of the NHG from
the theory of IH by composing spacetimes from IH. The simplest but still quite
general class of solutions to Einstein's equations of this type defines
spacetimes foliated by Killing horizons emanating from extremal horizons. That
derivation, clearly being a link between the two frameworks, seems to be
unknown to the NHG researchers and is hardly acknowledged in reviews on the IH.
This lecture was a contribution to the Mathematical Structures session of the
2nd LeCosPA International Symposium "Everything about Gravity" celebrating the
centenary of Einstein's General Relativity on December 14-18, 2015 in Taipei.


title: Generalized conformal derivations of Lie conformal algebras

abstract:
  Let $R$ be a Lie conformal algebra. The purpose of this paper is to
investigate the conformal derivation algebra $CDer(R)$, the conformal
quasiderivation algebra $QDer(R)$ and the generalized conformal derivation
algebra $GDer(R)$. The generalized conformal derivation algebra is a natural
generalization of the conformal derivation algebra. Obviously, we have the
following tower $CDer(R)\subseteq QDer(R)\subseteq GDer(R)\subseteq gc(R)$,
where $gc(R)$ is the general Lie conformal algebra. Furthermore, we mainly
research the connection of these generalized conformal derivations. Finally,
the conformal $(\alpha,\beta,\gamma)$-derivations of Lie conformal algebras are
studied. Moreover, we obtain some connections between several specific
generalized conformal derivations and the conformal
$(\alpha,\beta,\gamma)$-derivations. In addition, all conformal
$(\alpha,\beta,\gamma)$-derivations of finite simple Lie conformal algebras are
characterized.


title:
Variable selection via penalized credible regions with Dirichlet-Laplace
  global-local shrinkage priors

abstract:
  The method of Bayesian variable selection via penalized credible regions
separates model fitting and variable selection. The idea is to search for the
sparsest solution within the joint posterior credible regions. Although the
approach was successful, it depended on the use of conjugate normal priors.
More recently, improvements in the use of global-local shrinkage priors have
been made for high-dimensional Bayesian variable selection. In this paper, we
incorporate global-local priors into the credible region selection framework.
The Dirichlet-Laplace (DL) prior is adapted to linear regression. Posterior
consistency for the normal and DL priors are shown, along with variable
selection consistency. We further introduce a new method to tune
hyperparameters in prior distributions for linear regression. We propose to
choose the hyperparameters to minimize a discrepancy between the induced
distribution on R-square and a prespecified target distribution. Prior
elicitation on R-square is more natural, particularly when there are a large
number of predictor variables in which elicitation on that scale is not
feasible. For a normal prior, these hyperparameters are available in closed
form to minimize the Kullback-Leibler divergence between the distributions.


title:
Energy Efficient Scheduling and Groupping for Machine-TYpe
  Communications over Cellular Networks

abstract:
  In this paper, energy-efficient scheduling for grouped machine-type devices
deployed in cellular networks is investigated. We introduce a scheduling-based
cooperation incentive scheme which enables machine nodes to organize themselves
locally, create machine groups, and communicate through group representatives
to the base station. This scheme benefits from a novel scheduler design which
takes into account the cooperation level of each node, reimburses the extra
energy consumptions of group representatives, and maximizes the network
lifetime. As reusing cellular uplink resources for communications inside the
groups degrades the Quality of Service (QoS) of the primary users, analytical
results are provided which present a tradeoff between maximum allowable number
of simultaneously active machine groups in a given cell and QoS of the primary
users. Furthermore, we extend our derived solutions for the existing cellular
networks, propose a cooperation-incentive LTE scheduler, and present our
simulation results in the context of LTE. The simulation results show that the
proposed solutions significantly prolong the network lifetime. Also, it is
shown that under certain circumstances, reusing uplink resource by machine
devices can degrade the outage performance of the primary users significantly,
and hence, coexistence management of machine devices and cellular users is of
paramount importance for next generations of cellular networks in order to
enable group-based machine-type communications while guaranteeing QoS for the
primary users.


title:
Extreme values of the stationary distribution of random walks on
  directed graphs

abstract:
  We examine the stationary distribution of random walks on directed graphs. In
particular, we focus on the {\em principal ratio}, which is the ratio of
maximum to minimum values of vertices in the stationary distribution. We give
an upper bound for this ratio over all strongly connected graphs on $n$
vertices. We characterize all graphs achieving the upper bound and we give
explicit constructions for these extremal graphs. Additionally, we show that
under certain conditions, the principal ratio is tightly bounded. We also
provide counterexamples to show the principal ratio cannot be tightly bounded
under weaker conditions.


title:
Operators $L^1 (\mathbb R_+ )\to X$ and the norm continuity problem for
  semigroups

abstract:
  We present a new method for constructing $C_0$-semigroups for which
properties of the resolvent of the generator and continuity properties of the
semigroup in the operator-norm topology are controlled simultaneously. It
allows us to show that a) there exists a $C_0$-semigroup which is continuous in
the operator-norm topology for no $t \in [0,1]$ such that the resolvent of its
generator has a logarithmic decay at infinity along vertical lines; b) there
exists a $C_0$-semigroup which is continuous in the operator-norm topology for
no $t \in \mathbb R_+$ such that the resolvent of its generator has a decay
along vertical lines arbitrarily close to a logarithmic one. These examples
rule out any possibility of characterizing norm-continuity of semigroups on
arbitrary Banach spaces in terms of resolvent-norm decay on vertical lines.


title:
Single-Solution Hypervolume Maximization and its use for Improving
  Generalization of Neural Networks

abstract:
  This paper introduces the hypervolume maximization with a single solution as
an alternative to the mean loss minimization. The relationship between the two
problems is proved through bounds on the cost function when an optimal solution
to one of the problems is evaluated on the other, with a hyperparameter to
control the similarity between the two problems. This same hyperparameter
allows higher weight to be placed on samples with higher loss when computing
the hypervolume's gradient, whose normalized version can range from the mean
loss to the max loss. An experiment on MNIST with a neural network is used to
validate the theory developed, showing that the hypervolume maximization can
behave similarly to the mean loss minimization and can also provide better
performance, resulting on a 20% reduction of the classification error on the
test set.


title:
Anisotropy in broad component of H$\alpha$ line in the magnetospheric
  device RT-1

abstract:
  Temperature anisotropy in broad component of H$\alpha$ line was found in the
ring trap 1 (RT-1) device by Doppler spectroscopy. Since hot hydrogen neutrals
emitting a broad component are mainly produced by charge exchange between
neutrals and protons, the anisotropy in the broad component is the evidence of
proton temperature anisotropy generated by betatron acceleration.


title: Entanglement renormalization and wavelets

abstract:
  We establish a precise connection between discrete wavelet transforms (WTs)
and entanglement renormalization (ER), a real-space renormalization group
transformation for quantum systems on the lattice, in the context of free
particle systems. Specifically, we employ Daubechies wavelets to build
approximations to the ground state of the critical Ising model, then
demonstrate that these states correspond to instances of the multi-scale
entanglement renormalization ansatz (MERA), producing the first known analytic
MERA for critical systems.


title: On extensions of local Dirichlet forms

abstract:
  Let $\ce$ be a Dirichlet form on $L_2(X\,;\mu)$ where $(X,\mu)$ is locally
compact $\sigma$-compact measure space. Assume $\ce$ is inner regular, i.e.\
regular in restriction to functions of compact support, and local in the sense
that
  $\ce(\varphi,\psi)=0$ for all $\varphi, \psi\in D(\ce)$ with
$\varphi\,\psi=0$. We construct two Dirichlet forms $\ce_m$ and $\ce_M$ such
that $\ce_m\leq \ce\leq \ce_M$. These forms are potentially the smallest and
largest such Dirichlet forms. In particular $\ce_m\supseteq \ce_M$,
$(\ce_M)_m=\ce_m$ and $(\ce_m)_M=\ce_M$. We analyze the family of local, inner
regular, Dirichlet forms $\cf$ which extend $\ce$ and satisfy $\ce_m\leq
\cf\leq \ce_M$. We prove that the latter bounds are valid if and only if
$\cf_M=\ce_M$, or $\cf_m=\ce_m$, or $D(\ce_M)$ is an order ideal of $D(\cf)$.
Alternatively the $\cf$ are characterized by $D(\ce_M)\cap L_\infty(X)$ being
an algebraic ideal of $D(\cf)\cap L_\infty(X)$. As an application we show that
if $\ce$ and $\cf$ are strongly local then the Ariyoshi--Hino set-theoretic
distance is the same for each of the forms $\ce$, $\ce_M$ and $\cf$. If in
addition $\ce_m$ is strongly local then it also defines the same distance.
Finally we characterize the uniqueness condition $\ce_M=\ce_m$ by capacity
estimates.


title: Learning Discriminative Features via Label Consistent Neural Network

abstract:
  Deep Convolutional Neural Networks (CNN) enforces supervised information only
at the output layer, and hidden layers are trained by back propagating the
prediction error from the output layer without explicit supervision. We propose
a supervised feature learning approach, Label Consistent Neural Network, which
enforces direct supervision in late hidden layers. We associate each neuron in
a hidden layer with a particular class label and encourage it to be activated
for input signals from the same class. More specifically, we introduce a label
consistency regularization called "discriminative representation error" loss
for late hidden layers and combine it with classification error loss to build
our overall objective function. This label consistency constraint alleviates
the common problem of gradient vanishing and tends to faster convergence; it
also makes the features derived from late hidden layers discriminative enough
for classification even using a simple $k$-NN classifier, since input signals
from the same class will have very similar representations. Experimental
results demonstrate that our approach achieves state-of-the-art performances on
several public benchmarks for action and object category recognition.


title: From Extraction of Nucleon Resonances to LQCD

abstract:
  The intrinsic difficulties in extracting the hadron resonances from reaction
data are illustrated by using several exactly soluble $\pi\pi$ scattering
models. The finite-volume Hamiltonian method is applied to predict spectra
using two meson-exchange Hamiltonians of $\pi N$ reactions. Within a
three-channel model with $\pi N$, $\pi\Delta$ and $\sigma N$ channels, we show
the advantage of the finite-volume Hamiltonian method over the approach using
the L\"uscher formula to test Lattice QCD calculations aimed at predicting
nucleon resonances. We discuss the necessary steps for using the ANL-Osaka
eight-channel Hamiltonian to predict the spectra for testing the LQCD
calculations for determining the excited nucleon states up to invariant mass
$W= 2 $ GeV.


title: Results and Analysis of SyGuS-Comp'15

abstract:
  Syntax-Guided Synthesis (SyGuS) is the computational problem of finding an
implementation f that meets both a semantic constraint given by a logical
formula $\varphi$ in a background theory T, and a syntactic constraint given by
a grammar G, which specifies the allowed set of candidate implementations. Such
a synthesis problem can be formally defined in SyGuS-IF, a language that is
built on top of SMT-LIB.
  The Syntax-Guided Synthesis Competition (SyGuS-comp) is an effort to
facilitate, bring together and accelerate research and development of efficient
solvers for SyGuS by providing a platform for evaluating different synthesis
techniques on a comprehensive set of benchmarks. In this year's competition we
added two specialized tracks: a track for conditional linear arithmetic, where
the grammar need not be specified and is implicitly assumed to be that of the
LIA logic of SMT-LIB, and a track for invariant synthesis problems, with
special constructs conforming to the structure of an invariant synthesis
problem. This paper presents and analyzes the results of SyGuS-comp'15.


title: The Second Reactive Synthesis Competition (SYNTCOMP 2015)

abstract:
  We report on the design and results of the second reactive synthesis
competition (SYNTCOMP 2015). We describe our extended benchmark library, with 6
completely new sets of benchmarks, and additional challenging instances for 4
of the benchmark sets that were already used in SYNTCOMP 2014. To enhance the
analysis of experimental results, we introduce an extension of our benchmark
format with meta-information, including a difficulty rating and a reference
size for solutions. Tools are evaluated on a set of 250 benchmarks, selected to
provide a good coverage of benchmarks from all classes and difficulties. We
report on changes of the evaluation scheme and the experimental setup. Finally,
we describe the entrants into SYNTCOMP 2015, as well as the results of our
experimental evaluation. In our analysis, we emphasize progress over the tools
that participated last year.


title: Synthesizing a Lego Forklift Controller in GR(1): A Case Study

abstract:
  Reactive synthesis is an automated procedure to obtain a
correct-by-construction reactive system from a given specification. GR(1) is a
well-known fragment of linear temporal logic (LTL) where synthesis is possible
using a polynomial symbolic algorithm. We conducted a case study to learn about
the challenges that software engineers may face when using GR(1) synthesis for
the development of a reactive robotic system. In the case study we developed
two variants of a forklift controller, deployed on a Lego robot. The case study
employs LTL specification patterns as an extension of the GR(1) specification
language, an examination of two specification variants for execution
scheduling, traceability from the synthesized controller to constraints in the
specification, and generated counter strategies to support understanding
reasons for unrealizability. We present the specifications we developed, our
observations, and challenges faced during the case study.


title: A multi-paradigm language for reactive synthesis

abstract:
  This paper proposes a language for describing reactive synthesis problems
that integrates imperative and declarative elements. The semantics is defined
in terms of two-player turn-based infinite games with full information.
Currently, synthesis tools accept linear temporal logic (LTL) as input, but
this description is less structured and does not facilitate the expression of
sequential constraints. This motivates the use of a structured programming
language to specify synthesis problems. Transition systems and guarded commands
serve as imperative constructs, expressed in a syntax based on that of the
modeling language Promela. The syntax allows defining which player controls
data and control flow, and separating a program into assumptions and
guarantees. These notions are necessary for input to game solvers. The
integration of imperative and declarative paradigms allows using the paradigm
that is most appropriate for expressing each requirement. The declarative part
is expressed in the LTL fragment of generalized reactivity(1), which admits
efficient synthesis algorithms, extended with past LTL. The implementation
translates Promela to input for the Slugs synthesizer and is written in Python.
The AMBA AHB bus case study is revisited and synthesized efficiently,
identifying the need to reorder binary decision diagrams during strategy
construction, in order to prevent the exponential blowup observed in previous
work.


title: Compositional Algorithms for Succinct Safety Games

abstract:
  We study the synthesis of circuits for succinct safety specifications given
in the AIG format. We show how AIG safety specifications can be decomposed
automatically into sub specifications. Then we propose symbolic compositional
algorithms to solve the synthesis problem compositionally starting for the
sub-specifications. We have evaluated the compositional algorithms on a set of
benchmarks including those proposed for the first synthesis competition
organised in 2014 by the Synthesis Workshop affiliated to the CAV conference.
We show that a large number of benchmarks can be decomposed automatically and
solved more efficiently with the compositional algorithms that we propose in
this paper.


title: Specification Format for Reactive Synthesis Problems

abstract:
  Automatic synthesis from a given specification automatically constructs
correct implementation. This frees the user from the mundane implementation
work, but still requires the specification. But is specifying easier than
implementing? In this paper, we propose a user-friendly format to ease the
specification work, in particularly, that of specifying partial
implementations. Also, we provide scripts to convert specifications in the new
format into the SYNTCOMP format, thus benefiting from state of the art
synthesizers.


title:
The complexity of approximations for epistemic synthesis (extended
  abstract)

abstract:
  Epistemic protocol specifications allow programs, for settings in which
multiple agents act with incomplete information, to be described in terms of
how actions are related to what the agents know. They are a variant of the
knowledge-based programs of Fagin et al [Distributed Computing, 1997],
motivated by the complexity of synthesizing implementations in that framework.
The paper proposes an approach to the synthesis of implementations of epistemic
protocol specifications, that reduces the problem of finding an implementation
to a sequence of model checking problems in approximations of the ultimate
system being synthesized. A number of ways to construct such approximations is
considered, and these are studied for the complexity of the associated model
checking problems. The outcome of the study is the identification of the best
approximations with the property of being PTIME implementable.


title: SU(3) quantum critical model emerging from a spin-1 topological phase

abstract:
  Different from the spin-1 Haldane gapped phase, we propose a novel SO(3)
spin-1 matrix product state (MPS), whose parent Hamiltonian includes three-site
spin interactions. From the entanglement spectrum of a single block with $l$
sites, an enlarged SU(3) symmetry is identified in the edge states, which are
conjugate to each other for the $l=even$ block but identical for the $l=odd$
block. By blocking this novel state, the blocked MPS explicitly displays the
SU(3) symmetry with two distinct structures. Under a symmetric bulk bipartition
with a sufficient large block length $% l=even$, the entanglement Hamiltonian
(EH) of the reduced system characterizes a spontaneous dimerized phase with
two-fold degeneracy. However, for the block length $l=odd$, the corresponding
EH represents an SU(3) quantum critical point with delocalized edge
quasiparticles, and the critical field theory is described by the SU(3) level-1
Wess-Zumino-Witten conformal field theory.


title: GECKA3D: A 3D Game Engine for Commonsense Knowledge Acquisition

abstract:
  Commonsense knowledge representation and reasoning is key for tasks such as
artificial intelligence and natural language understanding. Since commonsense
consists of information that humans take for granted, gathering it is an
extremely difficult task. In this paper, we introduce a novel 3D game engine
for commonsense knowledge acquisition (GECKA3D) which aims to collect
commonsense from game designers through the development of serious games.
GECKA3D integrates the potential of serious games and games with a purpose.
This provides a platform for the acquisition of re-usable and multi-purpose
knowledge, and also enables the development of games that can provide
entertainment value and teach players something meaningful about the actual
world they live in.


title:
Unconventional Spin Hall Effect and Axial Current Generation in a Dirac
  Semimetal

abstract:
  We investigate electrical transport in a three-dimensional massless Dirac
fermion model that describes a Dirac semimetal state realized in topological
materials. We derive a set of interdependent diffusion equations with eight
local degrees of freedom, including the electric charge density and the spin
density, that respond to an external electric field. By solving the diffusion
equations for a system with a boundary, we demonstrate that a spin Hall effect
with spin accumulation occurs even though the conventional spin current
operator is zero. The Noether current associated with chiral symmetry, known as
the axial current, is also discussed. We demonstrate that the axial current
flows near the boundary and that it is perpendicular to the electric current.


title:
Continuum-atomistic simulation of picosecond laser heating of copper
  with electron heat capacity from ab initio calculation

abstract:
  On the basis of ab initio quantum mechanics (QM) calculation, the obtained
electron heat capacity is implemented into energy equation of electron
subsystem in two temperature model (TTM). Upon laser irradiation on the copper
film, energy transfer from the electron subsystem to the lattice subsystem is
modeled by including the electron-phonon coupling factor in molecular dynamics
(MD) and TTM coupled simulation. The results show temperature and thermal
melting difference between the QM-MD-TTM integrated simulation and pure MD-TTM
coupled simulation. The successful construction of the QM-MD-TTM integrated
simulation provide a general way that is accessible to other metals in laser
heating.


title:
Searching for $\tau \rightarrow \mu \gamma$ lepton-flavor-violating
  decay at super charm-tau factory

abstract:
  We investigate the possibility of searching the lepton-flavor-violating (LFV)
$\tau\rightarrow \mu\gamma$ rare decay at the Super Charm-Tau Factory (CTF). By
comparing the kinematic distributions of the LFV signal and the standard model
(SM) background, we develop an optimized event selection criteria which can
significantly reduce the background events. It is concluded that new $2 \sigma$
upper limit of about $1.9 \times 10^{-9}$ on $Br(\tau \rightarrow \mu \gamma)$
can be obtained at the CTF, which is beyond the capability of Super-B factory
in searching $\tau$ lepton rare decay. Within the framework of the scalar
leptoquark model, a joint constraint on $\lambda_1 \lambda_2$ and $M_{LQ}$ can
be derived from the upper bound on $Br(\tau \rightarrow \mu \gamma)$. With
$1000~ fb^{-1}$ data expected at the CTF, we get $\lambda_1\lambda_2 < 7.2
\times 10^{-2}~(M_{LQ} = 800~ {\rm GeV})$ and $M_{LQ} > 900~{\rm
GeV}~(\lambda_1 \lambda_2 = 9 \times 10^{-2})$ at $95\%$ confidence level
(C.L.).


title: High-Dimensional Regularized Discriminant Analysis

abstract:
  Regularized discriminant analysis (RDA), proposed by Friedman (1989), is a
widely popular classifier that lacks interpretability and is impractical for
high-dimensional data sets. Here, we present an interpretable and
computationally efficient classifier called high-dimensional RDA (HDRDA),
designed for the small-sample, high-dimensional setting. For HDRDA, we show
that each training observation, regardless of class, contributes to the class
covariance matrix, resulting in an interpretable estimator that borrows from
the pooled sample covariance matrix. Moreover, we show that HDRDA is equivalent
to a classifier in a reduced-feature space with dimension approximately equal
to the training sample size. As a result, the matrix operations employed by
HDRDA are computationally linear in the number of features, making the
classifier well-suited for high-dimensional classification in practice. We
demonstrate that HDRDA is often superior to several sparse and regularized
classifiers in terms of classification accuracy with three artificial and six
real high-dimensional data sets. Also, timing comparisons between our HDRDA
implementation in the sparsediscrim R package and the standard RDA formulation
in the klaR R package demonstrate that as the number of features increases, the
computational runtime of HDRDA is drastically smaller than that of RDA.


title:
Rapidity and centrality dependence of particle production for identified
  hadrons in Cu+Cu collisions at $\sqrt{s_{NN}} = 200$ GeV

abstract:
  The BRAHMS collaboration has measured transverse momentum spectra of pions,
kaons, protons and antiprotons at rapidities 0 and 3 for Cu+Cu collisions at
$\sqrt{s_{NN}} = 200$ GeV. As the collisions become more central the collective
radial flow increases while the temperature of kinetic freeze-out decreases.
The temperature is lower and the radial flow weaker at forward rapidity. Pion
and kaon yields with transverse momenta between 1.5 and 2.5 GeV/c are
suppressed for central collisions relative to scaled $p+p$ collisions. This
suppression, which increases as the collisions become more central is
consistent with jet quenching models and is also present with comparable
magnitude at forward rapidity. At such rapidities initial state effects may
also be present and persistence of the meson suppression to high rapidity may
reflect a combination of jet quenching and nuclear shadowing. The ratio of
protons to mesons increases as the collisions become more central and is
largest at forward rapidities.


title:
Smooth subgrid fields underpin rigorous closure in spatial
  discretisation of reaction-advection-diffusion PDEs

abstract:
  Finite difference/element/volume methods of discretising PDEs impose a
subgrid scale interpolation on the dynamics. In contrast, the holistic
discretisation approach developed herein constructs a natural subgrid scale
field adapted to the whole system out-of-equilibrium dynamics. Consequently,
the macroscale discretisation is fully informed by the underlying microscale
dynamics. We establish a new proof that in principle there exists an exact
closure of the dynamics of a general class of reaction-advection-diffusion
PDEs, and show how our approach constructs new systematic approximations to the
in-principle closure starting from a simple, piecewise-linear, continuous
approximation. Under inter-element coupling conditions that guarantee
continuity of several field properties, the holistic discretisation possesses
desirable properties such as a natural cubic spline first-order approximation
to the field, and the self-adjointness of the diffusion operator under
periodic, Dirichlet and Neumann macroscale boundary conditions. As a concrete
example, we demonstrate the holistic discretisation procedure on the well-known
Burgers' PDE, and compare the theoretical and numerical stability of the
resulting discretisation to other approximations. The approach developed here
promises to be able to systematically construct automatically good, macroscale
discretisations to a wide range of PDEs, including wave PDEs.


title:
Advances in Thermal Modeling of Selective Laser Sintering of Metal
  Powders

abstract:
  Selective laser sintering (SLS) of single component metal powders is a rapid
prototyping technology in which a high-energy laser beam scans, melts, shrinks
and consolidates metal powders with single component. For better understanding
physical mechanisms during laser sintering of single-component metal particles,
a temperature transforming model with the consideration of shrinkage and
convective flows is introduced to analyze the thermal/fluid behaviors in
selective laser sintering of single powder layer. The model is also applied to
investigate the sintering of powders on top of existing sintered layers under
single- multiple-line scanning manners according to the practical manufacturing
processes.


title:
Heat and Mass Transfer during Chemical Vapor Deposition on the Particle
  Surface Subjected to Nanosecond Laser Heating

abstract:
  A thermal model of chemical vapor deposition of titanium nitride (TiN) on the
spherical particle surface under irradiation by a nanosecond laser pulse is
presented in this paper. Heat and mass transfer on a single spherical metal
powder particle surface subjected to temporal Gaussian heat flux is
investigated analytically. The chemical reaction on the particle surface and
the mass transfer in the gas phase are also considered. The surface
temperature, thermal penetration depth, and deposited film thickness under
different laser fluence, pulse width, initial particle temperature, and
particle radius are investigated. The effect of total pressure in the reaction
chamber on deposition rate is studied as well. The particle-level model
presented in this paper is an important step toward development of multiscale
model of LCVI.


title:
Geometric foundations for scaling-rotation statistics on symmetric
  positive definite matrices: minimal smooth scaling-rotation curves in low
  dimensions

abstract:
  We investigate a geometric computational framework, called the
"scaling-rotation framework", on ${\rm Sym}^+(p)$, the set of $p \times p$
symmetric positive-definite (SPD) matrices. The purpose of our study is to lay
geometric foundations for statistical analysis of SPD matrices, in situations
in which eigenstructure is of fundamental importance, for example
diffusion-tensor imaging (DTI). Eigen-decomposition, upon which the
scaling-rotation framework is based, determines both a stratification of ${\rm
Sym}^+(p)$, defined by eigenvalue multiplicities, and fibers of the
"eigen-composition" map $SO(p)\times{\rm Diag}^+(p)\to{\rm Sym}^+(p)$. This
leads to the notion of scaling-rotation distance [Jung et al. (2015)], a
measure of the minimal amount of scaling and rotation needed to transform an
SPD matrix, $X,$ into another, $Y,$ by a smooth curve in ${\rm Sym}^+(p)$. Our
main goal in this paper is the systematic characterization and analysis of
minimal smooth scaling-rotation (MSSR) curves, images in ${\rm Sym}^+(p)$ of
minimal-length geodesics connecting two fibers in the "upstairs" space
$SO(p)\times{\rm Diag}^+(p)$. The length of such a geodesic connecting the
fibers over $X$ and $Y$ is what we define to be the scaling-rotation distance
from $X$ to $Y.$ For the important low-dimensional case $p = 3$ (the home of
DTI), we find new explicit formulas for MSSR curves and for the
scaling-rotation distance, and identify ${\cal M}(X,Y)$ in all "nontrivial"
cases. The quaternionic representation of $SO(3)$ is used in these
computations. We also provide closed-form expressions for scaling-rotation
distance and MSSR curves for the case $p = 2$.


title: General Boundary Quantum Field Theory in Anti de Sitter Spacetimes

abstract:
  We mainly study real Klein-Gordon theory on Anti de Sitter spacetimes, and
apply the General Boundary Formulation (GBF) of Quantum Theory in order to
compute a radial S-matrix. We consider first the classical theory, giving a
complete list of Klein-Gordon solutions and the actions of the isometries of
AdS on them. We study two symplectic structures on spaces of such solutions,
and show that they are invariant under all isometries' actions. We also
calculate the flat limits of the involved quantities, and find that it
reproduces the respective counterparts of the theory on Minkowski spacetime. We
proceed applying Holomorphic Quantization, whose amplitudes are determined by
an inner product which is induced by the symplectic structure together with a
complex structure on the space of classical solutions. We construct this
complex structure such that the inner product becomes positive-definite, and
its induced amplitudes are invariant under time-translations and spatial
rotations. Further, our complex structure makes these radial amplitudes agree
with the amplitudes of states on equal-time hypersurfaces, and also reproduce
the amplitudes of the theory on Minkowski spacetime in the flat limit. (There
is also a more detailed summary at the beginning of the document.)


title: On Curvature Tensors of Hermitian Manifolds

abstract:
  In this article, we examine the behavior of the Riemannian and Hermitian
curvature tensors of a Hermitian metric, when one of the curvature tensors
obeys all the symmetry conditions of the curvature tensor of a K\"ahler metric.
We will call such metrics G-K\"ahler-like or K\"ahler-like, for lack of better
terminologies. Such metrics are always balanced when the manifold is compact,
so in a way they are more special than balanced metrics, which drew a lot of
attention in the study of non-K\"ahler Calabi-Yau manifolds. In particular we
derive various formulas on the difference between the Riemannian and Hermitian
curvature tensors in terms of the torsion of the Hermitian connection. We
believe that these formulas could lead to further applications in the study of
Hermitian geometry with curvature assumptions.


title:
Dipolar quantization and the infinite circumference limit of
  two-dimensional conformal field theories

abstract:
  Elaborating on our previous presentation, where the term {\it dipolar
quantization} was introduced, we argue here that adopting
$L_0-(L_1+L_{-1})/2+{\bar L}_0-({\bar L}_1+{\bar L}_{-1})/2$ as the Hamiltonian
instead of $L_0+{\bar L}_0$ yields an infinite circumference limit in
two-dimensional conformal field theory. The new Hamiltonian leads to dipolar
quantization instead of radial quantization. As a result, the new theory
exhibits a continuous and strongly degenerated spectrum in addition to the
Virasoro algebra with a continuous index. Its Hilbert space exhibits a
different inner product than that obtained in the original theory. The
idiosyncrasy of this particular Hamiltonian is its relation to the so-called
sine-square deformation, which is found in the study of a certain class of
quantum statistical systems. The appearance of the infinite circumference
explains why the vacuum states of sine-square deformed systems are coincident
with those of the respective closed-boundary systems.


title:
Network biomarkers of schizophrenia by graph theoretical investigations
  of Brain Functional Networks

abstract:
  Brain Functional Networks (BFNs), graph theoretical models of brain activity
data, provide a systems perspective of complex functional connectivity within
the brain. Neurological disorders are known to have basis in abnormal
functional activities, that could be captured in terms of network markers.
Schizophrenia is a pathological condition characterized with altered brain
functional state. We created weighted and binary BFN models of schizophrenia
patients as well as healthy subjects starting from fMRI data in an effort to
search for network biomarkers of the disease. We investigated 45 topological
features of BFNs and their higher order combinations (2 to 8). We find that
network features embodying modularity, betweenness, assortativity and edge
density emerge as key markers of schizophrenia. Also, features derived from
weighted BFNs were observed to be more effective in disease classification as
compared to those from binary BFNs. These topological markers may provide
insights into mechanisms of functional activity underlying disease phenotype
and could further be used for designing algorithms for clinical diagnosis of
schizophrenia as well as its early detection.


title: Prediction models for network-linked data

abstract:
  Prediction algorithms typically assume the training data are independent
samples, but in many modern applications samples come from individuals
connected by a network. For example, in adolescent health studies of
risk-taking behaviors, information on the subjects' social network is often
available and plays an important role through network cohesion, the empirically
observed phenomenon of friends behaving similarly. Taking cohesion into account
in prediction models should allow us to improve their performance. Here we
propose a network-based penalty on individual node effects to encourage
similarity between predictions for linked nodes, and show that incorporating it
into prediction leads to improvement over traditional models both theoretically
and empirically when network cohesion is present. The penalty can be used with
many loss-based prediction methods, such as regression, generalized linear
models, and Cox's proportional hazard model. Applications to predicting levels
of recreational activity and marijuana usage among teenagers from the AddHealth
study based on both demographic covariates and friendship networks are
discussed in detail and show that our approach to taking friendships into
account can significantly improve predictions of behavior while providing
interpretable estimates of covariate effects.


title:
Multiple solutions for a Kirchhoff-type equation with general
  nonlinearity

abstract:
  This paper is devoted to the study of the following autonomous Kirchhoff-type
equation $$-M\left(\int_{\mathbb{R}^N}|\nabla{u}|^2\right)\Delta{u}=
f(u),~~~~u\in H^1(\mathbb{R}^N),$$ where $M$ is a continuous non-degenerate
function and $N\geq2$. Under suitable additional conditions on $M$ and general
Berestycki-Lions type assumptions on the nonlinearity $f$, we establish several
existence results of multiple solutions by variational methods, which are also
naturally interpreted from a non-variational point of view.


title:
Robust tunability of magnetorestance in Half-Heusler RPtBi (R = Gd, Dy,
  Tm, and Lu) compounds

abstract:
  We present the magnetic field dependencies of transport properties for
$R$PtBi ($R$ = Gd, Dy, Tm, and Lu) half-Heusler compounds. Temperature and
field dependent resistivity measurements of high quality $R$PtBi single
crystals reveal an unusually large, non-saturating magnetoresistance (MR) up to
300 K under a moderate magnetic field of $H$ = 140 kOe. At 300 K, the large MR
effect decreases as the rare-earth is traversed from Gd to Lu and the magnetic
field dependence of MR shows a deviation from the conventional $H^{2}$
behavior. The Hall coefficient ($R_{H}$) for $R$ = Gd indicates a sign change
around 120 K, whereas $R_{H}$ curves for $R$ = Dy, Tm, and Lu remain positive
for all measured temperatures. At 300 K, the Hall resistivity reveals a
deviation from the linear field dependence for all compounds. Thermoelectric
power measurements on this family show strong temperature and magnetic field
dependencies which are consistent with resistivity measurements. A highly
enhanced thermoelectric power under applied magnetic field is observed as high
as $\sim$100 $\mu$V/K at 140 kOe. Analysis of the transport data in this series
reveals that the rare-earth-based Half-Husler compounds provide opportunities
to tune MR effect through lanthanide contraction and to elucidate the mechanism
of non-trivial MR.


title: The UBV Color Evolution of Classical Novae. II. Color-Magnitude Diagram

abstract:
  We have examined the outburst tracks of 40 novae in the color-magnitude
diagram (intrinsic B-V color versus absolute V magnitude). After reaching the
optical maximum, each nova generally evolves toward blue from the upper-right
to the lower-left and then turns back toward the right. The 40 tracks are
categorized into one of six templates: very fast nova V1500 Cyg; fast novae
V1668 Cyg, V1974 Cyg, and LV Vul; moderately fast nova FH Ser; and very slow
nova PU Vul. These templates are located from the left (blue) to the right
(red) in this order, depending on the envelope mass and nova speed class. A
bluer nova has a less massive envelope and faster nova speed class. In novae
with multiple peaks, the track of the first decay is more red than that of the
second (or third) decay, because a large part of the envelope mass had already
been ejected during the first peak. Thus, our newly obtained tracks in the
color-magnitude diagram provide useful information to understand the physics of
classical novae. We also found that the absolute magnitude at the beginning of
the nebular phase is almost similar among various novae. We are able to
determine the absolute magnitude (or distance modulus) by fitting the track of
a target nova to the same classification of a nova with a known distance. This
method for determining nova distance has been applied to some recurrent novae
and their distances have been recalculated.


title: Principal stratification analysis using principal scores

abstract:
  Practitioners are interested in not only the average causal effect of the
treatment on the outcome but also the underlying causal mechanism in the
presence of an intermediate variable between the treatment and outcome.
However, in many cases we cannot randomize the intermediate variable, resulting
in sample selection problems even in randomized experiments. Therefore, we view
randomized experiments with intermediate variables as semi-observational
studies. In parallel with the analysis of observational studies, we provide a
theoretical foundation for conducting objective causal inference with an
intermediate variable under the principal stratification framework, with
principal strata defined as the joint potential values of the intermediate
variable. Our strategy constructs weighted samples based on principal scores,
defined as the conditional probabilities of the latent principal strata given
covariates, without access to any outcome data. This principal stratification
analysis yields robust causal inference without relying on any model
assumptions on the outcome distributions. We also propose approaches to
conducting sensitivity analysis for violations of the ignorability and
monotonicity assumptions, the very crucial but untestable identification
assumptions in our theory. When the assumptions required by the classical
instrumental variable analysis cannot be justified by background knowledge or
cannot be made because of scientific questions of interest, our strategy serves
as a useful alternative tool to deal with intermediate variables. We illustrate
our methodologies by using two real data examples, and find scientifically
meaningful conclusions.


title: Discriminative Sparse Neighbor Approximation for Imbalanced Learning

abstract:
  Data imbalance is common in many vision tasks where one or more classes are
rare. Without addressing this issue conventional methods tend to be biased
toward the majority class with poor predictive accuracy for the minority class.
These methods further deteriorate on small, imbalanced data that has a large
degree of class overlap. In this study, we propose a novel discriminative
sparse neighbor approximation (DSNA) method to ameliorate the effect of
class-imbalance during prediction. Specifically, given a test sample, we first
traverse it through a cost-sensitive decision forest to collect a good subset
of training examples in its local neighborhood. Then we generate from this
subset several class-discriminating but overlapping clusters and model each as
an affine subspace. From these subspaces, the proposed DSNA iteratively seeks
an optimal approximation of the test sample and outputs an unbiased prediction.
We show that our method not only effectively mitigates the imbalance issue, but
also allows the prediction to extrapolate to unseen data. The latter capability
is crucial for achieving accurate prediction on small dataset with limited
samples. The proposed imbalanced learning method can be applied to both
classification and regression tasks at a wide range of imbalance levels. It
significantly outperforms the state-of-the-art methods that do not possess an
imbalance handling mechanism, and is found to perform comparably or even better
than recent deep learning methods by using hand-crafted features only.


title: k-variates++: more pluses in the k-means++

abstract:
  k-means++ seeding has become a de facto standard for hard clustering
algorithms. In this paper, our first contribution is a two-way generalisation
of this seeding, k-variates++, that includes the sampling of general densities
rather than just a discrete set of Dirac densities anchored at the point
locations, and a generalisation of the well known Arthur-Vassilvitskii (AV)
approximation guarantee, in the form of a bias+variance approximation bound of
the global optimum. This approximation exhibits a reduced dependency on the
"noise" component with respect to the optimal potential --- actually
approaching the statistical lower bound. We show that k-variates++ reduces to
efficient (biased seeding) clustering algorithms tailored to specific
frameworks; these include distributed, streaming and on-line clustering, with
direct approximation results for these algorithms. Finally, we present a novel
application of k-variates++ to differential privacy. For either the specific
frameworks considered here, or for the differential privacy setting, there is
little to no prior results on the direct application of k-means++ and its
approximation bounds --- state of the art contenders appear to be significantly
more complex and / or display less favorable (approximation) properties. We
stress that our algorithms can still be run in cases where there is \textit{no}
closed form solution for the population minimizer. We demonstrate the
applicability of our analysis via experimental evaluation on several domains
and settings, displaying competitive performances vs state of the art.


title:
Chandra Detection of X-ray Emission from Ultra-compact Dwarf Galaxies
  and Extended Star Clusters

abstract:
  We have conducted a systematic study of X-ray emission from ultra-compact
dwarf (UCD) galaxies and extended star clusters (ESCs), based on archival {\sl
Chandra} observations. Among a sample of 511 UCDs and ESCs complied from the
literature, 17 X-ray counterparts with 0.5-8 keV luminosities above
$\sim$$5\times10^{36} {\rm~erg~s^{-1}}$ are identified, which are distributed
in eight early-type host galaxies. To facilitate comparison, we also identify
X-ray counterparts of 360 globular clusters (GCs) distributed in four of the
eight galaxies. The X-ray properties of the UCDs and ESCs are found to be
broadly similar to those of the GCs. The incidence rate of X-ray-detected UCDs
and ESCs, $(3.3\pm0.8)$\%, while lower than that of the X-ray-detected GCs
[($7.0\pm0.4)$\%], is substantially higher than expected from the field
populations of external galaxies. A stacking analysis of the individually
undetected UCDs/ESCs further reveals significant X-ray signals, which
corresponds to an equivalent 0.5-8 keV luminosity of $\sim$$4\times10^{35}
{\rm~erg~s^{-1}}$ per source. Taken together, these provide strong evidence
that the X-ray emission from UCDs and ESCs is dominated by low-mass X-ray
binaries having formed from stellar dynamical interactions, consistent with the
stellar populations in these dense systems being predominantly old. For the
most massive UCDs, there remains the possibility that a putative central
massive black hole gives rise to the observed X-ray emission.


title:
Gauss-Galerkin quadrature rules for quadratic and cubic spline spaces
  and their application to isogeometric analysis

abstract:
  We introduce Gaussian quadrature rules for spline spaces that are frequently
used in Galerkin discretizations to build mass and stiffness matrices. By
definition, these spaces are of even degrees. The optimal quadrature rules we
recently derived [5] act on spaces of the smallest odd degrees and, therefore,
are still slightly sub-optimal. In this work, we derive optimal rules directly
for even-degree spaces and therefore further improve our recent result. We use
optimal quadrature rules for spaces over two elements as elementary building
blocks and use recursively the homotopy continuation concept described in [6]
to derive optimal rules for arbitrary admissible number of elements. We
demonstrate the proposed methodology on relevant examples, where we derive
optimal rules for various even-degree spline spaces. We also discuss
convergence of our rules to their asymptotic counterparts, these are the
analogues of the midpoint rule of Hughes et al. [16], that are exact and
optimal for infinite domains.


title:
Instability of standing waves for a system of nonlinear Schr\"odinger
  equations in a degenerate case

abstract:
  We study a system of nonlinear Schr\"odinger equations with cubic
interactions in one space dimension. The orbital stability and instability of
semitrivial standing wave solutions are studied for both non-degenerate and
degenerate cases.


title: Locally rewritable codes for resistive memories

abstract:
  We propose locally rewritable codes (LWC) for resistive memories inspired by
locally repairable codes (LRC) for distributed storage systems. Small values of
repair locality of LRC enable fast repair of a single failed node since the
lost data in the failed node can be recovered by accessing only a small
fraction of other nodes. By using rewriting locality, LWC can improve endurance
limit and power consumption which are major challenges for resistive memories.
We point out the duality between LRC and LWC, which indicates that existing
construction methods of LRC can be applied to construct LWC.


title:
The Sower's way. Quantifying the Narrowing Net-Energy Pathways to a
  Global Energy Transition

abstract:
  Planning the appropriate renewable energy installation rate should balance
two partially contradictory objectives: substituting fossil fuels fast enough
to stave-off the worst consequences of climate change while maintaining a
sufficient net energy flow to support the world's economy. The upfront energy
invested in constructing a renewable energy infrastructure subtracts from the
net energy available for societal energy needs, a fact typically neglected in
energy projections. Modeling feasible energy transition pathways to provide
different net energy levels we find that they are critically dependent on the
fossil fuel emissions cap and phase-out profile and on the characteristic
energy return on energy invested of the renewable energy technologies. The
easiest pathway requires installation of renewable energy plants to accelerate
from 0.12TWp/year in 2013 to peak between 6.6 and 10.4 TWp/year, for an early
or a late fossil-fuel phase-out respectively in order for emissions to stay
within the recommended CO2 budget.


title:
Direct Observation of Localized Radial Oxygen Migration in Functioning
  Tantalum Oxide Memristors

abstract:
  Oxygen migration in tantalum oxide, a promising next-generation storage
material, is studied using in-operando x-ray absorption spectromicroscopy and
is used to microphysically describe accelerated evolution of conduction channel
and device failure. The resulting ring-like patterns of oxygen concentration
are modeled using thermophoretic forces and Fick diffusion, establishing the
critical role of temperature-activated oxygen migration that has been under
question lately.


title: Citations to articles citing Benford's law: a Benford analysis

abstract:
  The occurrence of first significant digits of numbers in large data is often
governed by a logarithmically decreasing distribution called Benford's law
(BL), reported first by S. Newcomb (SN) and many decades later independently by
F. Benford (FB). Due to its counter-intuitiveness the law was ignored for
decades as a mere curious observation. However, an indication of its remarkable
resurgence is the huge swell in the number of citations received by the papers
of SN/FB. The law has come a long way, from obscurity to now being a regular
subject of books, peer reviewed papers, patents, blogs and news. Here, we use
Google Scholar (GS) to collect the data on the number of citations received by
the articles citing the original paper of SN/FB and then investigate whether
the leading digits of this citations data are distributed according to the law
they discovered. We find that the citations data of literature on BL is in
remarkable agreement with the predictions of the law.


title: denoiseR: A Package for Low Rank Matrix Estimation

abstract:
  We introduce denoiseR, an R package that provides a unified implementation of
several state-of-the-art proposals for regularized low rank matrix estimation,
along with automatic selection of the regularization parameters. We also extend
these methods to allow for missing values. The regularization schemes discussed
in this paper are built around singular-value shrinkage and bootstrap-based
stability arguments. We illustrate how to use out package by applying it to
several real and simulated datasets, and highlight strengths and weaknesses of
the different implemented methods.


title: Kac polynomials for canonical algebras

abstract:
  We prove that the number of geometrically indecomposable representations of
fixed dimension vector d of a canonical algebra C defined over a finite field
Fq is given by a polynomial in q (depending on C and d). We prove a similar
result for squid algebras (and for any almost concealed canonical algebra).
Finally we express the volume of the moduli stacks of representations of these
algebras of a fixed dimension vector in terms of the corresponding Kac
polynomials.


title:
Spatial Concept Acquisition for a Mobile Robot that Integrates
  Self-Localization and Unsupervised Word Discovery from Spoken Sentences

abstract:
  In this paper, we propose a novel unsupervised learning method for the
lexical acquisition of words related to places visited by robots, from human
continuous speech signals. We address the problem of learning novel words by a
robot that has no prior knowledge of these words except for a primitive
acoustic model. Further, we propose a method that allows a robot to effectively
use the learned words and their meanings for self-localization tasks. The
proposed method is nonparametric Bayesian spatial concept acquisition method
(SpCoA) that integrates the generative model for self-localization and the
unsupervised word segmentation in uttered sentences via latent variables
related to the spatial concept. We implemented the proposed method SpCoA on
SIGVerse, which is a simulation environment, and TurtleBot2, which is a mobile
robot in a real environment. Further, we conducted experiments for evaluating
the performance of SpCoA. The experimental results showed that SpCoA enabled
the robot to acquire the names of places from speech sentences. They also
revealed that the robot could effectively utilize the acquired spatial concepts
and reduce the uncertainty in self-localization.


title: q-Vertex Operator from 5D Nekrasov Function

abstract:
  The five dimensional AGT correspondence implies the connection between the
q-deformed Virasoro block and the 5d Nekrasov partition function. In this
paper, we determine a q-deformation of the four-point block in the Coulomb gas
representation from the 5d Nekrasov function, and obtain an expression of the
q-deformed vertex operator. If we use only one kind of the q-vertex operators,
one of the insertion points of them must be modified in order to hold the 2d/5d
correspondence.


title: A simple proof of the detectability lemma and spectral gap amplification

abstract:
  The detectability lemma is a useful tool for probing the structure of gapped
ground states of frustration-free Hamiltonians of lattice spin models. The
lemma provides an estimate on the error incurred by approximating the ground
space projector with a product of local projectors. We provide a new, simpler
proof for the detectability lemma, which applies to an arbitrary ordering of
the local projectors, and show that it is tight up to a constant factor. As an
application we show how the lemma can be combined with a strong converse by Gao
to obtain local spectral gap amplification: we show that by coarse-graining a
local frustration-free Hamiltonian with a spectral gap $\gamma>0$ to a length
scale $O(\gamma^{-1/2})$, one gets an Hamiltonian with an $\Omega(1)$ spectral
gap.


title:
A Fractional Micro-Macro Model for Crowds of Pedestrians based on
  Fractional Mean Field Games

abstract:
  Modeling of crowds of pedestrians has been considered in this paper from
different aspects. Based on fractional microscopic model that may be much more
close to reality, a fractional macroscopic model has been proposed using
conservation law of mass. Then in order to characterize the competitive and
cooperative interactions among pedestrians, fractional mean field games are
utilized in the modeling problem when the number of pedestrians goes to
infinity and fractional dynamic model composed of fractional backward and
fractional forward equations are constructed in macro scale. Fractional
micro-macro model for crowds of pedestrians are obtained in the end. Simulation
results are also included to illustrate the proposed fractional microscopic
model and fractional macroscopic model respectively.


title:
A symmetric 2-tensor canonically associated to Q-curvature and its
  applications

abstract:
  In this article, we define a symmetric 2-tensor canonically associated to
Q-curvature called J-tensor on any Riemannian manifold with dimension at least
three. The relation between J-tensor and Q-curvature is precisely like Ricci
tensor and scalar curvature. Thus it can be interpreted as a higher-order
analogue of Ricci tensor. This tensor can also be used to understand
Chang-Gursky-Yang's theorem on 4-dimensional Q-singular metrics. Moreover, we
show an Almost-Schur Lemma holds for Q-curvature, which gives an estimate of
Q-curvature on closed manifolds.


title:
Maximum leave-one-out likelihood estimation for location parameter of
  unbounded densities

abstract:
  Maximum likelihood estimation of a location parameter fails when the density
have unbounded mode. An alternative approach is considered by leaving out a
data point to avoid the unbounded density in the full likelihood. This
modification give rise to the leave-one-out likelihood. We propose an ECM
algorithm which maximises the leave-one-out likelihood. It was shown that the
estimator which maximises the leave-one-out likelihood is consistent and
super-efficient. However, other asymptotic properties such as the optimal rate
of convergence and asymptotic distribution is still under question. We use
simulations to investigate these asymptotic properties of the location
estimator using our proposed algorithm.


title:
On the Z_2-graded codimensions of the Grassmann algebra over a finite
  field

abstract:
  Let E be the infinite dimensional Grassmann algebra over a finite field F of
characteristic not 2. In this paper we deal with the homogeneous Z_2-gradings
of E. In particular, we compute an exact value for the Z_2-graded homogeneous
codimensions of E, and a lower and an upper bound for the Z_2-graded
(non-homogeneous) codimensions of E for each of its Z_2-homogeneous grading.


title:
Maximal $m$-distance sets containing the representation of the Hamming
  graph $H(n,m)$

abstract:
  A set $X$ in the Euclidean space $\mathbb{R}^d$ is called an $m$-distance set
if the set of Euclidean distances between two distinct points in $X$ has size
$m$. An $m$-distance set $X$ in $\mathbb{R}^d$ is said to be maximal if there
does not exist a vector $x$ in $\mathbb{R}^d$ such that the union of $X$ and
$\{x\}$ still has only $m$ distances. Bannai--Sato--Shigezumi (2012)
investigated the maximal $m$-distance sets which contain the Euclidean
representation of the Johnson graph $J(n,m)$. In this paper, we consider the
same problem for the Hamming graph $H(n,m)$. The Euclidean representation of
$H(n,m)$ is an $m$-distance set in $\mathbb{R}^{m(n-1)}$. We prove that the
maximum $n$ is $m^2 + m - 1$ such that the representation of $H(n,m)$ is not
maximal as an $m$-distance set. Moreover we classify the largest $m$-distance
sets which contain the representation of $H(n,m)$ for $m\leq 4$ and any $n$. We
also classify the maximal $2$-distance sets in $\mathbb{R}^{2n-1}$ which
contain the representation of $H(n,2)$ for any $n$.


title: Inflation and the Measurement Problem

abstract:
  We propose a solution to the quantum measurement problem in Inflation. Our
model treats Fourier modes of cosmological perturbations as analogous to
particles in a weakly-interacting Bose gas. We generalize the idea of a
macroscopic wavefunction to cosmological fields, and construct a
self-interaction Hamiltonian that focuses that wavefunction. By appropriately
setting the coupling between modes, we obtain the standard adiabatic,
scale-invariant power spectrum. Because of Central Limit Theorem (CLT), we
recover a Gaussian Random Field, consistent with observations.


title: Deformations of Superconformal Theories

abstract:
  We classify possible supersymmetry-preserving relevant, marginal, and
irrelevant deformations of unitary superconformal theories in $d \geq 3$
dimensions. Our method only relies on symmetries and unitarity. Hence, the
results are model independent and do not require a Lagrangian description. Two
unifying themes emerge: first, many theories admit deformations that reside in
multiplets together with conserved currents. Such deformations can lead to
modifications of the supersymmetry algebra by central and non-central charges.
Second, many theories with a sufficient amount of supersymmetry do not admit
relevant or marginal deformations, and some admit neither. The classification
is complicated by the fact that short superconformal multiplets display a rich
variety of sporadic phenomena, including supersymmetric deformations that
reside in the middle of a multiplet. We illustrate our results with examples in
diverse dimensions. In particular, we explain how the classification of
irrelevant supersymmetric deformations can be used to derive known and new
constraints on moduli-space effective actions.


title: On the Accuracy of Interference Models in Wireless Communications

abstract:
  We develop a new framework for measuring and comparing the accuracy of any
wireless interference models used in the analysis and design of wireless
networks. Our approach is based on a new index that assesses the ability of the
interference model to correctly predict harmful interference events, i.e., link
outages. We use this new index to quantify the accuracy of various interference
models used in the literature, under various scenarios such as Rayleigh fading
wireless channels, directional antennas, and blockage (impenetrable obstacles)
in the network. Our analysis reveals that in highly directional antenna
settings with obstructions, even simple interference models (e.g., the
classical protocol model) are accurate, while with omnidirectional antennas,
more sophisticated and complex interference models (e.g., the classical
physical model) are necessary. Our new approach makes it possible to adopt the
appropriate interference model of adequate accuracy and simplicity in different
settings.


title:
The Matryoshka Disk: Keck/NIRC2 Discovery of a Solar System-Scale,
  Radially Segregated Residual Protoplanetary Disk Around HD 141569A

abstract:
  Using Keck/NIRC2 $L^\prime$ (3.78 $\mu m$) data, we report the direct imaging
discovery of a scattered light-resolved, solar system-scale residual
protoplanetary disk around the young A-type star HD 141569A, interior to and
concentric with the two ring-like structures at wider separations. The disk is
resolved down to $\sim$ 0\farcs{}25 and appears as an arc-like rim with
attached hook-like features. It is located at an angular separation
intermediate between that of warm CO gas identified from spatially-resolved
mid-infrared spectroscopy and diffuse dust emission recently discovered with
the \textit{Hubble Space Telescope}. The inner disk has a radius of $\sim$ 39
AU, a position angle consistent with north-up, an inclination of $i$ $\sim$
56$^{o}$, and has a center offset from the star. Forward-modeling of the disk
favors a thick torus-like emission sharply truncated at separations beyond the
torus' photocenter and heavily depleted at smaller separations. In particular,
the best-fit density power law for the dust suggests that the inner disk dust
and gas (as probed by CO) are radially segregated, a feature consistent with
the dust trapping mechanism inferred from observations of "canonical"
transitional disks. However, the inner disk component may instead be explained
by radiation pressure-induced migration in optically-thin conditions, in
contrast to the two stellar companion/planet-influenced ring-like structures at
wider separations. HD 141569A's circumstellar environment --- with three
nested, gapped, concentric dust populations --- is an excellent laboratory for
understanding the relationship between planet formation and the evolution of
both dust grains and disk architecture.


title:
Magneto-excitons in large area CVD grown monolayer MoS$_{2}$ and
  MoSe$_{2}$ on sapphire

abstract:
  Magneto transmission spectroscopy was employed to study the valley Zeeman
effect in large-area monolayer MoS$_{2}$ and MoSe$_{2}$. The extracted values
of the valley g-factors for both A- and B-exciton were found be similar with
$g_v \simeq -4.5$. The samples are expected to be strained due to the CVD
growth on sapphire at high temperature ($700^\circ$C). However, the estimated
strain, which is maximum at low temperature, is only $\simeq 0.2\%$.
Theoretical considerations suggest that the strain is too small to
significantly influence the electronic properties. This is confirmed by the
measured value of valley g-factor, and the measured temperature dependence of
the band gap, which are almost identical for CVD and mechanically exfoliated
MoS$_2$.


title:
Oscillatory power spectrum and strongly $k$-dependent $r$ in hybrid
  inflation

abstract:
  For the original hybrid inflation model, we calculate the power spectrum of
curvature perturbations generated during the waterfall, taking into account the
contribution of entropic modes. We study the regime where the potential is very
flat, and in which inflation continues for more than about 60 e-folds. Results
show oscillations in the scalar power spectrum, qualitatively similar to that
of a single field axion monodromy potential; however no feature is displayed in
the tensor power spectrum. Directions to develop a template for this power
spectrum are also discussed.


title: The leading term of the Yang-Mills free energy

abstract:
  This article gives an explicit formula for the leading term of the free
energy of three-dimensional $U(N)$ lattice gauge theory for any $N$, as the
lattice spacing tends to zero. The proof is based on a novel technique that
avoids phase cell renormalization. The technique also yields a similar formula
for the four-dimensional theory, but only in the weak coupling~limit.


title:
Impact of $BaTiO_3$ nanoparticles on pretransitional effects in liquid
  crystalline dodecylcyanobiphenyl

abstract:
  The pretransitional behavior of dodecylcyanobiphenyl (12CB)
(isotropic-smectic-A-solid mesomorphism) with $d = 50$ nm $BaTiO_3$
nanoparticles (NPs) linked the cubic phase was monitored via temperature
studies of dielectric constant. Tests were carried out in the isotropic, liquid
crystal mesomorphic and solid phases. For each phase transition the same value
of the critical exponent $\alpha=0.5$ was obtained, including nanocolloids. All
phase transitions show the weakly discontinuous nature. The temperature metric
of the discontinuity dT notably decreases when adding nanoparticles. The
addition of nanoparticles first decreases the dielectric constant by approx.
$50%$ in comparison with pure 12CB, but already for a concentration $x = 0.4%%
NPs an increase over $50%$ takes place. It is notable that for the latter
concentration unique hallmarks of the pretransitional effect emerge also for
the solid-mesophase transition. All thease indicate the important impact of
nanoparticles on multimolecular mesoscale fluctuations.


title: Smooth surface interpolation using patches with rational offsets

abstract:
  We present a new method for the interpolation of given data points and
associated normals with surface parametric patches with rational normal fields.
We give some arguments why a dual approach is the most convenient for these
surfaces, which are traditionally called Pythagorean normal vector (PN)
surfaces. Our construction is based on the isotropic model of the dual space to
which the original data are pushed. Then the bicubic Coons patches are
constructed in the isotropic space and then pulled back to the standard three
dimensional space. As a result we obtain the patch construction which is
completely local and produces surfaces with the global G1~continuity.


title:
Non-ideal torque control of wind turbine systems: Impacts on annual
  energy production

abstract:
  We discuss non-ideal torque control in wind turbine systems (WTS). Most
high-level controllers generate a reference torque which is then send to the
underlying electrical drive system (generator+inverter) of the WTS to steer the
turbine/generator to its optimal operation point (depending on the wind speed).
The energy production heavily depends on the mechanical power (i.e. the product
of rotational speed and generator torque). However, since torque sensors in the
MW range are not available or extremely expensive, the torque controllers are
implemented as feedforward controllers and, therefore, are inherently sensitive
to parameter variations/uncertainties. Based on real wind data and a dynamical
WTS model, we discuss causes and impacts of non-ideal (feedforward) torque
control on the energy production and the gross earnings.


title:
Maintenance of Automated Test Suites in Industry: An Empirical study on
  Visual GUI Testing

abstract:
  Context: Verification and validation (V&V) activities make up 20 to 50
percent of the total development costs of a software system in practice. Test
automation is proposed to lower these V&V costs but available research only
provides limited empirical data from industrial practice about the maintenance
costs of automated tests and what factors affect these costs. In particular,
these costs and factors are unknown for automated GUI-based testing.
  Objective: This paper addresses this lack of knowledge through analysis of
the costs and factors associated with the maintenance of automated GUI-based
tests in industrial practice.
  Method: An empirical study at two companies, Siemens and Saab, is reported
where interviews about, and empirical work with, Visual GUI Testing is
performed to acquire data about the technique's maintenance costs and
feasibility.
  Results: 13 factors are observed that affect maintenance, e.g. tester
knowledge/experience and test case complexity. Further, statistical analysis
shows that developing new test scripts is costlier than maintenance but also
that frequent maintenance is less costly than infrequent, big bang maintenance.
In addition a cost model, based on previous work, is presented that estimates
the time to positive return on investment (ROI) of test automation compared to
manual testing.
  Conclusions: It is concluded that test automation can lower overall software
development costs of a project whilst also having positive effects on software
quality. However, maintenance costs can still be considerable and the less time
a company currently spends on manual testing, the more time is required before
positive, economic, ROI is reached after automation.


title: Determinantal variety and normal embedding

abstract:
  The space of matrices of positive determinant GL^+_n inherits an extrinsic
metric space structure from R^{n^2}. On the other hand, taking the infimum of
the lengths of all paths connecting two points in GL^+_n gives an intrinsic
metric. We prove bilipschitz equivalence for intrinsic and extrinsic metrics on
GL^+_n, exploiting the conical structure of the stratification of the space of
n by n matrices by rank.


title: Image and Information

abstract:
  A well-known old adage says that {\em "A picture is worth a thousand words!"}
(attributed to the Chinese philosopher Confucius ca 500 years BC). But more
precisely, what do we mean by information in images? And how can it be
retrieved effectively by machines? We briefly highlight these puzzling
questions in this column. But first of all, let us start by defining more
precisely what is meant by an "Image."


title: The First MAXI/SSC Catalog of X-ray Sources in 0.7--7.0~keV

abstract:
  We present the first source catalog of the Solid-state Slit Camera (SSC) of
the Monitor of All-sky X-ray Image (MAXI) mission on the International Space
Station, using the 45-month data from 2010 August to 2014 April in 0.7--7.0~keV
bands. Sources are searched for in two energy bands, 0.7--1.85~keV (soft) and
1.85--7.0~keV (hard), the limiting sensitivity of 3 and 4~mCrab are achieved
and 140 and 138 sources are detected in the soft and hard energy bands,
respectively. Combining the two energy bands, 170 sources are listed in the
MAXI/SSC catalog. All but 2 sources are identified with 22 galaxies including
AGNs, 29 cluster of galaxies, 21 supernova remnants, 75 X-ray binaries, 8
stars, 5 isolated pulsars, and 9 non-categorized objects. Comparing the
soft-band fluxes at the brightest end in our catalog with the ROSAT survey,
which was performed about 20 years ago, 10\% of the cataloged sources are found
to have changed the flux since the ROSAT era.


title:
Random pure states: quantifying bipartite entanglement beyond the linear
  statistics

abstract:
  We analyze the properties of entangled random pure states of a quantum system
partitioned into two smaller subsystems of dimensions $N$ and $M$. Framing the
problem in terms of random matrices with a fixed-trace constraint, we
establish, for arbitrary $N \leq M$, a general relation between the $n$-point
densities and the cross-moments of the eigenvalues of the reduced density
matrix, i.e. the so-called Schmidt eigenvalues, and the analogous functionals
of the eigenvalues of the Wishart-Laguerre ensemble of the random matrix
theory. This allows us to derive explicit expressions for two-level densities,
and also an exact expression for the variance of von Neumann entropy at finite
$N,M$. Then we focus on the moments $\mathbb{E}\{K^a\}$ of the Schmidt number
$K$, the reciprocal of the purity. This is a random variable supported on
$[1,N]$, which quantifies the number of degrees of freedom effectively
contributing to the entanglement. We derive a wealth of analytical results for
$\mathbb{E}\{K^a\}$ for $N = 2$ and $N=3$ and arbitrary $M$, and also for
square $N = M$ systems by spotting for the latter a connection with the
probability $P(x_{min}^{GUE} \geq \sqrt{2N}\xi)$ that the smallest eigenvalue
$x_{min}^{GUE}$ of a $N\times N$ matrix belonging to the Gaussian Unitary
Ensemble is larger than $\sqrt{2N}\xi$. As a byproduct, we present an exact
asymptotic expansion for $P(x_{min}^{GUE} \geq \sqrt{2N}\xi)$ for finite $N$ as
$\xi \to \infty$. Our results are corroborated by numerical simulations
whenever possible, with excellent agreement.

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


title: Di-Higgs Decay of Stoponium at Future Photon-Photon Collider

abstract:
  We study the detectability of the stoponium in the di-Higgs decay mode at the
photon-photon collider option of the International $e^+e^-$ Linear Collider
(ILC), whose center-of-mass energy is planned to reach $\sim 1$ TeV. We find
that $5\sigma$ detection of the di-Higgs decay mode is possible with the
integrated electron-beam luminosity of $1 {\rm ab}^{-1}$ if the signal cross
section, $\sigma(\gamma \gamma \rightarrow \sigma_{\tilde{t}_1} \rightarrow
hh)$, of ${\cal O}(0.1)$ fb is realized for the stoponium mass smaller than
$\sim$ 800 GeV at 1 TeV ILC. Such a value of the cross section can be realized
in the minimal supersymmetric standard model (MSSM) with relatively large
trilinear stop-stop-Higgs coupling constant. Implication of the stoponium cross
section measurement for the MSSM stop sector is also discussed.


title:
On the Distribution of the Number of Goldbach Partitions of a Randomly
  Chosen Positive Even Integer

abstract:
  Let $\mathcal{P}=\{p_1,p_2,...\}$ be the set of all odd primes arranged in
increasing order. A Goldbach partition of the even integer $2k>4$ is a way of
writing it as a sum of two primes from $\mathcal{P}$ without regard to order.
Let $Q(2k)$ be the number of all Goldbach partitions of the number $2k$. Assume
that $2k$ is selected uniformly at random from the interval $(4,2n], n>2$, and
let $Y_n=Q(2k)$ with probability $1/(n-2)$. We prove that the random variable
$\frac{Y_n}{n/\left(\frac{1}{2}\log{n}\right)^2}$ converges weakly, as
$n\to\infty$, to a uniformly distributed random variable in the interval
$(0,1)$. The method of proof uses size-biasing and the Laplace transform
continuity theorem.


title:
Characterizing diophantine henselian valuation rings and valuation
  ideals

abstract:
  We give a characterization, in terms of the residue field, of those henselian
valuation rings and those henselian valuation ideals that are diophantine. This
characterization gives a common generalization of all the positive and negative
results on diophantine henselian valuation rings and diophantine valuation
ideals in the literature. We also treat questions of uniformity and we apply
the results to show that a given field can carry at most one diophantine
nontrivial equicharacteristic henselian valuation ring or valuation ideal.


title: Efficient formulas for efficiency correction of cumulants

abstract:
  We derive formulas which connect cumulants of particle numbers observed with
efficiency losses with the original ones based on the binomial model. These
formulas can describe the case with multiple efficiencies in a compact form.
Compared with the presently suggested ones based on factorial moments, these
formulas would drastically reduce the numerical cost for efficiency corrections
when the order of the cumulant and the number of different efficiencies are
large. The efficiency correction with realistic $p_T$-dependent efficiency
would be carried out with the aid of these formulas.


title: Quantum Zeno effect and non-Markovianity in a three-level system

abstract:
  We study the coexistence of the quantum Zeno effect and non-Markovianity for
a system decaying in a structured bosonic environment and subject to a control
field. The interaction with the environment induces decay from the excited to
the ground level, which, in turn, is coherently coupled to another meta-stable
state. The control of the strength of the coherent coupling between the stable
levels allows the engineering of both the dissipation and of the memory
effects, without modifying neither the system-reservoir interaction, nor
environmental properties. We use this framework in two different parameter
regimes corresponding to fast (bad cavity limit) and slow dissipation (good
cavity limit) in the original, un-controlled qubit system. Our results show a
non-monotonic behavior of memory effects when increasing the effectiveness of
the Zeno-like freezing. Moreover, we identify a new source of memory effects
which allows the persistence of non-Markovianity for long times while the
excited state has already been depleted.


title: Search for $XYZ$ states in $\Lambda_b$ decays at the LHCb

abstract:
  We consider $X(3872)$ and $Y(4140)$ as the vector tetraquark states of
$X_c^0\equiv c\bar c u\bar u(d\bar d)$ and $c\bar c s\bar s$, respectively. By
connecting $\Lambda_b\to X_c^0\Lambda$ to $B^-\to X_c^0 K^-$, we predict that
the branching ratios of $\Lambda_b\to \Lambda(X(3872)^0\to) J/\psi \pi^+\pi^-$
and $\Lambda_b\to \Lambda(Y(4140)\to) J/\psi \phi$ are $(5.2\pm 1.8)\times
10^{-6}$ and $(4.7\pm 2.6)\times 10^{-6}$, which are accessible to the
experiments at the LHCb, respectively. The measurements of these $\Lambda_b$
modes would be the first experimental evidences for the $XYZ$ states in
baryonic decays.


title: How Far are We from Solving Pedestrian Detection?

abstract:
  Encouraged by the recent progress in pedestrian detection, we investigate the
gap between current state-of-the-art methods and the "perfect single frame
detector". We enable our analysis by creating a human baseline for pedestrian
detection (over the Caltech dataset), and by manually clustering the recurrent
errors of a top detector. Our results characterize both localization and
background-versus-foreground errors. To address localization errors we study
the impact of training annotation noise on the detector performance, and show
that we can improve even with a small portion of sanitized training data. To
address background/foreground discrimination, we study convnets for pedestrian
detection, and discuss which factors affect their performance. Other than our
in-depth analysis, we report top performance on the Caltech dataset, and
provide a new sanitized set of training and test annotations.


title:
Spectroscopic Survey of Eclipsing Binaries with a Low Cost \'{E}chelle
  Spectrograph -- Scientific Commissioning

abstract:
  We present scientific results obtained with a recently commissioned
\'{e}chelle spectrograph on the 0.5-m Solaris-1 telescope in the South African
Astronomical Observatory. BACHES is a low-cost slit \'{e}chelle spectrograph
that has a resolution of 21,000 at 5,500 \AA. The described setup is fully
remotely operated and partly automated. Custom hardware components have been
designed to allow both spectroscopic and photometric observations. The setup is
controlled via dedicated software. The throughput of the system allows us to
obtain spectra with an average SNR of 22 at 6375 {\AA} for a 30-min exposure of
a $V=10$ mag target. The stability of the instrument is influenced mainly by
the ambient temperature changes. We have obtained radial velocity RMS values
for a bright (V = 5.9 mag) spectroscopic binary as good as 0.59 km s$^{-1}$ and
1.34 km s$^{-1}$ for a $V = 10.2$ mag eclipsing binary. Radial velocity
measurements have been combined with available photometric light curves. We
present models of six eclipsing binary systems, and for previously known
targets, we compare our results with those available in the literature. Masses
of binary components have been determined with 3% errors for some targets. We
confront our results with benchmark values based on measurements from the HARPS
and UCLES spectrographs on 4-m class telescopes and find very good agreement.
The described setup is very efficient and well suited for a spectroscopic
survey. We can now spectroscopically characterize about 300 eclipsing binary
stars per year up to 10.2 mag assuming typical weather conditions at SAAO
without a single observing trip.


title: SimProp v2r3: Monte Carlo simulation code of UHECR propagation

abstract:
  We introduce the new version of SimProp, a Monte Carlo code for simulating
the propagation of ultra-high energy cosmic rays in intergalactic space. This
version, SimProp v2r3, allows the choice of many more models for the
extragalactic background light spectrum and evolution and photodisintegration
cross sections and branching ratios than previous versions of SimProp.


title: On the apparent failure of the topological theory of phase transitions

abstract:
  The topological theory of phase transitions has its strong point in two
theorems proving that, for a wide class of physical systems, phase transitions
necessarily stem from topological changes of some submanifolds of configuration
space. It has been recently argued that the $2D$ lattice $\phi^4$-model
provides a counterexample that falsifies this theory. It is here shown that
this is not the case: the phase transition of this model stems from an
asymptotic ($N\to\infty$) change of topology of the energy level sets, in spite
of the absence of critical points of the potential in correspondence of the
transition energy.


title:
Using separable non-negative matrix factorization techniques for the
  analysis of time-resolved Raman spectra

abstract:
  The key challenge of time-resolved Raman spectroscopy is the identification
of the constituent species and the analysis of the kinetics of the underlying
reaction network. In this work we present an integral approach that allows for
determining both the component spectra and the rate constants simultaneously
from a series of vibrational spectra. It is based on an algorithm for
non-negative matrix factorization which is applied to the experimental data set
following a few pre-processing steps. As a prerequisite for physically
unambiguous solutions, each component spectrum must include one vibrational
band that does not significantly interfere with vibrational bands of other
species. The approach is applied to synthetic "experimental" spectra derived
from model systems comprising a set of species with component spectra differing
with respect to their degree of spectral interferences and signal-to-noise
ratios. In each case, the species involved are connected via monomolecular
reaction pathways. The potential and limitations of the approach for recovering
the respective rate constants and component spectra are discussed.


title: Galois Correspondence on Linear Codes over Finite Chain Rings

abstract:
  Given $\texttt{S}|\texttt{R}$ a finite Galois extension of finite chain rings
and $\mathcal{B}$ an $\texttt{S}$-linear code we define two Galois operators,
the closure operator and the interior operator. We proof that a linear code is
Galois invariant if and only if the row standard form of its generator matrix
has all entries in the fixed ring by the Galois group and show a Galois
correspondence in the class of $\texttt{S}$-linear codes. As applications some
improvements of upper and lower bounds for the rank of the restriction and
trace code are given and some applications to $\texttt{S}$-linear cyclic codes
are shown.


title: Generalized adjoint forms on algebraic varieties

abstract:
  We prove a full generalization of the Castelnuovo's free pencil trick. We
show its analogies with the Adjoint Theorem; see L. Rizzi, F. Zucconi,
Differential forms and quadrics of the canonical image, arXiv:1409.1826 and
also Theorem 1.5.1 in G. P. Pirola, F. Zucconi, Variations of the Albanese
morphisms, J. Algebraic Geom. 12 (2003), no. 3, 535-572. Moreover we find a new
formulation of the Griffiths's infinitesimal Torelli Theorem for smooth
projective hypersurfaces using meromorphic $1$-forms.


title:
Geometric compactification of moduli spaces of half-translation
  structures on surfaces

abstract:
  In this paper, we give an equivariant compactification of the space PFlat(S)
of homothety classes of half-translation structures on a compact, connected,
orientable surface S. We introduce the space PMix(S) of homothety classes of
mixed structures on S, that are CAT(0) tree-graded spaces in the sense of Drutu
and Sapir, with pieces which are R-trees and completions of surfaces endowed
with half-translation structures. Endowing Mix(S) with the equivariant Gromov
topology, and using asymptotic cone techniques, we prove that PMix(S) is an
equivariant compactification of PFlat(S), thus allowing us to understand in a
geometric way the degenerations of half-translation structures on S. We finally
compare our compactification to the one of Duchin-Leininger-Rafi, based on
geodesic currents on S, by the mean of the translation distances of the
elements of the covering group of S.


title: Revealing the spin optics of conics

abstract:
  Ellipse and hyperbola are two well-known curves in mathematics with numerous
applications in various fields, but their properties and inherent differences
in spin optics are less understood. Here, we investigate the peculiar optical
spin properties of the two curves and establish a connection between their foci
and the spin states of incident light. We show that the optical spin Hall
effect is the intrinsic optical spin property of ellipse, where photons with
different spin states can be exactly separated to each of its two foci. While a
hyperbola exhibits optical spin-selective effect, where only photons with one
particular spin state can be accumulated at its foci. These properties are then
experimentally demonstrated in near field by arranging nanoslits in conic
shape. Based on the spin properties of the curves, we design spin-based
plasmonic devices with various functionalities. Our results reveal the
intrinsic optical spin properties behind conic curves and provide a route for
designing spin-based plasmonic device.


title: Computing with quasiseparable matrices

abstract:
  The class of quasiseparable matrices is defined by a pair of bounds, called
the quasiseparable orders, on the ranks of the maximal sub-matrices entirely
located in their strictly lower and upper triangular parts. These arise
naturally in applications, as e.g. the inverse of band matrices, and are widely
used for they admit structured representations allowing to compute with them in
time linear in the dimension and quadratic with the quasiseparable order. We
show, in this paper, the connection between the notion of quasisepa-rability
and the rank profile matrix invariant, presented in [Dumas \& al. ISSAC'15].
This allows us to propose an algorithm computing the quasiseparable orders (rL,
rU) in time O(n^2 s^($\omega$--2)) where s = max(rL, rU) and $\omega$ the
exponent of matrix multiplication. We then present two new structured
representations, a binary tree of PLUQ decompositions, and the Bruhat
generator, using respectively O(ns log n/s) and O(ns) field elements instead of
O(ns^2) for the previously known generators. We present algorithms computing
these representations in time O(n^2 s^($\omega$--2)). These representations
allow a matrix-vector product in time linear in the size of their
representation. Lastly we show how to multiply two such structured matrices in
time O(n^2 s^($\omega$--2)).