title: Lectures on S-matrices and Integrability

abstract:
  In these notes we review the S-matrix theory in (1+1)-dimensional integrable
models, focusing mainly on the relativistic case. Once the main definitions and
physical properties are introduced, we discuss the factorization of scattering
processes due to integrability. We then focus on the analytic properties of the
two-particle scattering amplitude and illustrate the derivation of the
S-matrices for all the possible bound states using the so-called bootstrap
principle. General algebraic structures underlying the S-matrix theory and its
relation with the form factors axioms are briefly mentioned. Finally, we
discuss the S-matrices of sine-Gordon and SU(2), SU(3) chiral Gross-Neveu
models. This is part of a collection of lecture notes for the Young Researchers
Integrability School, organized by the GATIS network at Durham University on
6-10 July 2015.


title: Lectures on the Bethe Ansatz

abstract:
  We give a pedagogical introduction to the Bethe ansatz techniques in
integrable QFTs and spin chains. We first discuss and motivate the general
framework of asymptotic Bethe ansatz for the spectrum of integrable QFTs in
large volume, based on the exact S-matrix. Then we illustrate this method in
several concrete theories. The first case we study is the SU(2) chiral
Gross-Neveu model. We derive the Bethe equations via algebraic Bethe ansatz,
solving in the process the Heisenberg XXX spin chain. We discuss this famous
spin chain model in some detail, covering in particular the coordinate Bethe
ansatz, some properties of Bethe states, and the classical scaling limit
leading to finite-gap equations. Then we proceed to the more involved SU(3)
chiral Gross-Neveu model and derive the Bethe equations using nested algebraic
Bethe ansatz to solve the arising SU(3) spin chain. Finally we show how a
method similar to the Bethe ansatz works in a completley different setting,
namely for the 1d oscillator in quantum mechanics.
  This article is part of a collection of introductory reviews originating from
lectures given at the YRIS summer school in Durham during July 2015.


title: Introduction to the thermodynamic Bethe ansatz

abstract:
  We give a pedagogical introduction to the thermodynamic Bethe ansatz, a
method that allows us to describe the thermodynamics of integrable models whose
spectrum is found via the (asymptotic) Bethe ansatz. We set the stage by
deriving the Fermi-Dirac distribution and associated free energy of free
electrons, and then in a similar though technically more complicated fashion
treat the thermodynamics of integrable models, focusing on the one dimensional
Bose gas with delta function interaction as a clean pedagogical example,
secondly the XXX spin chain as an elementary (lattice) model with prototypical
complicating features in the form of bound states, and finally the SU(2) chiral
Gross-Neveu model as a field theory example. Throughout this discussion we
emphasize the central role of particle and hole densities, whose relations
determine the model under consideration. We then discuss tricks that allow us
to use the same methods to describe the exact spectra of integrable field
theories on a circle, in particular the chiral Gross-Neveu model. We moreover
discuss the simplification of TBA equations to Y systems, including the
transition back to integral equations given sufficient analyticity data, in
simple examples.

categories: hep-th cond-mat.str-el math-ph math.MP nlin.SI


title:
Lectures on Integrable Structures in Quantum Field Theory and Massive
  ODE/IM Correspondence

abstract:
  This review was born as notes for a lecture given at the YRIS school on
integrability in Durham, in the summer of 2015. It deals with a beautiful
method, developed in the mid-nineties by V.V. Bazhanov, S.L. Lukyanov and A.B.
Zamolodchikov and, as such, called BLZ. This method can be interpreted as a
field theory version of the quantum inverse scattering (QIS), also known as
algebraic Bethe ansatz (ABA). Starting with the case of conformal field
theories (CFT) we show how to build the field theory analogues of commuting
transfer T matrices and Baxter Q-operators of integrable lattice models. These
objects contain the complete information of the integrable structure of the
theory, viz. the integrals of motion, and can be used, as we will show, to
derive the thermodynamic Bethe ansatz (TBA) and non-linear integral (NLIE)
equations. This same method can be easily extended to the description of
integrable structures of certain particular massive deformations of CFTs;
these, in turn, can be described as quantum group reductions of the quantum
sine-Gordon model and it is an easy step to include this last theory in the
framework of BLZ approach. Finally we show an interesting and surprising
connection of the BLZ structures with classical objects emerging from the study
of classical integrable models via the inverse scattering transform method.
This connection goes under the name of ODE/IM correspondence and we will
present it for the specific case of quantum sine-Gordon model only.

categories: math-ph cond-mat.stat-mech math.MP nlin.SI


title:
Massless states and negative mass states of the coupled
  electron-positron system with completely symmetric representation of the
  particles

abstract:
  We argue that the free electron and positron can be considered as different,
independent particles, each of which is characterized by the complete set of
the Dirac plane waves. This completely symmetric representation of the
particles makes it necessary to choose another solution of the Dirac equation
for the free particle propagator as compared to that currently used in QED. The
Bethe-Salpeter equation is studied in the ladder approximation with using these
free propagators. A new branch of electron-positron bound states which
represent the massless composite bosons, have been found for the actual
coupling equal to the fine structure constant. We have obtained that: 1) the
massless boson states have the normalized complex wave functions; 2) the
average distance between the electron and positron diverges as the boson
kinetic energy goes to zero; 3) the spatial contraction of the wave function of
the transverse motion of strongly coupled electron-positron pair is
continuously occurred with increasing the boson kinetic energy. Unlike the
usual annihilation process in which nothing remains from the electron and
positron, a similar annihilation-like process in which the reaction products
are two or three gamma quanta and the massless boson, is predicted. In this
symmetric representation one could expect states, which have a certain symmetry
relative to Ps states, but have negative masses. For these states the
equal-time bound-state equation was derived neglecting the interaction
retardation and interaction through the vector potential. It turned out that
the wave functions of the negative mass boson states are not normalized. Beyond
these assumptions, the existence of these negative mass states remains unclear.


title: Pure plate bending in couple stress theories

abstract:
  In this paper, we examine the pure bending of plates within the framework of
modified couple stress theory (M-CST) and consistent couple stress theory
(C-CST). In this development, it is demonstrated that M-CST does not describe
pure bending of a plate properly. Particularly, M-CST predicts no
couple-stresses and no size effect for the pure bending of the plate into a
spherical shell. This contradicts our expectation that couple stress theory
should predict some size effect for such a deformation pattern. Therefore, this
result clearly demonstrates another inconsistency of indeterminate symmetric
modified couple stress theory (M-CST), which is based on considering the
symmetric torsion tensor as the curvature tensor. On the other hand, the fully
determinate skew-symmetric consistent couple stress theory (C-CST) predicts
results for pure plate bending that tend to agree with mechanics intuition and
experimental evidence. Particularly, C-CST predicts couple-stresses and size
effects for the pure bending of the plate into a spherical shell, which
represents an additional illustration of its consistency.


title: Schr\"odinger's cat in a realist quantum mechanics

abstract:
  There is no paradox with Schr\"odinger's cat in a realist interpretation
because in such an interpretation wave functions which represent the same
object at different times are not to be superposed.


title: On 750 GeV Diphoton Resonance in Stringy Standard-Like Models

abstract:
  The LHC diphoton excess 750 GeV is discussed in a string-inspired
standard-like model. Precisely, a singlet scalar-extended SM from a vacua of
four stacks of intersecting D6-branes giving rise to a large gauge symmetry is
considered. Besides its relevant couplings to the SM sector, the involved
scales allow for a scalar mass near to the reported diphoton excess.


title: Multifractal methodology

abstract:
  Various methods have been developed independently to study the
multifractality of measures in many different contexts. Although they all
convey the same intuitive idea of giving a "dimension" to sets where a quantity
scales similarly within a space, they are not necessarily equivalent on a more
rigorous level. This review article aims at unifying the multifractal
methodology by presenting the multifractal theoretical framework and principal
practical methods, namely the moment method, the histogram method, multifractal
detrended fluctuation analysis (MDFA) and modulus maxima wavelet transform
(MMWT), with a comparative and interpretative eye.


title:
Local resilience for squares of almost spanning cycles in sparse random
  graphs

abstract:
  In 1962, P\'osa conjectured that a graph $G=(V, E)$ contains a square of a
Hamiltonian cycle if $\delta(G)\ge 2n/3$. Only more than thirty years later
Koml\'os, S\'ark\H{o}zy, and Szemer\'edi proved this conjecture using the
so-called Blow-Up Lemma. Here we extend their result to a random graph setting.
We show that for every $\epsilon > 0$ and $p=n^{-1/2+\epsilon}$ a.a.s. every
subgraph of $G_{n,p}$ with minimum degree at least $(2/3+\epsilon)np$ contains
the square of a cycle on $(1-o(1))n$ vertices. This is almost best possible in
three ways: (1) for $p\ll n^{-1/2}$ the random graph will not contain any
square of a long cycle (2) one cannot hope for a resilience version for the
square of a spanning cycle (as deleting all edges in the neighborhood of single
vertex destroys this property) and (3) for $c<2/3$ a.a.s. $G_{n,p}$ contains a
subgraph with minimum degree at least $cnp$ which does not contain the square
of a path on $(1/3+c)n$ vertices.


title:
Isogeometric computation reuse method for complex objects with
  topology-consistent volumetric parameterization

abstract:
  Volumetric spline parameterization and computational efficiency are two main
challenges in isogeometric analysis (IGA). To tackle this problem, we propose a
framework of computation reuse in IGA on a set of three-dimensional models with
similar semantic features. Given a template domain, B-spline based consistent
volumetric parameterization is first constructed for a set of models with
similar semantic features. An efficient quadrature-free method is investigated
in our framework to compute the entries of stiffness matrix by Bezier
extraction and polynomial approximation. In our approach, evaluation on the
stiffness matrix and imposition of the boundary conditions can be pre-computed
and reused during IGA on a set of CAD models. Examples with complex geometry
are presented to show the effectiveness of our methods, and efficiency similar
to the computation in linear finite element analysis can be achieved for IGA
taken on a set of models.


title: Sequence-to-Sequence Learning as Beam-Search Optimization

abstract:
  Sequence-to-Sequence (seq2seq) modeling has rapidly become an important
general-purpose NLP tool that has proven effective for many text-generation and
sequence-labeling tasks. Seq2seq builds on deep neural language modeling and
inherits its remarkable accuracy in estimating local, next-word distributions.
In this work, we introduce a model and beam-search training scheme, based on
the work of Daume III and Marcu (2005), that extends seq2seq to learn global
sequence scores. This structured approach avoids classical biases associated
with local training and unifies the training loss with the test-time usage,
while preserving the proven model architecture of seq2seq and its efficient
training approach. We show that our system outperforms a highly-optimized
attention-based seq2seq system and other baselines on three different sequence
to sequence tasks: word ordering, parsing, and machine translation.


title: Boundary homogenization for a triharmonic intermediate problem

abstract:
  We consider the triharmonic operator subject to homogeneous boundary
conditions of intermediate type on a bounded domain of the N-dimensional
Euclidean space. We study its spectral behaviour when the boundary of the
domain undergoes a perturbation of oscillatory type. We identify the
appropriate limit problems which depend on whether the strength of the
oscillation is above or below a critical threshold. We analyse in detail the
critical case which provides a typical homogenization problem leading to a
strange boundary term in the limit problem.


title:
Transit timing variation and transmission spectroscopy analyses of the
  hot Neptune GJ3470b

abstract:
  GJ3470b is a hot Neptune exoplanet orbiting an M dwarf and the first
sub-Jovian planet to exhibit Rayleigh scattering. We present transit timing
variation (TTV) and transmission spectroscopy analyses of multi-wavelength
optical photometry from 2.4-m and 0.5-m telescopes at the Thai National
Observatory, and the 0.6-m PROMPT-8 telescope in Chile. Our TTV analysis allows
us to place an upper mass limit for a second planet in the system. The presence
of a hot Jupiter with a period of less than 10 days or a planet with an orbital
period between 2.5 and 4.0 days are excluded. Combined optical and
near-infrared transmission spectroscopy favour an H/He dominated haze (mean
molecular weight 1.08$\pm$0.20) with high particle abundance at high altitude.
We also argue that previous near-infrared data favour the presence of methane
in the atmosphere of GJ3470b.


title:
Oxygen Point Defect Chemistry in Ruddlesden-Popper Oxides
  (La$_{1-x}$Sr$_{x}$)$_{2}$MO$_{4{\pm}{\delta}}$ (M = Co, Ni, Cu)

abstract:
  Stability of oxygen point defects in Ruddlesden-Popper oxides
(La$_{1-x}$Sr$_{x}$)$_{2}$MO$_{4{\pm}{\delta}}$ (M = Co, Ni, Cu) is studied
with density functional theory calculations to determine their stable sites,
charge states, and energetics as functions of Sr content ($x$), transition
metal (M) and defect concentration ({\delta}). We demonstrate that the dominant
O point defects can change between oxide interstitials, peroxide interstitials,
and vacancies. Generally, increasing $x$ and atomic number of M stabilizes
peroxide over oxide interstitials, as well as vacancies over both peroxide and
oxide interstitials; increasing {\delta} destabilizes both oxide interstitials
and vacancies, but affects little peroxide interstitials. We also demonstrate
that the O 2$p$-band center is a powerful descriptor for these materials and
correlates linearly with the formation energy of all the defects. The trends of
formation energy versus $x$, M and {\delta} and the correlation with O
2$p$-band center are explained in terms of oxidation chemistry and electronic
structure.


title: Search for an Isospin I =3 Dibaryon

abstract:
  Various theoretical calculations based on QCD or hadronic interactions
predict that in addition to the recently observed dibaryon resonance
$d^*(2380)$ with $I(J^P) = 0(3^+)$ there should also exist a dibaryon resonance
with mirrored quantum numbers $I(J^P) = 3(0^+)$. We report here on a search for
such a $NN$-decoupled state in data on the $pp \to pp\pi^+\pi^+\pi^-\pi^-$
reaction. Since no clear-cut evidence has been found, we give upper limits for
the production cross section of such a resonance in the mass range 2280 - 2500
MeV.


title:
A Natural Probabilistic Model on the Integers and its Relation to
  Dickman-Type Distributions and Buchstab's Function

abstract:
  Let $\{p_j\}_{j=1}^\infty$ denote the set of prime numbers in increasing
order, let $\Omega_N\subset \mathbb{N}$ denote the set of positive integers
with no prime factor larger than $p_N$ and let $P_N$ denote the probability
measure on $\Omega_N$ which gives to each $n\in\Omega_N$ a probability
proportional to $\frac1n$. This measure is in fact the distribution of the
random integer $I_N\in\Omega_N$ defined by $I_N=\prod_{j=1}^Np_j^{X_{p_j}}$,
where $\{X_{p_j}\}_{j=1}^\infty$ are independent random variables and $X_{p_j}$
is distributed as Geom$(1-\frac1{p_j})$. We show that $\frac{\log n}{\log N}$
under $P_N$ converges weakly to the Dickman distribution. Let
$D_{\text{nat}}(A)$ denote the natural density of $A\subset\mathbb{N}$, if it
exists, and let $D_{\text{log-indep}}(A)=\lim_{N\to\infty}P_N(A\cap\Omega_N)$
denote the density of $A$ arising from $\{P_N\}_{N=1}^\infty$, if it exists. We
show that the two densities coincide on a natural algebra of subsets of
$\mathbb{N}$. We also show that they do not agree on the sets of
$n^\frac1s$-\it smooth numbers \rm\ $\{n\in\mathbb{N}: p^+(n)\le n^\frac1s\}$,
$s>1$, where $p^+(n)$ is the largest prime divisor of $n$. This last
consideration concerns distributions involving the Dickman function. We also
consider the sets of $n^\frac1s$-\it rough numbers \rm\
$\{n\in\mathbb{N}:p^-(n)\ge n^{\frac1s}\}$, $s>1$, where $p^-(n)$ is the
smallest prime divisor of $n$. We show that the probabilities of these sets,
under the uniform distribution on $[N]=\{1,\ldots, N\}$ and under the
$P_N$-distribution on $\Omega_N$, have the same asymptotic decay profile as
functions of $s$, although their rates are necessarily different. This profile
involves the Buchstab function. We also prove a new representation for the
Buchstab function.


title:
'Half-bare' positron in the inner gap of a pulsar and shift of inter
  pulse position

abstract:
  The pulsed radiation from the Crab pulsar consists of the main pulse (MP) and
inter pulse (IP), as well as of the extra pulse components appearing at certain
frequencies. It has been studied at many frequencies and contains unique
information, which is not available for the majority of the pulsars. One of the
mysteries of these data, found by Moffett and Hankins twenty years ago, is the
shift of the IP at high radio frequencies compared to lower ones and return to
its previous position in the more high-frequency optical and X-ray range. We
propose the explanation of these mysterious changes with the frequency through
reflection of radiation by relativistic positrons from the star surface. The
magnetic field of the pulsar in the pole must be inclined to the surface of the
star and affects on the discussed processes. The positrons, which are
accelerated towards the surface of the star by the inner gap electric field,
radiate as half-bare particles. The spectral-angular properties of this
radiation differ from those ones of the electron curvature radiation inside the
gap.


title: Approximately coloring graphs without long induced paths

abstract:
  It is an open problem whether the 3-coloring problem can be solved in
polynomial time in the class of graphs that do not contain an induced path on
$t$ vertices, for fixed $t$. We propose an algorithm that, given a 3-colorable
graph without an induced path on $t$ vertices, computes a coloring with
$\max\{5,2\lceil{\frac{t-1}{2}}\rceil-2\}$ many colors. If the input graph is
triangle-free, we only need $\max\{4,\lceil{\frac{t-1}{2}}\rceil+1\}$ many
colors. The running time of our algorithm is $O((3^{t-2}+t^2)m+n)$ if the input
graph has $n$ vertices and $m$ edges.


title:
Competing effects at Pt/YIG interfaces: spin Hall magnetoresistance,
  magnon excitations and magnetic frustration

abstract:
  We study the spin Hall magnetoresistance (SMR) and the magnon spin transport
(MST) in Pt/Y3Fe5O12(YIG)-based devices with intentionally modified interfaces.
Our measurements show that the surface treatment of the YIG film results in a
slight enhancement of the spin-mixing conductance and an extraordinary increase
in the efficiency of the spin-to-magnon excitations at room temperature. The
surface of the YIG film develops a surface magnetic frustration at low
temperatures, causing a sign change of the SMR and a dramatic suppression of
the MST. Our results evidence that SMR and MST could be used to explore
magnetic properties of surfaces, including those with complex magnetic
textures, and stress the critical importance of the non-magnetic/ferromagnetic
interface properties in the performance of the resulting spintronic devices.


title:
AdS/QCD approach to the scale-invariant extension of the standard model
  with a strongly interacting hidden sector

abstract:
  In this paper, we revisit a scale-invariant extension of the standard model
(SM) with a strongly interacting hidden sector within AdS/QCD approach. Using
the AdS/QCD, we reduce the number of input parameters to three, {\it i.e.}
hidden pion decay constant, hidden pion mass and $\tan\beta$ that is defined as
the ratio of the vacuum expectation values (VEV) of the singlet scalar field
and the SM Higgs boson. As a result, our model has sharp predictability. We
perform the phenomenological analysis of the hidden pions which is one of the
dark matter (DM) candidates in this model. With various theoretical and
experimental constraints we search for the allowed parameter space and find
that both resonance and non-resonance solutions are possible. Some typical
correlations among various observables such as thermal relic density of hidden
pions, Higgs boson signal strengths and DM-nucleon cross section are
investigated. We provide some benchmark points for experimental tests.


title: A study of the resonances $K_{0}^{*}(800)$ and $K_{0}^{*}(1430)$

abstract:
  We study the scalar kaonic states $K_{0}^{\ast}(800)$ and
$K_{0}^{\ast}(1430)$ by using a relativistic QFT Lagrangian in which only a
single kaonic field corresponding to the well-established scalar state
$K_{0}^{\ast}(1430)$ is considered and in which both derivative and
non-derivative interaction terms are taken into account. Even if the scalar
spectral function shows a unique peak close to $1.4$ GeV, we find two poles in
the complex plane: $1.413\pm0.002-i(0.127\pm0.003)$ GeV, which is related to
the seed quark-antiquark state $K_{0}^{\ast}(1430),$ and
$0.746\pm0.019-i(262\pm0.014)$ GeV, which is an additional companion pole
related to $K_{0}^{\ast}(800)$. As a further investigation for increasing
$N_{c}$ confirms, $K_{0}^{\ast}(800)$ emerges as a dynamically generated
four-quark object as a consequence of pion-kaon loops.


title:
Structural Relaxation and Aging Scaling in the Coulomb and Bose Glass
  Models

abstract:
  We employ Monte Carlo simulations to study the relaxation properties of the
two-dimensional Coulomb glass in disordered semiconductors and the
three-dimensional Bose glass in type-II superconductors in the presence of
extended linear defects. We investigate the effects of adding non-zero random
on-site energies from different distributions on the properties of the
correlation-induced Coulomb gap in the density of states (DOS) and on the
non-equilibrium aging kinetics highlighted by the density autocorrelation
functions. We also probe the sensitivity of the system's equilibrium and
non-equilibrium relaxation properties to instantaneous changes in the density
of charge carriers in the Coulomb glass or flux lines in the Bose glass.

categories: cond-mat.stat-mech cond-mat.dis-nn cond-mat.str-el cond-mat.supr-con


title:
Field-tuned order by disorder in Ising frustrated magnets with
  antiferromagnetic interactions

abstract:
  We demonstrate the appearance of thermal order by disorder in Ising
pyrochlores with staggered antiferromagnetic order frustrated by an applied
magnetic field. We use a mean-field cluster variational method, a
low-temperature expansion and Monte Carlo simulations to characterise the
order-by-disorder transition. By direct evaluation of the density of states we
quantitatively show how a symmetry-broken state is selected by thermal
excitations. We discuss the relevance of our results to experiments in $2d$ and
$3d$ samples, and evaluate how anomalous finite-size effects could be exploited
to detect this phenomenon experimentally in two-dimensional artificial systems,
or in antiferromagnetic all-in--all-out pyrochlores like Nd$_2$Hf$_2$O$_7$ or
Nd$_2$Zr$_2$O$_7$, for the first time.


title:
On recurrence and availability factor for single--server system with
  general arrivals

abstract:
  Recurrence and ergodic properties are established for a single--server
queueing system with variable intensities of arrivals and service. Convergence
to stationarity is also interpreted in terms of reliability theory.


title:
Postulation of generic lines and one double line in $\PP^n$ in view of
  generic lines and one multiple linear space

abstract:
  A well-known theorem by Hartshorne--Hirschowitz (\cite{HH}) states that a
generic union $\mathbb{X}\subset \PP^n$, $n\geq 3$, of lines has good
postulation with respect to the linear system $|\OO_{\PP^n}(d)|$. So a question
that arises naturally in studying the postulation of non-reduced positive
dimensional schemes supported on linear spaces is the question whether adding a
$m$-multiple linear space $m\PP^r$ to $\mathbb{X}$ can still preserve it's good
postulation, which means in classical language that, whether $m\PP^r$ imposes
independent conditions on the linear system $|\II_{\mathbb{X}}(d)|$. Recently,
the case of $r=0$, i.e., the case of lines and one $m$-multiple point, has been
completely solved by several authors (\cite{CCG4}, \cite{AB}, \cite{B1})
starting with Carlini--Catalisano--Geramita, while the case of $r>0$ was
remained unsolved, and this is what we wish to investigate in this paper.
Precisely, we study the postulation of a generic union of $s$ lines and one
$m$-multiple linear space $m\PP^r$ in $\PP^n$, $n\geq r+2$. Our main purpose is
to provide a complete answer to the question in the case of lines and one
double line, which says that the double line imposes independent conditions on
$|\II_{\mathbb{X}}(d)|$ except for the only case $\{n=4, s=2, d=2\}$.
  Moreover, we discuss an approach to the general case of lines and one
$m$-multiple linear space, $(m\geq 2, r\geq 1)$, particularly, we find several
exceptional such schemes, and we conjecture that these are the only exceptional
ones in this family. Finally, we give some partial results in support of our
conjecture.


title: An automata characterisation for multiple context-free languages

abstract:
  We introduce tree stack automata as a new class of automata with storage and
identify a restricted form of tree stack automata that recognises exactly the
multiple context-free languages.


title:
Large scale biomedical texts classification: a kNN and an ESA-based
  approaches

abstract:
  With the large and increasing volume of textual data, automated methods for
identifying significant topics to classify textual documents have received a
growing interest. While many efforts have been made in this direction, it still
remains a real challenge. Moreover, the issue is even more complex as full
texts are not always freely available. Then, using only partial information to
annotate these documents is promising but remains a very ambitious issue.
MethodsWe propose two classification methods: a k-nearest neighbours
(kNN)-based approach and an explicit semantic analysis (ESA)-based approach.
Although the kNN-based approach is widely used in text classification, it needs
to be improved to perform well in this specific classification problem which
deals with partial information. Compared to existing kNN-based methods, our
method uses classical Machine Learning (ML) algorithms for ranking the labels.
Additional features are also investigated in order to improve the classifiers'
performance. In addition, the combination of several learning algorithms with
various techniques for fixing the number of relevant topics is performed. On
the other hand, ESA seems promising for this classification task as it yielded
interesting results in related issues, such as semantic relatedness computation
between texts and text classification. Unlike existing works, which use ESA for
enriching the bag-of-words approach with additional knowledge-based features,
our ESA-based method builds a standalone classifier. Furthermore, we
investigate if the results of this method could be useful as a complementary
feature of our kNN-based approach.ResultsExperimental evaluations performed on
large standard annotated datasets, provided by the BioASQ organizers, show that
the kNN-based method with the Random Forest learning algorithm achieves good
performances compared with the current state-of-the-art methods, reaching a
competitive f-measure of 0.55% while the ESA-based approach surprisingly
yielded reserved results.ConclusionsWe have proposed simple classification
methods suitable to annotate textual documents using only partial information.
They are therefore adequate for large multi-label classification and
particularly in the biomedical domain. Thus, our work contributes to the
extraction of relevant information from unstructured documents in order to
facilitate their automated processing. Consequently, it could be used for
various purposes, including document indexing, information retrieval, etc.


title:
Multiphasic profiles for voltage-dependent K+ channels: Reanalysis of
  data of MacKinnon and coworkers

abstract:
  In a study of the role that voltage-dependent K+ channels may have in the
mechanosensation of living cells (Schmidt et al. Proc Soc Natl Acad Sci USA
109: 10352-10357. 2012), the data were as conventionally done fitted by a
Boltzmann function. However, as also found for other data for ion channels,
this interpretation must be rejected in favor of a multiphasic profile, a
series of straight lines separated by discontinuous transitions, quite often in
the form of noncontiguities (jumps). The data points in the present study are
often very unevenly distributed around the curvilinear profiles. Thus, for 43
of the 75 profiles, the probability is less than 5% that the uneven
distribution is due to chance, for 26 the probability is less than 1%, and for
12 the probability is less than 0.1%, giving a vanishingly low overall
probability for all profiles. Especially at low voltages, the differences
between the fits to curvilinear and multiphasic profiles may be huge. In the
multiphasic profiles, adjacent lines are quite often parallel or nearly so, in
which case the transitions are, necessarily, in the form of jumps. The lines in
the multiphasic profiles appear to be perfectly straight, with no indication of
any curvilinearity. The r values are for the most part high, quite often
exceedingly high. In addition to activation of ion channels, a wide variety of
biological as well as non-biological processes and phenomena involving binding,
pH, folding/unfolding and effect of chain length can be well represented by
multiphasic profiles (Nissen 2015a,b, 2016. Posted on arXiv.org with Paper ID
arXiv: 1511.06601, 1512.02561 and 1603.05144). Introduction


title:
Bounds for the traveling salesman paths of two-dimensional modular
  lattices

abstract:
  We present tight upper and lower bounds for the traveling salesman path
through the points of two-dimensional modular lattices. We use these results to
bound the traveling salesman path of two-dimensional Kronecker point sets. Our
results rely on earlier work on shortest vectors in lattices as well as on the
strong convergence of Jacobi-Perron type algorithms.


title:
Generative Topic Embedding: a Continuous Representation of Documents
  (Extended Version with Proofs)

abstract:
  Word embedding maps words into a low-dimensional continuous embedding space
by exploiting the local word collocation patterns in a small context window. On
the other hand, topic modeling maps documents onto a low-dimensional topic
space, by utilizing the global word collocation patterns in the same document.
These two types of patterns are complementary. In this paper, we propose a
generative topic embedding model to combine the two types of patterns. In our
model, topics are represented by embedding vectors, and are shared across
documents. The probability of each word is influenced by both its local context
and its topic. A variational inference method yields the topic embeddings as
well as the topic mixing proportions for each document. Jointly they represent
the document in a low-dimensional continuous space. In two document
classification tasks, our method performs better than eight existing methods,
with fewer features. In addition, we illustrate with an example that our method
can generate coherent topics even based on only one document.


title: Strangeness suppression in the unquenched quark model

abstract:
  In this contribution, we discuss the strangeness suppression in the proton in
the framework of the unquenched quark model. The theoretical results are in
good agreement with the values extracted from CERN and JLab experiments.


title: Modifying the pion mass in the loosely bound Skyrme model

abstract:
  We study the loosely bound Skyrme model with the addition of two different
pion mass terms; this is the most general potential of polynomial form up to
second order in the trace of the Skyrme field. The two pion mass terms are
called the standard pion mass term and the modified pion mass term. We find
that the binding energies are not reduced by the introduction of the modified
pion mass, but it is analogous to the standard pion mass term with a decrease
in the value of the mass parameter of the loosely bound potential (for large
values of the latter parameter). We find by increasing the overall pion mass
that we can reduce the classical binding energy of the 4-Skyrmion to the 2.7%
level and the total binding energy including the contribution from spin/isospin
quantization is reduced to the 5.8% level.


title:
Hypergeometric Expressions for Generating Functions of Walks with Small
  Steps in the Quarter Plane

abstract:
  We study nearest-neighbors walks on the two-dimensional square lattice, that
is, models of walks on $\mathbb{Z}^2$ defined by a fixed step set that is a
subset of the non-zero vectors with coordinates 0, 1 or $-1$. We concern
ourselves with the enumeration of such walks starting at the origin and
constrained to remain in the quarter plane $\mathbb{N}^2$, counted by their
length and by the position of their ending point. Bousquet-M\'elou and Mishna
[Contemp. Math., pp. 1--39, Amer. Math. Soc., 2010] identified 19 models of
walks that possess a D-finite generating function; linear differential
equations have then been guessed in these cases by Bostan and Kauers [FPSAC
2009, Discrete Math. Theor. Comput. Sci. Proc., pp. 201--215, 2009]. We give
here the first proof that these equations are indeed satisfied by the
corresponding generating functions. As a first corollary, we prove that all
these 19 generating functions can be expressed in terms of Gauss'
hypergeometric functions that are intimately related to elliptic integrals. As
a second corollary, we show that all the 19 generating functions are
transcendental, and that among their $19 \times 4$ combinatorially meaningful
specializations only four are algebraic functions.


title:
Microscopic interpretation of the Dynes formula for the tunneling
  density of states

abstract:
  Excellent fits of the tunneling density of states in disordered
superconductors can be often achieved making use of the phenomenological Dynes
formula. However, no consistent derivation of this formula has been available
so far. The Dynes formula can be interpreted by the simplest causal
frequency-dependent gap function $\Delta(\omega)$ with a vanishing gap at the
Fermi level. Here we show, within the coherent potential approximation, that
precisely such gap function describes superconductors with a Lorentzian
distribution of pair-breaking fields and arbitrary potential disorder. We
predict spectral and thermodynamic properties of such superconductors.


title: Fluctuation Relation for Qubit-Calorimetry

abstract:
  Motivated by proposed thermometry measurement on an open quantum system, we
present a simple model of an externally driven qubit interacting with a finite
sized, fermion environment acting as calorimeter. The derived dynamics is
governed by a stochastic Schr\"odinger equation coupled to the temperature
change of the calorimeter. We prove a fluctuation relation and deduce from it a
notion of entropy production. Finally, we discuss the first and second law
associated to the dynamics.


title:
Anomalous electronic heat capacity of copper nanowires at sub-kelvin
  temperatures

abstract:
  We have measured the electronic heat capacity of thin film nanowires of
copper and silver at temperatures 0.1 - 0.3 K; the films were deposited by
standard electron-beam evaporation. The specific heat of the Ag films of
sub-100 nm thickness agrees with the bulk value and the free-electron estimate,
whereas that of similar Cu films exceeds the corresponding reference values by
one order of magnitude. The origin of the anomalously high heat capacity of
copper films remains unknown for the moment. Based on the low heat capacity and
the possibility to devise a tunnel probe thermometer on it, the Ag films form a
promising absorber material, e.g., for micro-wave photon calorimetry.


title:
Temperature Overloads in Power Grids Under Uncertainty: a Large
  Deviations Approach

abstract:
  The advent of renewable energy has huge implications for the design and
control of power grids. Due to increasing supply-side uncertainty, traditional
reliability constraints such as strict bounds on current, voltage and
temperature in a transmission line have to be replaced by computationally
demanding chance constraints. In this paper we use large deviations techniques
to study the probability of current and temperature overloads in power grids
with stochastic power injections, and develop corresponding safe capacity
regions. In particular, we characterize the set of admissible power injections
such that the probability of overloading of any line over a given time interval
stays below a fixed target. We show how enforcing (stochastic) constraints on
temperature, rather than on current, results in a less conservative approach
and can thus lead to capacity gains.


title:
Cosmic constraint on massive neutrinos in viable f(R) gravity with
  producing LCDM background expansion

abstract:
  Tensions between several cosmic observations were found recently, such as the
inconsistent values of $H_{0}$ (or $\sigma_{8}$) were indicated by the
different cosmic observations. Introducing the massive neutrinos in
$\Lambda$CDM could potentially solve the tensions. Viable $f(R)$ gravity
producing $\Lambda$CDM background expansion with massive neutrinos is
investigated in this paper. We fit the current observational data: Planck-2015
CMB, RSD, BAO and SNIa to constrain the mass of neutrinos in viable $f(R)$
theory. The constraint results at 95\% confidence level are: $\Sigma
m_\nu<0.202$ eV for the active neutrino case, $m_{\nu, sterile}^{eff}<0.757$ eV
with $N_{eff}<3.22$ for the sterile neutrino case. For the effects by the mass
of neutrinos, the constraint results on model parameter at 95\% confidence
level become $f_{R0}\times 10^{-6}> -1.89$ and $f_{R0}\times 10^{-6}> -2.02$
for two cases, respectively. It is also shown that the fitting values of
several parameters much depend on the neutrino properties, such as the cold
dark matter density, the cosmological quantities at matter-radiation equality,
the neutrino density and the fraction of baryonic mass in helium. At last, the
constraint result shows that the tension between direct and CMB measurements of
$H_0$ gets slightly weaker in the viable $f(R)$ model than that in the base
$\Lambda$CDM model.


title: Collective magnetic splitting in single-photon superradiance

abstract:
  In an ensemble of identical atoms, cooperative effects like sub- or
superradiance may alter the decay rates and the energy of specific transitions
may be shifted from the single-atom value by the so-called collective Lamb
shift. While such effects in ensembles of two-level systems are by now well
understood, realistic multi-level systems are more difficult to handle. In this
work we show that in a system of atoms or nuclei under the action of an
external magnetic field, the collective contribution to the level shifts can
amount to seizable deviations from the single-atom Zeeman or magnetic hyperfine
splitting picture. We develop a formalism to describe single-photon
superradiance in multi-level systems in the small sample limit and quantify the
parameter regime for which the collective Lamb shift leads to measurable
deviations in the magnetic-field-induced splitting. In particular, we show that
this effect should be observable in the nuclear magnetic hyperfine splitting in
M\"ossbauer nuclei embedded in thin-film x-ray cavities.


title: Strongly self-interacting processes on the circle

abstract:
  The purpose of this paper is to investigate the long time behaviour for a
self-interacting diffusion and a self-interacting velocity jump process. While
the diffusion case has already been studied for some particular potential
function, the second one, which belongs to the family of piecewise
deterministic processes, is new.
  Depending on the underlying potential function's shape, we prove either the
almost sure convergence or the recurrence for a natural extended process given
by a change a variable.


title:
Fine- and hyperfine-structure effects in molecular photoionization: I.
  General theory and direct photoionization

abstract:
  We develop a model for predicting fine- and hyperfine intensities in the
direct photoionization of molecules based on the separability of electron and
nuclear spin states from vibrational-electronic states. Using spherical tensor
algebra, we derive highly symmetrized forms of the squared photoionization
dipole matrix elements from which which we derive the salient selection and
propensity rules for fine- and hyperfine resolved photoionizing transitions.
Our theoretical results are validated by the analysis of the fine-structure
resolved photoelectron spectrum of O$_2$ (reported by H. Palm and F. Merkt,
Phys. Rev. Lett. 81, 1385 (1998)) and are used for predicting hyperfine
populations of molecular ions produced by photoionization.


title:
Subgroups of Spin(7) or SO(7) with each element conjugate to some
  element of G_2, and applications to automorphic forms

abstract:
  As is well-known, the compact groups Spin(7) and SO(7) both have a single
conjugacy class of compact subgroups of exceptional type G_2. We first show
that if H is a subgroup of Spin(7), and if each element of H is conjugate to
some element of G_2, then H itself is conjugate to a subgroup of G_2. The
analogous statement for SO(7) turns out be false, and our main result is a
classification of all the exceptions. They are the following groups, embedded
in each case in SO(7) in a very specific way: GL_2(Z/3Z), SL_2(Z/3Z), Z/4Z x
Z/2Z, as well as the nonabelian subgroups of GO_2(C) with compact closure,
similitude factors group {-1,1}, and which are not isomorphic to the dihedral
group of order 8. More generally, we consider the analogous problems in which
the Euclidean space is replaced by a quadratic space of dimension 7 over an
arbitrary field.
  This type of questions naturally arises in some formulation of a converse
statement of Langlands' global functoriality conjecture, to which the results
above have thus some applications. Moreover, we give necessary and sufficient
local conditions on a cuspidal algebraic regular automorphic representation of
GL_7 over a totally real number field so that its associated \ell-adic Galois
representations can be conjugate into G_2(\bar{Q_\ell}).


title:
Stabilization with target oriented control for higher order difference
  equations

abstract:
  For a physical or biological model whose dynamics is described by a higher
order difference equation $u_{n+1}=f(u_n,u_{n-1}, \dots, u_{n-k+1})$, we
propose a version of a target oriented control $u_{n+1}=cT+(1-c)f(u_n,u_{n-1},
\dots, u_{n-k+1})$, with $T\ge 0$, $c\in [0,1)$. In ecological systems, the
method incorporates harvesting and recruitment and for a wide class of $f$,
allows to stabilize (locally or globally) a fixed point of $f$. If a point
which is not a fixed point of $f$ has to be stabilized, the target oriented
control is an appropriate method for achieving this goal. As a particular case,
we consider pest control applied to pest populations with delayed
density-dependence. This corresponds to a proportional feedback method, which
includes harvesting only, for higher order equations.


title:
A Wide-Field Survey for Transiting Hot Jupiters and Eclipsing
  Pre-Main-Sequence Binaries in Young Stellar Associations

abstract:
  The past two decades have seen a significant advancement in the detection,
classification and understanding of exoplanets and binaries. This is due, in
large part, to the increase in use of small-aperture telescopes (< 20 cm) to
survey large areas of the sky to milli-mag precision with rapid cadence. The
vast majority of the planetary and binary systems studied to date consist of
main-sequence or evolved objects, leading to a dearth of knowledge of
properties at early times (< 50 Myr). Only a dozen binaries and one candidate
transiting Hot Jupiter are known among pre-main sequence objects, yet these are
the systems that can provide the best constraints on stellar formation and
planetary migration models. The deficiency in the number of well-characterized
systems is driven by the inherent and aperiodic variability found in
pre-main-sequence objects, which can mask and mimic eclipse signals. Hence, a
dramatic increase in the number of young systems with high-quality observations
is highly desirable to guide further theoretical developments. We have recently
completed a photometric survey of 3 nearby (< 150 pc) and young (< 50 Myr)
moving groups with a small aperture telescope. While our survey reached the
requisite photometric precision, the temporal coverage was insufficient to
detect Hot Jupiters. Nevertheless, we discovered 346 pre-main-sequence binary
candidates, including 74 high-priority objects for further study.


title:
Evolution of the Wasserstein distance between the marginals of two
  Markov processes

abstract:
  In this paper, we are interested in the time derivative of the Wasserstein
distance between the marginals of two Markov processes. As recalled in the
introduction, the Kantorovich duality leads to a natural candidate for this
derivative. Up to the sign, it is the sum of the integrals with respect to each
of the two marginals of the corresponding generator applied to the
corresponding Kantorovich potential. For pure jump processes with bounded
intensity of jumps, we prove that the evolution of the Wasserstein distance is
actually given by this candidate. In dimension one, we show that this remains
true for Piecewise Deterministic Markov Processes. We apply the formula to
estimate the exponential decrease rate of the Wasserstein distance between the
marginals of two birth and death processes with the same generator in terms of
the Wasserstein curvature.


title:
Enabling Secure and Usable Mobile Application: Revealing the Nuts and
  Bolts of software TPM in todays Mobile Devices

abstract:
  The emergence of mobile applications to execute sensitive operations has
brought a myriad of security threats to both enterprises and users. In order to
benefit from the large potential in smartphones there is a need to manage the
risks arising from threats, while maintaining an easy interface for the users.
In this paper we investigate the use of Trusted Platform Model (TPM) 2.0 to
develop a secure application for smartphones using Windows Phone 8.1. In
particular, we suggest a framework based on remote attestation as a proxy to
authenticate remote services, where the device is associated to the user and
replaces the users credentials. In addition, we use the TPM 2.0 to enable
secured information and data storage within the device itself. We present an
implementation and performance evaluation of the suggested architecture that
uses our novel attestation and authentication scheme and reveal the caveats of
using software TPM in todays mobile devices.


title: The Instanton-Dyon Liquid Model V: Twisted Light Quarks

abstract:
  We discuss an extension of the instanton-dyon liquid model that includes
twisted light quarks in the fundamental representation with explicit $Z_{N_c}$
symmetry for the case with equal number of colors $N_c$ and flavors $N_f$. We
map the model on a 3-dimensional quantum effective theory, and analyze it in
the mean-field approximation. The effective potential and the vacuum chiral
condensates are made explicit for $N_f=N_c=2, 3$. The low temperature phase is
center symmetric but breaks spontaneously flavor symmetry with $N_f-1$ massless
pions. The high temperature phase breaks center symmetry but supports finite
and unequal quark condensates.


title: Out of equilibrium density dynamics of a quenched fermionic system

abstract:
  Using a Luttinger liquid theory we investigate the time evolution of the
particle density of a one-dimensional fermionic system with open boundaries and
subject to a finite duration quench of the inter-particle interaction. We
provide analytical and asymptotic solutions to the unitary time evolution of
the system, showing that both switching on and switching off the quench ramp
create light-cone perturbations in the density. The post-quench dynamics is
strongly affected by the interference between these two perturbations. In
particular, we find that the discrepancy between the time-dependent density and
the one obtained by a generalized Gibbs ensemble picture vanishes with an
oscillatory behavior as a function of the quench duration, with local minima
corresponding to a perfect overlap of the two light-cone perturbations. For
adiabatic quenches, we also obtain a similar behavior in the approach of the
generalized Gibbs ensemble density towards the one associated with the ground
state of the final Hamiltonian.


title:
Hybrid quantum device with nitrogen-vacancy centers in diamond coupled
  to carbon nanotubes

abstract:
  We show that nitrogen-vacancy (NV) centers in diamond interfaced with a
suspended carbon nanotube carrying a dc current can facilitate a
spin-nanomechanical hybrid device. We demonstrate that strong magnetomechanical
interactions between a single NV spin and the vibrational mode of the suspended
nanotube can be engineered and dynamically tuned by external control over the
system parameters. This spin-nanomechanical setup with strong, \emph{intrinsic}
and \emph{tunable} magnetomechanical couplings allows for the construction of
hybrid quantum devices with NV centers and carbon-based nanostructures, as well
as phonon-mediated quantum information processing with spin qubits.


title: Numerical Relativity Beyond Astrophysics

abstract:
  Though the main applications of computer simulations in relativity are to
astrophysical systems such as black holes and neutron stars, nonetheless there
are important applications of numerical methods to the investigation of general
relativity as a fundamental theory of the nature of space and time. This paper
gives an overview of some of these applications. In particular we cover (i)
investigations of the properties of spacetime singularities such as those that
occur in the interior of black holes and in big bang cosmology. (ii)
investigations of critical behavior at the threshold of black hole formation in
gravitational collapse. (iii) investigations inspired by string theory, in
particular analogs of black holes in more than 4 spacetime dimensions and
gravitational collapse in spacetimes with a negative cosmological constant.


title:
On Projected Stochastic Gradient Descent Algorithm with Weighted
  Averaging for Least Squares Regression

abstract:
  The problem of least squares regression of a $d$-dimensional unknown
parameter is considered. A stochastic gradient descent based algorithm with
weighted iterate-averaging that uses a single pass over the data is studied and
its convergence rate is analyzed. We first consider a bounded constraint set of
the unknown parameter. Under some standard regularity assumptions, we provide
an explicit $O(1/k)$ upper bound on the convergence rate, depending on the
variance (due to the additive noise in the measurements) and the size of the
constraint set. We show that the variance term dominates the error and
decreases with rate $1/k$, while the term which is related to the size of the
constraint set decreases with rate $\log k/k^2$. We then compare the asymptotic
ratio $\rho$ between the convergence rate of the proposed scheme and the
empirical risk minimizer (ERM) as the number of iterations approaches infinity.
We show that $\rho\leq 4$ under some mild conditions for all $d\geq 1$. We
further improve the upper bound by showing that $\rho\leq 4/3$ for the case of
$d=1$ and unbounded parameter set. Simulation results demonstrate strong
performance of the algorithm as compared to existing methods, and coincide with
$\rho\leq 4/3$ even for large $d$ in practice.


title:
Stochastic Porous Media Equation on General Measure Spaces with
  Increasing Lipschitz Nonlinearties

abstract:
  We prove the existence and uniqueness of probabilistically strong solutions
to stochastic porous media equations driven by time-dependent multiplicative
noise on a general measure space $(E, \mathscr{B}(E), \mu)$, and the Laplacian
replaced by a self-adjoint operator $L$. In the case of Lipschitz
nonlinearities $\Psi$, we in particular generalize previous results for open
$E\subset \mathbb{R}^d$ and $L\!\!=$Laplacian to fractional Laplacians. We also
generalize known results on general measure spaces, where we succeeded in
dropping the transience assumption on $L$, in extending the set of allowed
initial data and in avoiding the restriction to superlinear behavior of $\Psi$
at infinity for $L^2(\mu)$-initial data.


title: MuFuRU: The Multi-Function Recurrent Unit

abstract:
  Recurrent neural networks such as the GRU and LSTM found wide adoption in
natural language processing and achieve state-of-the-art results for many
tasks. These models are characterized by a memory state that can be written to
and read from by applying gated composition operations to the current input and
the previous state. However, they only cover a small subset of potentially
useful compositions. We propose Multi-Function Recurrent Units (MuFuRUs) that
allow for arbitrary differentiable functions as composition operations.
Furthermore, MuFuRUs allow for an input- and state-dependent choice of these
composition operations that is learned. Our experiments demonstrate that the
additional functionality helps in different sequence modeling tasks, including
the evaluation of propositional logic formulae, language modeling and sentiment
analysis.


title:
Muon dynamic radiography of density changes induced by hydrothermal
  activity at the La Soufri\`ere of Guadeloupe volcano

abstract:
  Imaging geological structures through cosmic muon radiography is a newly
developed technique particularly interesting in volcanology. Here we show that
muon radiography may be efficient to detect and characterize mass movements in
shallow hydrothermal systems of low-energy active volcanoes like the La
Soufri\`ere lava dome. We present an experiment conducted on this volcano
during the Summer $2014$ and bring evidence that huge density changes occurred
in three domains of the lava dome. Depending on their position and on the
medium porosity the volumes of these domains vary from $1 \times 10^6 \;
\mathrm{m}^3$ to $7 \times 10^6 \; \mathrm{m}^3$. However, the mass changes
remain quite constant, two of them being negative ($\Delta m \approx -0.6
\times 10^9 \; \mathrm{kg}$) and a third one being positive ($\Delta m \approx
+2 \times 10^9 \; \mathrm{kg}$). We attribute the negative mass changes to the
formation of steam in shallow hydrothermal reservoir previously partly filled
with liquid water. This coincides with the apparition of new fumaroles on top
of the volcano. The positive mass change is synchronized with the negative mass
changes indicating that liquid water probably flowed from the two reservoirs
invaded by steam toward the third reservoir.


title:
Reconciling heat-flux and salt-flux estimates at a melting ice-ocean
  interface

abstract:
  The ratio of heat and salt flux is employed in ice-ocean models to represent
ice-ocean interactions. In this study, this flux ratio is determined from
direct numerical simulations of free convection beneath a melting, horizontal,
smooth ice-ocean interface. We find that the flux ratio at the interface is
three times as large as previously assessed based on turbulent-flux
measurements in the field. As a consequence, interface salinities and melt
rates are overestimated by up to 40\% if they are based on the three-equation
formulation. We also find that the interface flux ratio depends only very
weakly on the far-field conditions of the flow. Lastly, our simulations
indicate that estimates of the interface flux ratio based on direct
measurements of the turbulent fluxes will be difficult because at the interface
the diffusivities alone determine the mixing and the flux ratio varies with
depth. As an alternative, we present a consistent evaluation of the flux ratio
based on the total heat and salt fluxes across the boundary layer and reconcile
the determinations of the ice-ocean interface conditions.


title: Spacetime anisotropy affects cosmological entanglement

abstract:
  Most existing cosmological entanglement studies are focused on the isotropic
Robertson-Walker (RW) spacetime. Here we go beyond this limitation and study
the influence of anisotropy on entanglement generated by dynamical spacetime.
Since the isotropic spacetime is viewed as a background medium and the
anisotropy is incorporated as perturbation, we decompose entanglement entropy
into isotropic and anisotropic contributions. The latter is shown to be
non-negligible by analyzing two cosmological models with weak and conformal
coupling. We also show the possibility of using entanglement to infer about
universe features.


title:
The structure effects in polarization and cross section in inelastic
  A(p,p')X reaction with the 40Ca and 12C nuclei at 1 GeV

abstract:
  The polarization of the secondary protons in inelastic (p,p') reaction on the
40Ca and 12C nuclei at the initial proton energy 1 GeV was measured in the wide
range of the scattered proton momenta at a laboratory angle 21 degree. The
cross section of the reactions were measured as well. The outgoing protons from
the reaction were detected using a magnetic spectrometer equipped with a
multiwire-proportional chambers polarimeter. A structure in the polarization
and cross section data, related probably to scattering of the nucleon
correlation in the nuclei, was observed.


title: Euler-Mahonian statistics and descent bases for semigroup algebras

abstract:
  We consider quotients of the unit cube semigroup algebra by particular
$\mathbb{Z}_r\wr S_n$-invariant ideals. Using Gr\"obner basis methods, we show
that the resulting graded quotient algebra has a basis where each element is
indexed by colored permutations $(\pi,\epsilon)\in\mathbb{Z}_r\wr S_n$ and each
element encodes the negative descent and negative major index statistics on
$(\pi,\epsilon)$. This gives an algebraic interpretation of these statistics
which was previously unknown. This basis of the $\mathbb{Z}_r\wr S_n$-quotients
allows us to recover certain combinatorial identities involving Euler-Mahonian
distributions of statistics.


title: $Z_c(3900)$: Confronting theory and lattice simulations

abstract:
  We consider a recent $T$-matrix analysis by Albaladejo {\it et al.}, [Phys.\
Lett.\ B {\bf 755}, 337 (2016)] which accounts for the $J/\psi\pi$ and
$D^\ast\bar{D}$ coupled--channels dynamics, and that successfully describes the
experimental information concerning the recently discovered $Z_c(3900)^\pm$.
Within such scheme, the data can be similarly well described in two different
scenarios, where the $Z_c(3900)$ is either a resonance or a virtual state. To
shed light into the nature of this state, we apply this formalism in a finite
box with the aim of comparing with recent Lattice QCD (LQCD) simulations. We
see that the energy levels obtained for both scenarios agree well with those
obtained in the single-volume LQCD simulation reported in Prelovsek {\it et
al.} [Phys.\ Rev.\ D {\bf 91}, 014504 (2015)], making thus difficult to
disentangle between both possibilities. We also study the volume dependence of
the energy levels obtained with our formalism, and suggest that LQCD
simulations performed at several volumes could help in discerning the actual
nature of the intriguing $Z_c(3900)$ state.


title: Analysis of constrained 2-body problem

abstract:
  We consider the system of two material points that interact by elastic forces
according to Hooke's law and their motion is restricted to certain curves lying
on the plane. The nonintegrability of this system and idea of the proof are
communicated. Moreover, the analysis of global dynamics by means of Poincar\'e
cross sections is given and local analysis in the neighborhood of an
equilibrium is performed by applying the Birkhoff normal form. Conditions of
linear stability are determined and some particular periodic solutions are
identified.


title: Non-Gaussian entanglement swapping

abstract:
  We investigate the continuous-variable entanglement swapping protocol in a
non-Gaussian setting, with non- Gaussian states employed either as entangled
inputs and/or as swapping resources. The quality of the swapping protocol is
assessed in terms of the teleportation fidelity achievable when using the
swapped states as shared entangled resources in a teleportation protocol. We
thus introduce a two-step cascaded quantum communication scheme that includes a
swapping protocol followed by a teleportation protocol. The swapping protocol
is fed by a general class of tunable non-Gaussian states, the squeezed Bell
states, which, by means of controllable free parameters, allows for a
continuous morphing from Gaussian twin beams up to maximally non-Gaussian
squeezed number states. In the realistic instance, taking into account the
effects of losses and imperfections, we show that as the input two-mode
squeezing increases, optimized non-Gaussian swapping resources allow for a
monotonically increasing enhancement of the fidelity compared to the
corresponding Gaussian setting. This result implies that the use of
non-Gaussian resources is necessary to guarantee the success of
continuous-variable entanglement swapping in the presence of decoherence.


title:
Fine- and hyperfine-structure effects in molecular photoionization: II.
  Resonance-enhanced multiphoton ionization and hyperfine-selective generation
  of molecular cations

abstract:
  Resonance-enhanced multiphoton ionization (REMPI) is a widely used technique
for studying molecular photoionization and producing molecular cations for
spectroscopy and dynamics studies. Here, we present a model for describing
hyperfine-structure effects in the REMPI process and for predicting hyperfine
populations in molecular ions produced by this method. This model is a
generalization of our model for fine- and hyperfine- structure effects in
one-photon ionization of molecules presented in the preceding companion
article. This generalization is achieved by covering two main aspects: (1)
treatment of the neutral bound-bound transition including hyperfine structure
that makes up the first step of the REMPI process and (2) modification of our
ionization model to account for anisotropic populations resulting from this
first excitation step. Our findings may be used for analyzing results from
experiments with molecular ions produced by REMPI and may serve as a
theoretical background for hyperfine-selective ionization experiments.


title: On the survival of zombie vortices in protoplanetary discs

abstract:
  Recently it has been proposed that the zombie vortex instability (ZVI) could
precipitate hydrodynamical activity and angular momentum transport in
unmagnetised regions of protoplanetary discs, also known as "dead zones". In
this letter we scrutinise, with high resolution 3D spectral simulations, the
onset and survival of this instability in the presence of viscous and thermal
physics. First, we find that the ZVI is strongly dependent on the nature of the
viscous operator. Although the ZVI is easily obtained with hyper-diffusion, it
is difficult to sustain with physical (second order) diffusion operators up to
Reynolds numbers as high as 10^7. This sensitivity is probably due to the ZVI's
reliance on critical layers, whose characteristic lengthscale, structure, and
dynamics are controlled by viscous diffusion. Second, we observe that the ZVI
is sensitive to radiative processes, and indeed only operates when the Peclet
number is greater than a critical value ~10^4, or when the cooling time is
longer than ~10 Omega^{-1}. As a consequence, the ZVI struggles to appear at
R>0.3 AU in standard 0.01 M_sun T Tauri disc models, though younger more
massive disks provide a more hospitable environment. Together these results
question the prevalence of the ZVI in protoplanetary discs.


title: The 3-4 $\mu$m Spectra of Jupiter Trojan Asteroids

abstract:
  To date, reflectance spectra of Jupiter Trojan asteroids have revealed no
distinctive absorption features. For this reason, the surface composition of
these objects remains a subject of speculation. Spectra have revealed, however,
that the Jupiter Trojan asteroids consist of two distinct sub-populations which
differ in the optical to near-infrared colors. The origins and compositional
differences between the two sub-populations remain unclear. Here we report the
results from a 2.2-3.8 $\mu$m spectral survey of a collection of 16 Jupiter
Trojan asteroids, divided equally between the two sub-populations. We find
clear spectral absorption features centered around 3.1 $\mu$m in the less red
population. Additional absorption consistent with expected from organic
materials might also be present. No such features are see in the red
population. A strong correlation exists between the strength of the 3.1 $\mu$m
absorption feature and the optical to near-infrared color of the objects. While
traditionally absorptions such as these in dark asteroids are modeled as being
due to fine-grain water frost, we find it physically implausible that the
special circumstances required to create such fine-grained frost would exist on
a substantial fraction of the Jupiter Trojan asteroids. We suggest, instead,
that the 3.1 $\mu$m absorption on Trojans and other dark asteroids could be due
to N-H stretch features. Additionally, we point out that reflectivities derived
from WISE observations show a strong absorption beyond 4$\mu$m for both
populations. The continuum of 3.1 $\mu$m features and the common absorption
beyond 4 $\mu$m might suggest that both sub-populations of Jupiter Trojan
asteroids formed in the same general region of the early solar system.


title: Implicit Tubular Surface Generation Guided by Centerline

abstract:
  Most machine learning-based coronary artery segmentation methods represent
the vascular lumen surface in an implicit way by the centerline and the
associated lumen radii, which makes the subsequent modeling process to generate
a whole piece of watertight coronary artery tree model difficult. To solve this
problem, in this paper, we propose a modeling method with the learning-based
segmentation results by (1) considering mesh vertices as physical particles and
using interaction force model and particle expansion model to generate
uniformly distributed point cloud on the implicit lumen surface and; (2) doing
incremental Delaunay-based triangulation. Our method has the advantage of being
able to consider the complex shape of the coronary artery tree as a whole
piece; hence no extra stitching or intersection removal algorithm is needed to
generate a watertight model. Experiment results demonstrate that our method is
capable of generating high quality mesh model which is highly consistent with
the given implicit vascular lumen surface, with an average error of 0.08 mm.


title: Stellar twins determine the distance of the Pleiades

abstract:
  Since the release of the Hipparcos catalog in 1997, the distance to the
Pleiades open cluster has been heavily debated. The distance obtained from
Hipparcos and those by alternative methods differ by 10 to 15 %. As accurate
stellar distances are key to understanding stellar structure and evolution,
this dilemma puts the validity of stellar evolution models into question. Using
our model-independent method to determine parallaxes based on twin stars, we
report individual parallaxes of 15 FGK type stars in the Pleiades in
anticipation of the astrometric mission Gaia. These parallaxes give a mean
cluster parallax of $7.42\pm0.09~\mathrm{mas}$ corresponding to a mean cluster
distance of ${ 134.8\pm 1.7~\mathrm{pc}}$. This value agrees with the current
results obtained from stellar evolution models.


title: Poisson-Lie T-duals of the bi-Yang-Baxter models

abstract:
  We prove the conjecture of Sfetsos, Siampos and Thompson that suitable
analytic continuations of the Poisson-Lie T-duals of the bi-Yang-Baxter sigma
models coincide with the recently introduced generalized lambda models. We then
generalize this result by showing that the analytic continuation of a generic
sigma model of "universal WZW-type" introduced by Tseytlin in 1993 is nothing
but the Poisson-Lie T-dual of a generic Poisson-Lie symmetric sigma model
introduced by Klimcik and Severa in 1995.


title: Vibrational and optical properties of MoS$_2$: from monolayer to bulk

abstract:
  Molybdenum disulfide, MoS2, has recently gained considerable attention as a
layered material where neighboring layers are only weakly interacting and can
easily slide against each other. Therefore, mechanical exfoliation allows the
fabrication of single and multi-layers and opens the possibility to generate
atomically thin crystals with outstanding properties. In contrast to graphene,
it has an optical gap of 1.9 eV. This makes it a prominent candidate for
transistor and opto-electronic applications. Single-layer MoS$_2$ exhibits
remarkably different physical properties compared to bulk MoS$_2$ due to the
absence of interlayer hybridization. For instance, while the band gap of bulk
and multi-layer MoS$_2$ is indirect, it becomes direct with decreasing number
of layers. In this review, we analyze from a theoretical point of view the
electronic, optical, and vibrational properties of single-layer, few-layer and
bulk MoS$_2$. In particular, we focus on the effects of spin-orbit interaction,
number of layers, and applied tensile strain on the vibrational and optical
properties. We examine the results obtained by different methodologies, mainly
ab initio approaches. We also discuss which approximations are suitable for
MoS$_2$ and layered materials. The effect of external strain on the band gap of
single-layer MoS$_2$ and the crossover from indirect to direct band gap is
investigated. We analyze the excitonic effects on the absorption spectra. The
main features, such as the double peak at the absorption threshold and the
high-energy exciton are presented. Furthermore, we report on the phonon
dispersion relations of single-layer, few-layer and bulk MoS$_2$. Based on the
latter, we explain the behavior of the Raman-active $A_{1g}$ and $E^1_{2g}$
modes as a function of the number of layers.


title: Adjusting inequalities for detection-loophole-free steering experiments

abstract:
  We study the problem of certifying quantum steering in a
detection-loophole-free manner in experimental situations that require
post-selection. We present a method to find the modified local-hidden-state
bound of steering inequalities in such a post-selected scenario. We then
present a construction of linear steering inequalities in arbitrary finite
dimension and show that they certify steering in a loophole-free manner as long
as the detection efficiencies are above the known bound below which steering
can never be demonstrated. We also show how our method extends to the scenarios
of multipartite steering and Bell nonlocality, in the general case where there
can be correlations between the losses of the different parties. In both cases
we present examples to demonstrate the techniques developed.


title:
Bergman iteration and $C^{\infty}$-convergence towards K\"ahler-Ricci
  flow

abstract:
  On a polarized manifold $(X,L)$, the Bergman iteration $\phi_k^{(m)}$ is
defined as a sequence of Bergman metrics on $L$ with two integer parameters $k,
m$. We study the relation between the K\"ahler-Ricci flow $\phi_t$ at any time
$t \geq 0$ and the limiting behavior of metrics $\phi_k^{(m)}$ when $m=m(k)$
and the ratio $m/k$ approaches to $t$ as $k \to \infty$. Mainly, three settings
are investigated: the case when $L$ is a general polarization on a Calabi-Yau
manifold $X$ and the case when $L=\pm K_X$ is the (anti-) canonical bundle.
Recently, Berman showed that the convergence $\phi_k^{(m)} \to \phi_t$ holds in
the $C^0$-topology, in particular, the convergence of curvatures holds in terms
of currents. In this paper, we extend Berman's result and show that this
convergence actually holds in the smooth topology.


title:
Reconstruction and stability for piecewise smooth potentials in the
  plane

abstract:
  We show that potentials with jump discontinuities can be recovered from the
Dirichlet-to-Neumann map using Bukhgeim's method. Combining with known
formulas, this enables the recovery from the scattering amplitude at a fixed
energy. We also provide a priori stability estimates for reconstruction from
the Dirichlet-to-Neumann map as well as from the scattering amplitudegiven an
approximate knowledge of the location of the discontinuities.


title: Feature-based Recursive Observer Design for Homography Estimation

abstract:
  This paper presents a new algorithm for online estimation of a sequence of
homographies applicable to image sequences obtained from robotic vehicles
equipped with vision sensors. The approach taken exploits the underlying
Special Linear group structure of the set of homographies along with gyroscope
measurements and direct point-feature correspondences between images to develop
temporal filter for the homography estimate. Theoretical analysis and
experimental results are provided to demonstrate the robustness of the proposed
algorithm. The experimental results show excellent performance even in the case
of very fast camera motion (relative to frame rate), severe occlusion, and in
the presence of specular reflections.


title: Effect of nematic ordering on electronic structure of FeSe

abstract:
  Electronically driven nematic order is often considered as an essential
ingredient of high-temperature superconductivity. Its elusive nature in
iron-based supercon- ductors resulted in a controversy not only as regards its
origin but also as to the degree of its influence on the electronic structure
even in the simplest representative material FeSe. Here we utilized
angle-resolved photoemission spectroscopy and density functional theory
calculations to study the influence of the nematic order on the electronic
structure of FeSe and determine its exact energy and momentum scales. Our
results strongly suggest that the nematicity in FeSe is electronically driven,
we resolve the recent controversy and provide the necessary quantitative
experimental basis for a successful theory of superconductivity in iron-based
materials which takes into account both, spin-orbit interaction and electronic
nematicity.


title: Note on integrability of certain homogeneous Hamiltonian systems

abstract:
  In this paper we investigate a class of natural Hamiltonian systems with two
degrees of freedom. The kinetic energy depends on coordinates but the system is
homogeneous. Thanks to this property it admits, in a general case, a particular
solution. Using this solution we derive necessary conditions for the
integrability of such systems investigating differential Galois group of
variational equations.


title:
Optical counterparts of two ultraluminous X-ray sources NGC4559 X-10 and
  NGC4395 ULX-1

abstract:
  We study the optical counterparts of ultraluminous X-ray sources NGC4559 X-10
and NGC4395 ULX-1. Their absolute magnitudes, after taking the reddening into
account, are $M_V \approx -5.3$ and $M_V \approx -6.2$, respectively. The
spectral energy distribution of the NGC4559 X-10 counterpart is well fitted by
a spectrum of an F-type star, whereas NGC4395 ULX-1 has a blue power-law
spectrum. Optical spectroscopy of NGC4395 ULX-1 has shown a broad and variable
HeII~$\lambda$4686 emission, which puts this object in line with all the other
spectrally-studied ULXs. Using the Swift archival X-ray data for NGC4395 ULX-1,
we have found a period of $62.8\pm 2.3$ days. The X-ray phase curve of the
source is very similar to the precession curve of SS433. The optical variation
of the counterpart (between two accurate measurements) amounts to 0.10 mag.
Analyzing the absolute magnitudes of 16 well-studied ULX counterparts one may
suggest that as the original accretion rate decreases (but nevertheless remains
supercritical), the optical luminosity of the wind becomes dimmer and the donor
star dominates. However, an observational bias may also influence the
distribution.


title:
Optimal control of elliptic surface PDEs with pointwise bounds on the
  state

abstract:
  We consider a linear-quadratic optimization problem with pointwise bounds on
the state for which the constraint is given by the Laplace-Beltrami equation
(to have uniqueness we add an lower order term) on a two-dimensional surface .
By using finite elements we approximate the optimization problem by a family of
discrete problems and prove convergence rates for the discrete controls and the
discrete states. Furthermore, assuming (roughly spoken) a higher regularity for
the control the order of convergence improves. This extends a result known in
an Euclidean setting to the surface case.


title:
Signal-background interference for a singlet spin-0 digluon resonance at
  the LHC

abstract:
  Dijet mass distributions can be used to search for spin-0 resonances that
couple to two gluons. I show that there is a substantial impact on such
searches from the interference between the resonant signal and the continuum
QCD background amplitudes. The signal dijet mass distribution is qualitatively
modified by this interference, compared to the naive expectation from
considering only the pure resonant contribution, even if the total width of the
resonance is minimal and very small compared to the experimental dijet mass
resolution. The impact becomes more drastic as the total width of the resonance
increases. These considerations are illustrated using examples relevant to the
750 GeV diphoton excess recently observed at the LHC.


title: OptoTracker project proposal

abstract:
  The project OptoTracker aims to investigate a new approach to track charged
particles in a scintillating material, by using the optical signal. Our idea is
to reconstruct the trajectory of a charged particle by collecting the
scintillation light emitted along the path with pixelized photo-detectors. This
would permit to obtain an image of the track, similarly to what is done in a
photographic camera. Full 3D reconstruction is performed by using both the
charge distribution and the hit time information folded in a sophisticated
reconstruction algorithm.
  This solution, compared to "traditional" tracking methods, exploits the
fastest information carrier within a material: the light. Therefore, an optical
tracking detector would be intrinsically capable of sustaining a very high
interaction rate. Moreover, the intrinsic resolution would not be limited by
carriers diffusion, as happens in charge-transport based detectors. This new
technology could have a very large impact both on beam experiments, thanks to
the possible increase in the acquisition rate, and in rare-physics experiments
(double-$\beta$ decay, dark-matter searches, neutrino oscillation searches),
where the enhanced particle-id and directionality capability can provide
significant background reduction.
  This project has been presented to the INFN-Gruppo 5 call for young
scientists in 2014, with positive result. It has been founded for the years
2015-2016.


title:
Extended Ly$\alpha$ emission around quasars with eclipsing damped
  Ly$\alpha$ systems

abstract:
  We present spectroscopic observations of six high redshift ($z_{\rm em}$ $>$
2) quasars, which have been selected for their Lyman $\alpha$ (Ly$\alpha$)
emission region being only partially covered by a strong proximate ($z_{\rm
abs}$ $\sim$ $z_{\rm em}$) coronagraphic damped Ly$\alpha$ system (DLA). We
detected spatially extended Ly$\alpha$ emission envelopes surrounding these six
quasars, with projected spatial extent in the range 26 $\le$ $d_{\rm Ly\alpha}$
$\le$ 51 kpc. No correlation is found between the quasar ionizing luminosity
and the Ly$\alpha$ luminosity of their extended envelopes. This could be
related to the limited covering factor of the extended gas and/or due to the
AGN being obscured in other directions than towards the observer. Indeed, we
find a strong correlation between the luminosity of the envelope and its
spatial extent, which suggests that the envelopes are probably ionized by the
AGN. The metallicity of the coronagraphic DLAs is low and varies in the range
$-$1.75 $<$ [Si/H] $<$ $-$0.63. Highly ionized gas is observed to be associated
with most of these DLAs, probably indicating ionization by the central AGN. One
of these DLAs has the highest AlIII/SiII ratio ever reported for any
intervening and/or proximate DLA. Most of these DLAs are redshifted with
respect to the quasar, implying that they might represent infalling gas
probably accreted onto the quasar host galaxies through filaments.


title: Extreme Value Laws for dynamical systems with countable extremal sets

abstract:
  We consider stationary stochastic processes arising from dynamical systems by
evaluating a given observable along the orbits of the system. We focus on the
extremal behaviour of the process, which is related to the entrance in certain
regions of the phase space, which correspond to neighbourhoods of the maximal
set $\mathcal M$, i.e. the set of points where the observable is maximised. The
main novelty here is the fact that we consider that the set $\mathcal M$ may
have a countable number of points, which are associated by belonging to the
orbit of a certain point, and may have accumulation points. In order to prove
the existence of distributional limits and study the intensity of clustering,
given by the Extremal Index, we generalise the conditions previously introduced
in \cite{FFT12,FFT15}.


title:
Analytical investigation of the decrease in the size of the habitable
  zone due to limited CO$_2$ outgassing rate

abstract:
  The habitable zone concept is important because it focuses the scientific
search for extraterrestrial life and aids the planning of future telescopes.
Recent work has shown that planets near the outer edge of the habitable zone
might not actually be able to stay warm and habitable if CO$_2$ outgassing
rates are not large enough to maintain high CO$_2$ partial pressures against
removal by silicate weathering. In this paper I use simple equations for the
climate and CO$_2$ budget of a planet in the habitable zone that can capture
the qualitative behavior of the system. With these equations I derive an
analytical formula for an effective outer edge of the habitable zone, including
limitations imposed by the CO$_2$ outgassing rate. I then show that climate
cycles between a Snowball state and a warm climate are only possible beyond
this limit if the weathering rate in the Snowball climate is smaller than the
CO$_2$ outgassing rate (otherwise stable Snowball states result). I derive an
analytical solution for the climate cycles including a formula for their period
in this limit. This work allows us to explore the qualitative effects of
weathering processes on the effective outer edge of the habitable zone, which
is important because weathering parameterizations are uncertain.


title:
A Study of the B/C Ratio Between 10 MeV/nuc and 1 TeV/nuc in Cosmic Rays
  Using New Voyager and AMS-2 Data and a Comparison with the Predictions of
  Leaky Box Propagation Models

abstract:
  This paper seeks to find an explanation of the galactic cosmic ray B/C ratio
newly measured in cosmic rays between ~10 MeV/nuc and 1 TeV/nuc. Voyager
measurements of this ratio at low energies and AMS-2 measurements at high
energies are used in this study. These measurements both considerably exceed at
both low and high energies the ratio predicted using a simple Leaky Box Model
for propagation of cosmic rays in the galaxy. Between 1-70 GeV/nuc, however,
this same model provides an excellent fit (within +2-3%) to the new AMS-2
measurements using an escape length ~P-0.45. This would imply a diffusion
coefficient ~P0.45, very close to the Kraichian cascade value of 0.50 for the
exponent. Extending this same diffusion dependence to high energies, still in a
LBM, along with a truncation of short path lengths in the galaxy will predict a
B/C ratio of 4.5% at ~800 GeV/nuc which is very close to the AMS-2 measurement
at that energy. This would indicate that the amount of material traversed near
the source in a Nested LBM, for example, is less than about 0.5 g/cm2 at these
energies since this process, with additional matter near the sources, would
increase the B/C ratio. At low energies, however, the B/C ratio of 14% +3% at
~10 MeV/nuc measured by Voyager is more difficult to explain. The same
parameters used in a LBM that fit the high energy B/C measurements predicts a
B/C ratio of only ~4% at 10 MeV/nuc where the path length is about 1.5 g/cm2.
If the cosmic rays have traversed ~10 g/cm2 of material in the galaxy at low
energies the prediction for B/C is still only 8%, which is between 2.0-3.0
sigma below the measurement and its errors.


title:
A strategy to implement Dirichlet boundary conditions in the context of
  ADER finite volume schemes. One-dimensional conservation laws

abstract:
  ADER schemes are numerical methods, which can reach an arbitrary order of
accuracy in both space and time. They are based on a reconstruction procedure
and the solution of generalized Riemann problems. However, for general boundary
conditions, in particular of Dirichlet type, a lack of accuracy might occur if
a suitable treatment of boundaries conditions is not properly carried out. In
this work the treatment of Dirichlet boundary conditions for conservation laws
in the context of ADER schemes, is concerned. The solution of generalized
Riemann problems at the extremes of the computational domain, provides the
correct influence of boundaries. The reconstruction procedure, for data near to
the boundaries, demands for information outside the computational domain, which
is carried out in terms of ghost cells, which are provided by using the
numerical solution of auxiliary problems. These auxiliary problems are
hyperbolic and they are constructed from the conservation laws and the
information at boundaries, which may be partially or totally known in terms of
prescribed functions. The evolution of these problems, unlike to the usual
manner, is done in space rather than in time due to that these problems are
named here, {\it reverse problems}. The methodology can be considered as a
numerical counterpart of the inverse Lax-Wendroff procedure for filling ghost
cells. However, the use of Taylor series expansions, as well as, Lax-Wendroff
procedure, are avoided. For the scalar case is shown that the present procedure
preserve the accuracy of the scheme which is reinforced with some numerical
results. Expected orders of accuracy for solving conservation laws by using the
proposed strategy at boundaries, are obtained up to fifth-order in both space
and time.


title:
Survival trees for left-truncated and right-censored data, with
  application to time-varying covariate data

abstract:
  Tree methods (recursive partitioning) are a popular class of nonparametric
methods for analyzing data. One extension of the basic tree methodology is the
survival tree, which applies recursive partitioning to censored survival data.
There are several existing survival tree methods in the literature, which are
mainly designed for right-censored data. We propose two new survival trees for
left-truncated and right-censored (LTRC) data, which can be seen as a
generalization of the traditional survival tree for right-censored data.
Further, we show that such trees can be used to analyze survival data with
time-varying covariates, essentially building a time-varying covariates
survival tree. Implementation of the methods is easy, and simulations and real
data analysis results show that the proposed methods work well for LTRC data
and survival data with time-varying covariates, respectively.


title: Sutured annular Khovanov homology and two periodic braids

abstract:
  Let $\widetilde{K}$ be a two-periodic braid and let $K$ be its quotient. In
this paper we show there is a spectral sequence from the next-to-top winding
number grading of the sutured annular Khovanov homology of the closure of
$\widetilde{K}$ to the next-to-top winding number grading of the sutured
annular Khovanov homology of the closure of $K$.


title: Tidal deformability of boson stars and dark matter clumps

abstract:
  In this work we consider minimally-coupled boson stars immersed in a tidal
environment and compute their tidal deformability to leading order. We also
describe an approximate correspondence between Newtonian boson star
configurations (described by the Schr\"{o}dinger-Poisson equations) and
dynamical dark matter clumps (described by the collisionless Boltzmann
equation). This allows us to map our results for the tidal deformability of
boson stars to approximate statements for dark matter clumps.


title:
Symmetry enhancements via 5d instantons, qW-algebrae and (1,0)
  superconformal index

abstract:
  We explore N=(1,0) superconformal six-dimensional theories arising from
M5-branes probing a transverse A_k singularity. Upon circle compactification to
5 dimensions, we describe this system with a dual pq-web of five-branes and
propose the spectrum of basic five-dimensional instanton operators driving
global symmetry enhancement. For a single M5-brane, we find that the exact
partition function of the 5d quiver gauge theory matches the 6d (1,0) index,
which we compute by letter counting. We finally show that S-duality of the
pq-web implies new relations among vertex correlators of qW-algebrae.


title:
A New Challenge to Solar Dynamo Models from Helioseismic Observations:
  The Latitudinal Dependence of the Progression of the Solar Cycle

abstract:
  The solar cycle onset at mid-latitudes, the slow down of the sunspot drift
toward the equator, the tail-like attachment and the overlap of successive
cycles at the time of activity minimum are delicate issues in $\alpha\Omega$
dynamo wave and flux transport dynamo models. Very different parameter values
produce similar results, making it difficult to understand the origin of these
solar cycle properties. We use GONG helioseismic data to investigate the
progression of the solar cycle as observed in intermediate-degree global
$p$-mode frequency shifts at different latitudes and subsurface layers, from
the beginning of solar cycle 23 up to the maximum of the current solar cycle.
We also analyze those for high-degree modes in each hemisphere obtained through
the ring-diagram technique of local helioseismology. The analysis highlighted
differences in the progression of the cycle below 15\degr\ compared to higher
latitudes. While the cycle starts at mid-latitudes and then migrates
equatorward/poleward, the sunspot eruptions of the old cycle are still ongoing
below 15\degr\ latitude. This prolonged activity causes a delay in the cycle
onset and an overlap of successive cycles, whose extension differs in the two
hemispheres. Then the activity level rises faster reaching a maximum
characterized by a single peak structure compared to the double peak at higher
latitudes. Afterwards the descending phase shows up with a slower decay rate.
The latitudinal properties of the solar cycle progression highlighted in this
study provide useful constraints to discern among the multitude of solar dynamo
models.


title:
Landau Levels in 2D materials using Wannier Hamiltonians obtained by
  first principles

abstract:
  We present a method to calculate the Landau levels and the corresponding edge
states of two dimensional (2D) crystals using as a starting point their
electronic structure as obtained from standard density functional theory (DFT).
The DFT Hamiltonian is represented in the basis of maximally localized Wannier
functions. This defines a tight-binding Hamiltonian for the bulk that can be
used to describe other structures, such as ribbons, provided that atomic scale
details of the edges are ignored. The effect of the orbital magnetic field is
described using the Peierls substitution in the hopping matrix elements.
Implementing this approach in a ribbon geometry, we obtain both the Landau
levels and the dispersive edge states for a series of 2D crystals, including
graphene, Boron Nitride, MoS$_2$ , Black Phosphorous, Indium Selenide and
MoO$_3$ . Our procedure can readily be used in any other 2D crystal, and
provides an alternative to effective mass descriptions.


title:
Numerical validation of blow-up solutions of ordinary differential
  equations

abstract:
  This paper focuses on blow-up solutions of ordinary differential equations
(ODEs). We present a method for validating blow-up solutions and their blow-up
times, which is based on compactifications and the Lyapunov function validation
method. The necessary criteria for this construction can be verified using
interval arithmetic techniques. Some numerical examples are presented to
demonstrate the applicability of our method.


title:
Structural and magnetic characterization of the one-dimensional S = 5/2
  antiferromagnetic chain system SrMn(VO4)(OH)

abstract:
  The descloizite-type compound, SrMn(VO4)(OH), was synthesized as large single
crystals using a high-temperature high-pressure hydrothermal technique. X-ray
single crystal structure analysis reveals that the material crystallizes in the
acentric orthorhombic space group of P212121. The structure exhibits a
one-dimensional feature, with MnO4 chains propagating along the a-axis which
are interconnected by VO4 tetrahedra. Raman and infrared spectra were obtained
to identify the fundamental vanadate and hydroxide vibrational modes.
Magnetization data reveal a broad maximum at approximately 80 K, arising from
one-dimensional magnetic correlations with intrachain exchange constant of J/kB
= 9.97(3) K between nearest Mn neighbors and a canted antiferromagnetic
behavior below TN = 30 K. Single crystal neutron diffraction at 4 K yielded a
magnetic structure solution in the lower symmetry of the magnetic space group
P21 with two unique chains displaying antiferromagnetically ordered Mn moments
oriented nearly perpendicular to the chain axis. The presence of the
Dzyaloshinskii Moriya antisymmetric exchange interaction leads to a slight
canting of the spins and gives rise to a weak ferromagnetic component along the
chain direction.


title: Dynamics and stability of surfactant-driven surface waves

abstract:
  In this paper we consider a layer of incompressible viscous fluid lying above
a flat periodic surface in a uniform gravitational field. The upper boundary of
the fluid is free and evolves in time. We assume that a mass of surfactants
resides on the free surface and evolves in time with the fluid. The surfactants
dynamics couple to the fluid dynamics by adjusting the surface tension
coefficient on the interface and also through tangential Marangoni stresses
caused by gradients in surfactant concentration. We prove that small
perturbations of equilibria give rise to global-in-time solutions in an
appropriate functional space, and we prove that the solutions return to
equilibrium exponentially fast. In particular this proves the asymptotic
stability of equilibria.


title:
Parametrizations of the $\gamma^\ast N \to \Delta(1232)$ quadrupole form
  factors and Siegert's theorem

abstract:
  The large $N_c$ limit provides relations that can be used to calculate the
$\gamma^\ast N \to \Delta(1232)$ quadrupole form factors at low and
intermediate $Q^2$ under the assumption of the pion cloud dominance. There are
two limitations in those parametrizations. First, the parametrization of the
Coulomb quadrupole form factor underestimate the low $Q^2$ data. Second, when
extrapolated for the timelike region, the form factors violate Siegert's
theorem by terms of the order $1/N_c^2$. We propose here corrections to the
parametrization of the electric quadrupole form factor, which violate Siegert's
theorem only by terms of the order $1/N_c^4$. Combining the improved large
$N_c$ pion cloud parametrizations with the valence quark contributions based on
a covariant quark model for the quadrupole transition form factors, we obtain
an extrapolation to the timelike region consistent with Siegert's theorem, and
accomplish also a very good description of the data.


title:
Evidence for a dual population of neutron star mergers from short
  Gamma-Ray Burst observations

abstract:
  Short duration Gamma-Ray Bursts are thought to originate from the coalescence
of neutron stars in binary systems. They are detected as a brief ($<$ 2s),
intense flash of gamma-ray radiation followed by a weaker, rapidly decreasing
afterglow. They are expected to be detected by Advanced LIGO and Virgo when
their sensitivity will be low enough. In a recent study we identified a
population of short Gamma-Ray Bursts that are intrinsically faint and nearby.
Here we provide evidence in favor of the existence of this new population that
can hardly be reproduced with a model of field neutron star binary
coalescences. We propose that these systems may be produced dynamically in
globular clusters, and may result from the merger of a black hole and a neutron
star. The advanced LIGO and Virgo observation of a high rate of NSBH mergers
compatible with the dynamical formation in globular clusters would be a
confirmation of this hypothesis and would enable for the derivation of the mass
function of black holes inside globular clusters, as well as the luminosity
function of faint short GRBs.