title:
Magnetic anisotropic energy gap and low energy spin wave excitation in
  antiferromagnetic block phase of K2Fe4Se5

abstract:
  Neutron scattering experiments were performed to investigate magnetic order
and magnetic excitations in ternary iron chalcogenide K2Fe4Se5. The formation
of a superlattice structure below 580 K together with the decoupling between
the Fe-vacancy order-disorder transition and the antiferromagnetic order
transition appears to be a common feature in the A2Fe4Se5 family. The study of
spin dynamics of K2Fe4Se5 reveals two distinct energy gaps at the magnetic
Brillouin zone center, which indicates the presence of magnetic anisotropy and
the decrease of local symmetry due to electronic and orbital anisotropy. The
low-energy spin wave excitations of K2Fe4Se5 can be properly described by
linear spin wave theory within a Heisenberg model. Compared to iron pnictides,
K2Fe4Se5 exhibits a more two-dimensional magnetism as characterized by large
differences not only between out-of-plane and in-plane spin wave velocities,
but also between out-of-plane and in-plane exchange interactions.


title: The Regularity Lemma with bounded VC Dimension

abstract:
  We give a proof of Szemeredi's regularity lemma in the special case of a
graph with bounded VC dimension and show that it is possible to obtain "merely"
doubly exponential bounds on the size of the partition in this case.


title: Methods to study splicing from high-throughput RNA Sequencing data

abstract:
  The development of novel high-throughput sequencing (HTS) methods for RNA
(RNA-Seq) has provided a very powerful mean to study splicing under multiple
conditions at unprecedented depth. However, the complexity of the information
to be analyzed has turned this into a challenging task. In the last few years,
a plethora of tools have been developed, allowing researchers to process
RNA-Seq data to study the expression of isoforms and splicing events, and their
relative changes under different conditions. We provide an overview of the
methods available to study splicing from short RNA-Seq data. We group the
methods according to the different questions they address: 1) Assignment of the
sequencing reads to their likely gene of origin. This is addressed by methods
that map reads to the genome and/or to the available gene annotations. 2)
Recovering the sequence of splicing events and isoforms. This is addressed by
transcript reconstruction and de novo assembly methods. 3) Quantification of
events and isoforms. Either after reconstructing transcripts or using an
annotation, many methods estimate the expression level or the relative usage of
isoforms and/or events. 4) Providing an isoform or event view of differential
splicing or expression. These include methods that compare relative
event/isoform abundance or isoform expression across two or more conditions. 5)
Visualizing splicing regulation. Various tools facilitate the visualization of
the RNA-Seq data in the context of alternative splicing. In this review, we do
not describe the specific mathematical models behind each method. Our aim is
rather to provide an overview that could serve as an entry point for users who
need to decide on a suitable tool for a specific analysis. We also attempt to
propose a classification of the tools according to the operations they do, to
facilitate the comparison and choice of methods.


title:
One-dimensional transport of interacting particles: Currents, density
  profiles, phase diagrams and symmetries

abstract:
  Driven lattice gases serve as canonical models for investigating collective
transport phenomena and properties of non-equilibrium steady states (NESS).
Here we study one-dimensional transport with nearest-neighbor interactions both
in closed bulk systems and in open channels coupled to two particle reservoirs
at the ends of the channel. For the widely employed Glauber rates we derive an
exact current-density relation in the bulk for unidirectional hopping. An
approach based on time-dependent density functional theory provides a good
description of the kinetics. For open systems, the system-reservoir couplings
are shown to have a striking influence on boundary-induced phase diagrams. The
role of particle-hole symmetry is discussed and its consequence on the topology
of the phase diagrams. It is furthermore demonstrated that systems with weak
bias can be mapped onto systems with unidirectional hopping.


title: Coherence and strictification for self-similarity

abstract:
  This paper studies questions of coherence and strictification related to
self-similarity - the identity $S\cong S\otimes S$ in a (semi-)monoidal
category. Based on Saavedra's theory of units, we first demonstrate that strict
self-similarity cannot simultaneously occur with strict associativity -- i.e.
no monoid may have a strictly associative (semi-)monoidal tensor, although many
monoids have a semi-monoidal tensor associative up to isomorphism. We then give
a simple coherence result for the arrows exhibiting self-similarity and use
this to describe a `strictification procedure' that gives a semi-monoidal
equivalence of categories relating strict and non-strict self-similarity, and
hence monoid analogues of many categorical properties. Using this, we
characterise a large class of diagrams (built from the canonical isomorphisms
for the relevant tensors, together with the isomorphisms exhibiting the
self-similarity) that are guaranteed to commute.


title:
Self-compression to sub-3-cycle duration of mid-infrared optical pulses
  in bulk

abstract:
  The generation of few-cycle pulses with controlled waveforms in the
mid-infrared spectral region is a long-standing challenge but is expected to
enable a new generation of high-field physics experiments, uncovering intricate
physical phenomena. Successful generation of such optical pulses is limited by
the tremendous spectral width required to withstand few-cycle pulses in the
mid-IR correlated with the need to tightly control the spectral phase over such
a broad bandwidth. Here, we present the first demonstration of sub-three cycle
optical pulses at 3.1 \mu m central wavelength using for the first time
self-compression in the anomalous dispersion regime in bulk material. The
pulses emerging from this compact and efficient self-compression setup could be
focused to intensities exceeding 100 TW/cm^2, a suitable range for high field
physics experiments. Our experimental findings are corroborated by numerical
simulations using a 3D nonlinear propagation code, therefore providing
theoretical insight on the processes involved.


title: Survival of the Scarcer in Space

abstract:
  The dynamics leading to extinction or coexistence of competing species is of
great interest in ecology and related fields. Recently a model of intra- and
interspecific competition between two species was proposed by Gabel et al.
[Phys. Rev. E 87 (2013) 010101], in which the scarcer species (i.e., with
smaller stationary population size) can be more resistant to extinction when it
holds a competitive advantage; the latter study considered populations without
spatial variation. Here we verify this phenomenon in populations distributed in
space. We extend the model of Gabel et al. to a d-dimensional lattice, and
study its population dynamics both analytically and numerically. Survival of
the scarcer in space is verified for situations in which the more competitive
species is closer to the threshold for extinction than is the less competitive
species, when considered in isolation. The conditions for survival of the
scarcer species, as obtained applying renormalization group analysis and Monte
Carlo simulation, differ in detail from those found in the spatially
homogeneous case. Simulations highlight the speed of invasion waves in
determining the survival times of the competing species.


title:
Further matters in space-time geometry: $f(R,T,R_{\mu\nu}T^{\mu\nu})$
  gravity

abstract:
  We consider a gravitational model in which matter is non-minimally coupled to
geometry, with the effective Lagrangian of the gravitational field being given
by an arbitrary function of the Ricci scalar, the trace of the matter
energy-momentum tensor, and the contraction of the Ricci tensor with the matter
energy-momentum tensor. The field equations of the model are obtained in the
metric formalism, and the equation of motion of a massive test particle is
derived. In this type of models the matter energy-momentum tensor is generally
not conserved, and this non-conservation determines the appearance of an
extra-force acting on the particles in motion in the gravitational field. The
Newtonian limit of the model is also considered, and an explicit expression for
the extra-acceleration which depends on the matter density is obtained in the
small velocity limit for dust particles. We also analyze in detail the
so-called Dolgov-Kawasaki instability, and obtain the stability conditions of
the model with respect to local perturbations. A particular class of
gravitational field equations can be obtained by imposing the conservation of
the energy-momentum tensor. We derive the corresponding field equations for the
conservative case by using a Lagrange multiplier method, from a gravitational
action that explicitly contains an independent parameter multiplying the
divergence of the energy-momentum tensor. The cosmological implications of the
model are investigated for both the conservative and non-conservative cases,
and several classes of analytical solutions are obtained.


title: Characterizations of Dirichlet-type Spaces

abstract:
  We give three characterizations of the Dirichlet-type spaces $D(\mu)$. First
we characterize $D(\mu)$ in terms of a double integral and in terms of the mean
oscillation in the Bergman metric, none of them involve the use of derivatives.
Next, we obtain another characterization for $D(\mu)$ in terms of higher order
derivatives. Also, a decomposition theorem for $D(\mu)$ is established.


title: Entanglement spectrum and entangled modes of random XX spin chains

abstract:
  We study in this work the ground state entanglement properties of finite XX
spin-1/2 chains with random couplings, using Jordan-Wigner transformation. We
divide the system into two parts and study reduced density matrices (RDMs) of
its subsystems. Due to the free-fermion nature of the problem, the RDMs take
the form of that of a free fermion thermal ensemble. Finding spectrum of the
corresponding entanglement Hamiltonian and corresponding eigenvectors, and
comparing them with real space renormalization group (RSRG) treatment, we
establish the validity of the RSRG approach for entanglement in the limit of
strong disorder, but also find its limitations when disorder is weak. In the
latter case our work provides a way to visualize the "effective spins" that
form long distance singlet pairs.


title:
Dissipative Quantum Transport in Macromolecules: An Effective Field
  Theory Approach

abstract:
  We introduce an atomistic approach to the dissipative quantum dynamics of
charged or neutral excitations propagating through macromolecular systems.
Using the Feynman-Vernon path integral formalism, we analytically trace out
from the density matrix the atomic coordinates and the heat bath degrees of
freedom. This way we obtain an effective field theory which describes the
real-time evolution of the quantum excitation and is fully consistent with the
fluctuation-dissipation relation. The main advantage of the field-theoretic
approach is that it allows to avoid using the Keldysh contour formulation. This
simplification makes it straightforward to derive Feynman diagrams to
analytically compute the effects of the interaction of the propagating quantum
excitation with the heat bath and with the molecular atomic vibrations. For
illustration purposes, we apply this formalism to investigate the loss of
quantum coherence of holes propagating through a poly(3-alkylthiophene) polymer

categories: cond-mat.soft cond-mat.str-el physics.bio-ph q-bio.BM


title: Backdoors to Abduction

abstract:
  Abductive reasoning (or Abduction, for short) is among the most fundamental
AI reasoning methods, with a broad range of applications, including fault
diagnosis, belief revision, and automated planning. Unfortunately, Abduction is
of high computational complexity; even propositional Abduction is
\Sigma_2^P-complete and thus harder than NP and coNP. This complexity barrier
rules out the existence of a polynomial transformation to propositional
satisfiability (SAT). In this work we use structural properties of the
Abduction instance to break this complexity barrier. We utilize the problem
structure in terms of small backdoor sets. We present fixed-parameter tractable
transformations from Abduction to SAT, which make the power of today's SAT
solvers available to Abduction.


title: The pricing formula for cancellable European options

abstract:
  This paper examines the value of a cancellable European option in a finite
time horizon setting. The specifications of this generalized European option
allow the seller to cancel the option at any point in time for a fixed penalty
paid directly to the holder. Here, we provide an explicit valuation formula for
the European game call where the early cancellation time is obtained
iteratively.


title:
Hawking radiation of scalars from charged accelerating and rotating
  black holes with NUT parameter

abstract:
  We study the quantum tunneling of scalars from charged accelerating and
rotating black hole with NUT parameter. For this purpose we use the charged
Klein-Gordon equation. We apply WKB approximation and the Hamilton-Jacobi
method to solve charged the Klein-Gordon equation. We find the tunneling
probability of outgoing charged scalars from the event horizon of this black
hole, and hence the Hawking temperature for this black hole.


title: A challenge to 3-manifold topologists and group algebraists

abstract:
  This paper poses some basic questions about instances (hard to find) of a
special problem in 3-manifold topology. "Important though the general concepts
and propositions may be with the modern industrious passion for axiomatizing
and generalizing has presented us...nevertheless I am convinced that the
special problems in all their complexity constitute the stock and the core of
mathematics; and to master their difficulty requires on the whole the harder
labor." Hermann Weyl 1885-1955, cited in the preface of the first edition
(1939) of \cite{whitehead1997}.


title: Footprints in the wind of Vela X-1 traced with MAXI

abstract:
  The stellar wind around the compact object in luminous wind-accreting high
mass X-ray binaries is expected to be strongly ionized with the X-rays coming
from the compact object. The stellar wind of hot stars is mostly driven by
light absorption in lines of heavier elements, and X-ray photo-ionization
significantly reduces the radiative force within the so-called Stroemgren
region leading to wind stagnation around the compact object. In close binaries
like Vela X-1 this effect might alter the wind structure throughout the system.
Using the spectral data from Monitor of All-sky X-ray Image (MAXI), we study
the observed dependence of the photoelectric absorption as function of orbital
phase in Vela X-1, and find that it is inconsistent with expectations for a
spherically-symmetric smooth wind. Taking into account previous investigations
we develop a simple model for wind structure with a stream-like photoionization
wake region of slower and denser wind trailing the neutron star responsible for
the observed absorption curve.


title: SW# - GPU enabled exact alignments on genome scale

abstract:
  Sequence alignment is one of the oldest and the most famous problems in
bioinformatics. Even after 45 years, for one reason or another, this problem is
still actual; current solutions are trade-offs between execution time, memory
consumption and accuracy. We purpose SW#, a new CUDA GPU enabled and memory
efficient implementation of dynamic programming algorithms for local alignment.
In this implementation indels are treated using the affine gap model. Although
there are other GPU implementations of the Smith-Waterman algorithm, SW# is the
only publicly available implementation that can produce sequence alignments on
genome-wide scale. For long sequences, our implementation is at least a few
hundred times faster than a CPU version of the same algorithm.


title:
Bayesian Nonparametric Estimation of Milky Way Model Parameters Using a
  New Matrix-Variate Gaussian Process Based Method

abstract:
  In this paper we develop an inverse Bayesian approach to find the value of
the unknown model parameter vector that supports the real (or test) data, where
the data comprises measurements of a matrix-variate variable. The method is
illustrated via the estimation of the unknown Milky Way feature parameter
vector, using available test and simulated (training) stellar velocity data
matrices. The data is represented as an unknown function of the model
parameters, where this high-dimensional function is modelled using a
high-dimensional Gaussian Process (${\cal GP}$). The model for this function is
trained using available training data and inverted by Bayesian means, to
estimate the sought value of the model parameter vector at which the test data
is realised. We achieve a closed-form expression for the posterior of the
unknown parameter vector and the parameters of the invoked ${\cal GP}$, given
test and training data. We perform model fitting by comparing the observed data
with predictions made at different summaries of the posterior probability of
the model parameter vector. As a supplement, we undertake a leave-one-out cross
validation of our method.


title: Multifractal zero mode for disordered graphene

abstract:
  Off-diagonal disorder with random hopping between the sublattices of a
bipartite lattice is described by a Hamiltonian which has chiral (sub-lattice)
symmetry. The energy spectrum is symmetric around E=0 and for odd total number
of lattice sites an isolated zero mode always exists, which coincides with the
mobility edge of an Anderson transition in two dimensions(2D). In the chiral
orthogonal symmetry class BDI we compute the fractal dimension $D_{2}$ of the
zero mode for graphene samples with edges. In the absence of disorder
$D_{2}=1$, which corresponds to a one-dimensional edge states, while for strong
disorder $D_{2}$ decays towards 0 and the zero mode becomes localized. The
similarities and differences between zero modes in the honeycomb and the square
bipartite lattices are pointed out.


title: The quantum plasma lens concept: a preliminary investigation

abstract:
  Recently, a theoretical investigation of the collective and nonlocal quantum
effects has been carried out within the framework of a quantum approach to the
relativistic charged particle beam travelling in a cold, collisionless,
strongly magnetized plasma. This has been done taking into account both the
plasma wake field excitation and the quantum paraxial approximation. On the
basis of this theory, here we carry out a preliminary study of the transverse
effects experienced by a cold relativistic beam through a thin plasma slab
(plasma lens). In the strongly nonlocal regime, in which the beam experiences a
very strong focusing effect, the scheme of plasma lens is reviewed in terms of
the wave description provided by the above quantum theory.


title: Three Generalizations of the FOCUS Constraint

abstract:
  The FOCUS constraint expresses the notion that solutions are concentrated. In
practice, this constraint suffers from the rigidity of its semantics. To tackle
this issue, we propose three generalizations of the FOCUS constraint. We
provide for each one a complete filtering algorithm as well as discussing
decompositions.


title: A Competitive Strategy for Distance-Aware Online Shape Allocation

abstract:
  We consider the following online allocation problem: Given a unit square S,
and a sequence of numbers n_i between 0 and 1, with partial sum bounded by 1;
at each step i, select a region C_i of previously unassigned area n_i in S. The
objective is to make these regions compact in a distance-aware sense: minimize
the maximum (normalized) average Manhattan distance between points from the
same set C_i. Related location problems have received a considerable amount of
attention; in particular, the problem of determining the "optimal shape of a
city", i.e., allocating a single n_i has been studied. We present an online
strategy, based on an analysis of space-filling curves; for continuous shapes,
we prove a factor of 1.8092, and 1.7848 for discrete point sets.


title: Thermomechanical properties of a single hexagonal boron nitride sheet

abstract:
  Using atomistic simulations we investigate the thermodynamical properties of
a single atomic layer of hexagonal boron nitride (h-BN). The thermal induced
ripples, heat capacity, and thermal lattice expansion of large scale h-BN
sheets are determined and compared to those found for graphene (GE) for
temperatures up to 1000 K. By analyzing the mean square height fluctuations $<
h^2>$ and the height-height correlation function $H(q)$ we found that the h-BN
sheet is a less stiff material as compared to graphene. The bending rigidity of
h-BN: i) is about 16% smaller than the one of GE at room temperature (300 K),
and ii) increases with temperature as in GE. The difference in stiffness
between h-BN and GE results in unequal responses to external uniaxial and shear
stress and different buckling transitions. In contrast to a GE sheet, the
buckling transition of a h-BN sheet depends strongly on the direction of the
applied compression. The molar heat capacity, thermal expansion coefficient and
the Gruneisen parameter are estimated to be 25.2 J\,mol$^{-1}$\,K$^{-1}$,
7.2$\times10^{-6}$K$^{-1}$ and 0.89, respectively.


title: Separating Hierarchical and General Hub Labelings

abstract:
  In the context of distance oracles, a labeling algorithm computes vertex
labels during preprocessing. An $s,t$ query computes the corresponding distance
from the labels of $s$ and $t$ only, without looking at the input graph. Hub
labels is a class of labels that has been extensively studied. Performance of
the hub label query depends on the label size. Hierarchical labels are a
natural special kind of hub labels. These labels are related to other problems
and can be computed more efficiently. This brings up a natural question of the
quality of hierarchical labels. We show that there is a gap: optimal
hierarchical labels can be polynomially bigger than the general hub labels. To
prove this result, we give tight upper and lower bounds on the size of
hierarchical and general labels for hypercubes.


title:
Dynamic stochastic blockmodels: Statistical models for time-evolving
  networks

abstract:
  Significant efforts have gone into the development of statistical models for
analyzing data in the form of networks, such as social networks. Most existing
work has focused on modeling static networks, which represent either a single
time snapshot or an aggregate view over time. There has been recent interest in
statistical modeling of dynamic networks, which are observed at multiple points
in time and offer a richer representation of many complex phenomena. In this
paper, we propose a state-space model for dynamic networks that extends the
well-known stochastic blockmodel for static networks to the dynamic setting. We
then propose a procedure to fit the model using a modification of the extended
Kalman filter augmented with a local search. We apply the procedure to analyze
a dynamic social network of email communication.


title:
Some Hadamard and Simpson type integral inequalities via s-convexity and
  their applications

abstract:
  In this study, we establish and generalize some inequalities of Hadamard and
Simpson type based on s-convexity in the second sense. Some applications to
special means of positive real numbers are also given and generalized. Examples
are given to show the results. The results generalize the integral inequalities
in [11] and [13].


title:
Electronic Structure Modeling of Electrochemical Reactions at
  Electrode/Electrolyte Interfaces in Lithium Ion Batteries

abstract:
  We review recent ab initio molecular dynamics studies of
electrode/electrolyte interfaces in lithium ion batteries. Our goals are to
introduce experimentalists to simulation techniques applicable to models which
are arguably most faithful to experimental conditions so far, and to emphasize
to theorists that the inherently interdisciplinary nature of this subject
requires bridging the gap between solid and liquid state perspectives. We
consider liquid ethylene carbonate (EC) decomposition on lithium intercalated
graphite, lithium metal, oxide-coated graphite, and spinel manganese oxide
surfaces. These calculations are put in the context of more widely studied
water-solid interfaces. Our main themes include kinetically controlled
two-electron-induced reactions, the breaking of a previously much neglected
chemical bond in EC, and electron tunneling. Future work on modeling batteries
at atomic lengthscales requires capabilities beyond state-of-the-art, which
emphasizes that applied battery research can and should drive fundamental
science development.


title: A general framework for phase and interference

abstract:
  Phase plays a crucial role in many quantum effects including interference.
Phase is normally defined in terms of complex numbers that appear when
representing quantum states as complex vectors. Here we give an operational
definition whereby phase is instead defined in terms of measurement statistics.
Our definition is phrased in terms of the operational framework known as
generalised probabilistic theories, or the convex framework. The definition
makes it possible to ask whether other theories in this framework can also have
phase. We apply our definition to investigate phase and interference in several
example theories: classical probability theory, a version of Spekken's toy
model, quantum theory, and box-world. We find that phase is ubiquitous; any
non-classical theory can be said to have non-trivial phase dynamics.


title:
Vortex dynamics and second magnetization peak in
  PrFeAsO$_{0.60}$F$_{0.12}$ superconductor

abstract:
  We have studied the vortex dynamics in the PrFeAsO$_{0.60}$F$_{0.12}$
superconducting sample by dc magnetization and dynamic magnetization-relaxation
rate $(Q)$ measurements. The field dependence of the superconducting
irreversible magnetization $M_s$ reveals a second magnetization peak or
fishtail effect. The large value of $Q$ is an indication of moderate vortex
motion and relatively weak pinning energy. Data analysis based on the
generalized inversion scheme suggests that the vortex dynamics can be described
by the collective pinning model. The temperature dependence of the critical
current is consistent with the pinning due to the spatial variation in the mean
free path near a lattice defect ($\delta l$ pinning). The temperature and field
dependence of $Q$ indicates a crossover from elastic to plastic vortex creep
with increasing temperature and magnetic field. Finally, we have constructed
the vortex phase diagram based on the present data.


title: Modeling Composites of Multi-Walled Carbon Nanotubes in Polycarbonate

abstract:
  High strain rate experiments performed on multi-walled carbon nanotubes and
polycarbonate composites (MWCNT-PC) have exhibited enhanced impact resistance
under a dynamic strain rate of nearly 2500/s with composition of only 0.5 to
2.0 percent of Multi walled carbon nanotubes(MWCNTs) in pure polycarbonate(PC).
Similarly, hardness and elastic modulus under static loads resulted in
significant increase depending upon the composition of MWCNTs in PC.The present
work aims to analyze these results by correlating the data to fit expressions
in generalizing the behavior of MWCNTs composition for MWCNT-PC composites
under both static and impact loads. As a result we found that an optimum
composition of 2.1 percent of MWCNTs exhibits maximum stress resistance within
elastic range under strain rates of nearly 2500/s for MWCNT-PC composites.The
results are critically dependent on the composition of MWCNTs and significantly
deteriorate below and above a threshold composition. A simple model based on
Lennard-Jones atom-atom based potential is formulated to compute static
properties of pure as well as composites of PC.


title: Polymer plats and multicomponent anyon gases

abstract:
  Anyon systems are studied in connection with several interesting applications
including high $T_C$ superconductivity and topological quantum computing. In
this work we show that these systems can be realized starting from directed
polymers braided together to form a nontrivial link configuration belonging to
the topological class of plats. The statistical sum of a such plat is related
here to the partition function of a two-component anyon gas. The constraints
that preserve the topological configuration of the plat are imposed on the
polymer trajectories using the so-called Gauss linking number, a topological
invariant that has already been well studied in polymer physics. Due to these
constraints, short-range forces act on the monomers or, equivalently, on the
anyon quasiparticles in a way that closely resembles the appearance of reaction
forces in the constrained systems of classical mechanics. If the polymers are
homogeneous, the anyon system reaches a self-dual point, in which these forces
vanish exactly. A class of self-dual solutions that minimize the energy of the
anyons is derived. The two anyon gas discussed here obeys an abelian
statistics, while for quantum computing it is known that nonabelian anyons are
necessary. However, this is a limitation due to the use of the Gauss linking
invariant to impose the topological constraints, which is a poor topological
invariant and is thus unable to capture the nonabelian characteristics of the
braided polymer chains. A more refined treatment of the topological constraints
would require more sophisticated topological invariants, but so far their
application to the statistical mechanics of linked polymers is an open problem.


title: Dark Radiation candidates after Planck

abstract:
  Recent Cosmic Microwave Background (CMB) results from the Planck satellite,
combined with previous CMB data and Hubble constant measurements from the
Hubble Space Telescope, provide a constraint on the effective number of
relativistic degrees of freedom of Neff=3.62^{+0.50}_{-0.48} at 95% CL. These
new measurements provide a unique opportunity to place limits on models
containing relativistic species at the decoupling epoch. Here we review the
bounds or the allowed parameter regions in sterile neutrino models, hadronic
axion models as well as on extended dark sectors with additional light species
based on the latest Planck CMB observations.


title: A New Bayesian Test to test for the Intractability-Countering Hypothesis

abstract:
  We present a new test of hypothesis in which we seek the probability of the
null conditioned on the data, where the null is a simplification undertaken to
counter the intractability of the more complex model, that the simpler null
model is nested within. With the more complex model rendered intractable, the
null model uses a simplifying assumption that capacitates the learning of an
unknown parameter vector given the data. Bayes factors are shown to be known
only up to a ratio of unknown data-dependent constants--a problem that cannot
be cured using prescriptions similar to those suggested to solve the problem
caused to Bayes factor computation, by non-informative priors. Thus, a new test
is needed in which we can circumvent Bayes factor computation. In this test, we
undertake generation of data from the model in which the null hypothesis is
true and can achieve support in the measured data for the null by comparing the
marginalised posterior of the model parameter given the measured data, to that
given such generated data. However, such a ratio of marginalised posteriors can
confound interpretation of comparison of support in one measured data for a
null, with that in another data set for a different null. Given an application
in which such comparison is undertaken, we alternatively define support in a
measured data set for a null by identifying the model parameters that are less
consistent with the measured data than is minimally possible given the
generated data, and realising that the higher the number of such parameter
values, less is the support in the measured data for the null. Then, the
probability of the null conditional on the data is given within an MCMC-based
scheme, by marginalising the posterior given the measured data, over parameter
values that are as, or more consistent with the measured data, than with the
generated data.


title: Dirac's discrete hypersurface deformation algebras

abstract:
  The diffeomorphism symmetry of general relativity leads in the canonical
formulation to constraints, which encode the dynamics of the theory. These
constraints satisfy a complicated algebra, known as Dirac's hypersurface
deformation algebra. This algebra has been a long standing challenge for
quantization. One reason is that discretizations, on which many quantum gravity
approaches rely, generically break diffeomorphism symmetry. In this work we
find a representation for the Dirac constraint algebra of hypersurface
deformations in a formulation of discrete 3D gravity and for the flat as well
as homogeneously curved sector of discrete 4D gravity. In these cases
diffeomorphism symmetry can be preserved. Furthermore we present different
versions of the hypersurface deformation algebra for the boundary of a simplex
in arbitrary dimensions.


title:
Towards a census of the Galactic anticentre star clusters - III: tracing
  the spiral structure in the Outer Disk

abstract:
  In this paper we investigate the nature of 27 star cluster candidates, most
of them projected towards the Galactic anticentre. We derive fundamental
parameters for 20 confirmed clusters, among these 7 are new identifications.
Four of the remaining are uncertain cases that require deeper photometry to
establish their nature, and 4 are probably field fluctuations. In addition, we
provide a partial census of the open clusters towards the Galactic anticentre.
We also include in this study some interesting objects outside the anticentre
region, in the second and third Galactic quadrants, mainly in the Perseus and
Outer arms. These clusters confirm the extension of the Outer arm along the
third quadrant. We also point out that the embedded cluster FSR 486, at a
distance of 7.2 +/- 1.3 kpc from de Sun, is projected on the line of sight of
the Local Group irregular dwarf galaxy IC 10. Thus, part of the unusual
properties of IC 10 may be explained by a Galactic contamination. We point out
the importance of embedded clusters in tracing the spiral structure.


title: Random time averaged diffusivities for L\'evy walks

abstract:
  We investigate a L\'evy-Walk alternating between velocities $\pm v_0$ with
opposite sign. The sojourn time probability distribution at large times is a
power law lacking its mean or second moment. The first case corresponds to a
ballistic regime where the ensemble averaged mean squared displacement (MSD) at
large times is $< x^2 > \propto t^2$, the latter to enhanced diffusion with $<
x^2 > \propto t^\nu$, $1<\nu<2$. The correlation function and the time averaged
MSD are calculated. In the ballistic case, the deviations of the time averaged
MSD from a purely ballistic behavior are shown to be distributed according to a
Mittag-Leffler density function. In the enhanced diffusion regime, the
fluctuations of the time averages MSD vanish at large times, yet very slowly.
In both cases we quantify the discrepancy between the time averaged and
ensemble averaged MSDs.


title:
A little scholium on Hilbert-Rohn via the total reality of $M$-curves:
  Riemann's flirt with Miss Ragsdale

abstract:
  This note presents an elementary proof of Hilbert's 1891 Ansatz of nesting
for $M$-sextics, along the line of Riemann's Nachlass 1857 and a simple
Harnack-style argument (1876). Our proof seems to have escaped the attention of
Hilbert (and all subsequent workers) [but alas turned out to contain a severe
gap, cf. Introduction for more!]. It uses a bit Poincar\'e's index formula
(1881/85). The method applies as well to prohibit Rohn's scheme 10/1, and
therefore all obstructions of Hilbert's 16th in degree $m=6$ can be explained
via the method of total reality. (The same ubiquity of the method is
conjectured in all degrees, and then suspected to offer new insights.) More
factually, a very simple and robust phenomenon of total reality on $M$-curves
of even order is described (the odd-order case being already settled in Gabard
2013), and it is speculated that this could be used as an attack upon the
(still open) Ragsdale conjecture for $M$-curves (positing that $| \chi|\le
k^2$). Of course a giant gap still remains to be bridged in case the latter
conjecture is true at all. Alas, the writer has little experimental evidence
for the truth of the conjecture, and the game can be a hazardous one. However
we suspect that the method of total reality should at least be capable of
recovering the weaker Petrovskii bound, or strengthened variants due to Arnold
1971. This text has therefore merely didactic character and offers no
revolutionary results, but tries to reactivate a very ancient method (due
basically to Riemann 1857) whose swing seems to have been somewhat
underestimated, at least outside of the conformal-mapping community.


title: Large scale absolute extensors

abstract:
  This paper is devoted to dualization of dimension-theoretical results from
the small scale to the large scale. So far there are two approaches for such
dualization: one consisting of creating analogs of small scale concepts and the
other amounting to the covering dimension of the Higson corona $\nu(X)$ of $X$.
The first approach was used by M.Gromov when defining the asymptotic dimension
$\asdim(X)$ of metric spaces $X$. The second approach was implicitly contained
in the paper \cite{Dran AsyTop} by Dranishnikov on asymptotic topology. It is
not known if the two approaches yield the same concept. However,
Dranishnikov-Keesling-Uspenskiy proved $\dim(\nu(X)\leq \asdim(X)$ and
Dranishnikov established that $\dim(\nu(X)= \asdim(X)$ provided $\asdim(X) <
\infty$. We characterize asymptotic dimension (for spaces of finite asymptotic
dimension) in terms of extensions of slowly oscillating functions to spheres.
Our approach is specifically designed to relate asymptotic dimension to the
covering dimension of the Higson corona $\nu(X)$ in case of proper metric
spaces $X$. As an application, we recover the results of
Dranishnikov-Keesling-Uspenskiy and Dranishnikov.


title: The least modulus for which consecutive polynomial values are distinct

abstract:
  Let $d\ge4$ and $c\in(-d,d)$ be relatively prime integers. We show that for
any sufficiently large integer $n$ (in particular $n>24310$ suffices for $4\le
d\le 36$), the smallest prime $p\equiv c\pmod d$ with $p\ge(2dn-c)/(d-1)$ is
the least positive integer $m$ with $2r(d)k(dk-c)\ (k=1,\ldots,n)$ pairwise
distinct modulo $m$, where $r(d)$ is the radical of $d$. We also conjecture
that for any integer $n>4$ the least positive integer $m$ such that
$|\{k(k-1)/2\ \mbox{mod}\ m:\ k=1,\ldots,n\}|= |\{k(k-1)/2\ \mbox{mod}\ m+2:\
k=1,\ldots,n\}|=n$ is the least prime $p\ge 2n-1$ with $p+2$ also prime.


title: The Localized Energy Distribution of Dark Energy Star Solutions

abstract:
  We examine the question of energy localization for an exact solution of
Einstein's equations with a scalar field corresponding to the phantom energy
interpretation of dark energy. We apply three different energy-momentum
complexes, the Einstein, Papapetrou and M{\o}ller prescriptions, to the
exterior metric and determine the energy distribution for each. Comparing the
results, we find that the three prescriptions yield identical energy
distributions.


title: The 6-strand braid group is CAT(0)

abstract:
  We show that braid groups with at most 6 strands are CAT(0) using the close
connection between these groups, the associated non-crossing partition
complexes and the embeddability of their diagonal links into spherical
buildings of type A. Furthermore, we prove that the orthoscheme complex of any
bounded graded modular complemented lattice is CAT(0), giving a partial answer
to a conjecture of Brady and McCammond.


title:
Approximation Algorithms for Vehicle Routing Problems with Stochastic
  Demands on Trees

abstract:
  We consider the vehicle routing problem with stochastic demands (VRPSD) on
tree structured networks with a single depot. The problem we are concerned with
in this paper is to find a set of tours for the vehicle with minimum expected
length. Every tour begins at the depot, visits a subset of customers and
returns to the depot without violating the capacity constraint. Randomized
approximation algorithm achieving approximation guarantees of 2 for
split-delivery VRPSD, and 3 for un-split delivery VRPSD are obtained.


title: Instability of black holes in massive gravity

abstract:
  We show that linear perturbations around the simplest black hole solution of
massive bi-gravity theories, the bi-Schwarzschild solution, exhibit an unstable
mode featuring the Gregory-Laflamme instability of higher-dimensional black
strings. The result is obtained for the massive gravity theory which is free
from the Boulware-Deser ghost, as well as for its extension with two dynamical
metrics. These results may indicate that static black holes in massive gravity
do not exist. For graviton mass of order of Hubble scale, however, the
instability timescale is of order of the Hubble time.


title:
Stochastic Memristive Devices for Computing and Neuromorphic
  Applications

abstract:
  Nanoscale resistive switching devices (memristive devices or memristors) have
been studied for a number of applications ranging from non-volatile memory,
logic to neuromorphic systems. However a major challenge is to address the
potentially large variations in space and in time in these nanoscale devices.
Here we show that in metal-filament based memristive devices the switching can
be fully stochastic. While individual switching events are random, the
distribution and probability of switching can be well predicted and controlled.
Rather than trying to force high switching probabilities using excessive
voltage or time, the inherent stochastic nature of resistive switching allows
these binary devices to be used as building blocks for novel error-tolerant
computing schemes such as stochastic computing and provide a needed "analog"
feature in neuromorphic applications. To verify such potential, we demonstrated
memristor-based stochastic bitstreams in both time and space domains, and show
that an array of binary memristors can act as a multi-level "analog" device for
neuromorphic applications.


title:
De Haas-van Alphen effect and Fermi surface properties of single crystal
  CrB2

abstract:
  We report the angular dependence of three distinct de Haas-van Alphen (dHvA)
frequencies of the torque magnetization in the itinerant antiferromagnet CrB2
at temperatures down to 0.3K and magnetic fields up to 14T. Comparison with the
calculated Fermi surface of nonmagnetic CrB2 suggests that two of the observed
dHvA oscillations arise from electron-like Fermi surface sheets formed by bands
with strong B-px,y character which should be rather insensitive to exchange
splitting. The measured effective masses of these Fermi surface sheets display
strong enhancements of up to a factor of two over the calculated band masses
which we attribute to electron-phonon coupling and electronic correlations. For
the temperature and field range studied, we do not observe signatures
reminiscent of the heavy d-electron bands expected for antiferromagnetic CrB2.
In view that the B-p bands are at the heart of conventional high-temperature
superconductivity in the isostructural MgB2, we consider possible implications
of our findings for nonmagnetic CrB2 and an interplay of itinerant
antiferromagnetism with superconductivity.


title:
The role of exterior Weyl fluids on compact stellar structures in
  Randall-Sundrum gravity

abstract:
  In the context of the Randall-Sundrum braneworld, the minimal geometric
deformation approach (MGD) is used to generate a new physically acceptable
interior solution to Einstein's field equations for a spherically symmetric
compact distribution. This new solution is used to elucidate the role of
exterior Weyl stresses from bulk gravitons on compact stellar distributions. We
found strong evidences showing that the exterior dark radiation ${\cal U}^+$
always increases both the pressure and the compactness of stellar structures,
and that the exterior "dark pressure" ${\cal P}^+$ always reduces them.


title:
Comparison of Thermal Neutron Detection Efficiency of $^{6}$Li
  Scintillation Glass and $^{3}$He Gas Proportional Tube

abstract:
  We report on a comparison study of the $^{3}$He gas proportional tube and the
$^{6}$Li incorporated scintillation glasses on thermal neutron detection
efficiency. Both $^{3}$He and $^{6}$Li are used commonly for thermal neutron
detection because of their high neutron capture absorption coefficient. By
using a neutron source $^{252}$Cf and a paraffin moderator in an alignment
system, we can get a small beam of thermal neutrons. A flash ADC is used to
measure the thermal neutron spectrum of each detector, and the detected number
of events is determined from the spectrum, then we can calculate the detection
efficiency of different detectors. Meanwhile, the experiment have been modeled
with GEANT4 to validate the results against the Monte Carlo simulation.


title: Can bimodality exist without phase transition?

abstract:
  Here we present an explicit counterexample to the widely spread beliefs about
an exclusive role of bimodality as the first order phase transition signal. On
the basis of an exactly solvable statistical model generalizing the statistical
multifragmentation model of nuclei we demonstrate that the bimodal nuclear
fragment size distributions can naturally appear in infinite system without a
phase transition. It appears at the supercritical temperatures due to the
negative values of the surface tension coefficient. The developed statistical
model corresponds to the compressible nuclear liquid with the tricritical
endpoint located at one third of the normal nuclear density.


title: Adiabaticity and diabaticity in strong-field ionization

abstract:
  If the photon energy is much less than the electron binding energy,
ionization of an atom by a strong optical field is often described in terms of
electron tunneling through the potential barrier resulting from the
superposition of the atomic potential and the potential associated with the
instantaneous electric component of the optical field. In the strict tunneling
regime, the electron response to the optical field is said to be adiabatic, and
nonadiabatic effects are assumed to be negligible. Here, we investigate to what
degree this terminology is consistent with a language based on the so-called
adiabatic representation. This representation is commonly used in various
fields of physics. For electronically bound states, the adiabatic
representation yields discrete potential energy curves that are connected by
nonadiabatic transitions. When applying the adiabatic representation to optical
strong-field ionization, a conceptual challenge is that the eigenstates of the
instantaneous Hamiltonian form a continuum; i.e., there are no discrete
adiabatic states. This difficulty can be overcome by applying an
analytic-continuation technique. In this way, we obtain a rigorous
classification of adiabatic states and a clear characterization of
(non)adiabatic and (non)diabatic ionization dynamics. Moreover, we distinguish
two different regimes within tunneling ionization and explain the dependence of
the ionization probability on the pulse envelope.


title: Weighted estimates for the multilinear maximal function

abstract:
  A formulation of the Carleson embedding theorem in the multilinear setting is
proved which allows to obtain a multilinear analogue of Sawyer's two weight
theorem for the multisublinear maximal function \mathcal{M} introduced in
Lerner et al. A multilinear version of the B_p theorem from Hyt\"onen and
P\'erez is also obtained and a mixed A_{\vec{P}}-W_{\vec{P}}^{\infty} bound for
\mathcal{M} is proved as well.


title: Mixture Gaussian Signal Estimation with L_infty Error Metric

abstract:
  We consider the problem of estimating an input signal from noisy measurements
in both parallel scalar Gaussian channels and linear mixing systems. The
performance of the estimation process is quantified by the $\ell_\infty$ norm
error metric. We first study the minimum mean $\ell_\infty$ error estimator in
parallel scalar Gaussian channels, and verify that, when the input is
independent and identically distributed (i.i.d.) mixture Gaussian, the Wiener
filter is asymptotically optimal with probability 1. For linear mixing systems
with i.i.d. sparse Gaussian or mixture Gaussian inputs, under the assumption
that the relaxed belief propagation (BP) algorithm matches Tanaka's fixed point
equation, applying the Wiener filter to the output of relaxed BP is also
asymptotically optimal with probability 1. However, in order to solve the
practical problem where the signal dimension is finite, we apply an estimation
algorithm that has been proposed in our previous work, and illustrate that an
$\ell_\infty$ error minimizer can be approximated by an $\ell_p$ error
minimizer provided the value of $p$ is properly chosen.


title:
Direct Measurement of the Bubble Nucleation Energy Threshold in a CF3I
  Bubble Chamber

abstract:
  We have directly measured the energy threshold and efficiency for bubble
nucleation from iodine recoils in a CF3I bubble chamber in the energy range of
interest for a dark matter search. These interactions cannot be probed by
standard neutron calibration methods, so we develop a new technique by
observing the elastic scattering of 12 GeV/c negative pions. The pions are
tracked with a silicon pixel telescope and the reconstructed scattering angle
provides a measure of the nuclear recoil kinetic energy. The bubble chamber was
operated with a nominal threshold of (13.6+-0.6) keV. Interpretation of the
results depends on the response to fluorine and carbon recoils, but in general
we find agreement with the predictions of the classical bubble nucleation
theory. This measurement confirms the applicability of CF3I as a target for
spin-independent dark matter interactions and represents a novel technique for
calibration of superheated fluid detectors.


title:
KOI-200b and KOI-889b: two transiting exoplanets detected and
  characterized with Kepler, SOPHIE and HARPS-N

abstract:
  We present the detection and characterization of the two new transiting,
close-in, giant extrasolar planets KOI-200b and KOI-889b. They were first
identified by the Kepler team as promising candidates from photometry of the
Kepler satellite, then we established their planetary nature thanks to the
radial velocity follow-up jointly secured with the spectrographs SOPHIE and
HARPS-N. Combined analyses of the whole datasets allow the two planetary
systems to be characterized. The planet KOI-200b has mass and radius of 0.68
+/- 0.09 M_Jup and 1.32 +/- 0.14 R_Jup; it orbits in 7.34 days a F8V host star
with mass and radius of 1.40 (+0.14/-0.11) M_Sun and 1.51 +/- 0.14 R_Sun.
KOI-889b is a massive planet with mass and radius of 9.9 +/- 0.5 M_Jup and 1.03
+/- 0.06 R_Jup; it orbits in 8.88 days an active G8V star with a rotation
period of 19.2 +/- 0.3 days, and mass and radius of 0.88 +/- 0.06 M_Sun and
0.88 +/- 0.04 R_Sun. Both planets lie on eccentric orbits and are located just
at the frontier between regimes where the tides can explain circularization and
where tidal effects are negligible. The two planets are among the first ones
detected and characterized thanks to observations secured with HARPS-N, the new
spectrograph recently mounted at the Telescopio Nazionale Galileo. These
results illustrate the benefits that could be obtained from joint studies using
two spectrographs as SOPHIE and HARPS-N.


title: Poisson and Hochschild cohomology and the semiclassical limit

abstract:
  Let $B$ be a quantum algebra possessing a semiclassical limit $A$. We show
that under certain hypotheses $B^e$ can be thought of as a deformation of the
Poisson enveloping algebra of $A$, and we give a criterion for the Hochschild
cohomology of $B$ to be a deformation of the Poisson cohomology of $A$ in the
case that $B$ is Koszul. We verify that condition for the algebra of $2\times
2$ quantum matrices and calculate its Hochschild cohomology and the Poisson
cohomology of its semiclassical limit.


title:
Low-rank approximate inverse for preconditioning tensor-structured
  linear systems

abstract:
  In this paper, we propose an algorithm for the construction of low-rank
approximations of the inverse of an operator given in low-rank tensor format.
The construction relies on an updated greedy algorithm for the minimization of
a suitable distance to the inverse operator. It provides a sequence of
approximations that are defined as the projections of the inverse operator in
an increasing sequence of linear subspaces of operators. These subspaces are
obtained by the tensorization of bases of operators that are constructed from
successive rank-one corrections. In order to handle high-order tensors,
approximate projections are computed in low-rank Hierarchical Tucker subsets of
the successive subspaces of operators. Some desired properties such as symmetry
or sparsity can be imposed on the approximate inverse operator during the
correction step, where an optimal rank-one correction is searched as the tensor
product of operators with the desired properties. Numerical examples illustrate
the ability of this algorithm to provide efficient preconditioners for linear
systems in tensor format that improve the convergence of iterative solvers and
also the quality of the resulting low-rank approximations of the solution.


title:
Pattern formation for the Swift-Hohenberg equation on the hyperbolic
  plane

abstract:
  We present an overview of pattern formation analysis for an analogue of the
Swift-Hohenberg equation posed on the real hyperbolic space of dimension two,
which we identify with the Poincar\'e disc D. Different types of patterns are
considered: spatially periodic stationary solutions, radial solutions and
traveling waves, however there are significant differences in the results with
the Euclidean case. We apply equivariant bifurcation theory to the study of
spatially periodic solutions on a given lattice of D also called H-planforms in
reference with the "planforms" introduced for pattern formation in Euclidean
space. We consider in details the case of the regular octagonal lattice and
give a complete descriptions of all H-planforms bifurcating in this case. For
radial solutions (in geodesic polar coordinates), we present a result of
existence for stationary localized radial solutions, which we have adapted from
techniques on the Euclidean plane. Finally, we show that unlike the Euclidean
case, the Swift-Hohenberg equation in the hyperbolic plane undergoes a Hopf
bifurcation to traveling waves which are invariant along horocycles of D and
periodic in the "transverse" direction. We highlight our theoretical results
with a selection of numerical simulations.


title:
Analysis of Realized Volatility in Two Trading Sessions of the Japanese
  Stock Market

abstract:
  We analyze realized volatilities constructed using high-frequency stock data
on the Tokyo Stock Exchange. In order to avoid non-trading hours issue in
volatility calculations we define two realized volatilities calculated
separately in the two trading sessions of the Tokyo Stock Exchange, i.e.
morning and afternoon sessions. After calculating the realized volatilities at
various sampling frequencies we evaluate the bias from the microstructure noise
as a function of sampling frequency. Taking into account of the bias to
realized volatility we examine returns standardized by realized volatilities
and confirm that price returns on the Tokyo Stock Exchange are described
approximately by Gaussian time series with time-varying volatility, i.e.
consistent with a mixture of distributions hypothesis.


title: Paging with dynamic memory capacity

abstract:
  We study a generalization of the classic paging problem that allows the
amount of available memory to vary over time - capturing a fundamental property
of many modern computing realities, from cloud computing to multi-core and
energy-optimized processors. It turns out that good performance in the
"classic" case provides no performance guarantees when memory capacity
fluctuates: roughly speaking, moving from static to dynamic capacity can mean
the difference between optimality within a factor 2 in space and time, and
suboptimality by an arbitrarily large factor. More precisely, adopting the
competitive analysis framework, we show that some online paging algorithms,
despite having an optimal (h,k)-competitive ratio when capacity remains
constant, are not (3,k)-competitive for any arbitrarily large k in the presence
of minimal capacity fluctuations. In this light it is surprising that several
classic paging algorithms perform remarkably well even if memory capacity
changes adversarially - even without taking those changes into explicit
account! In particular, we prove that LFD still achieves the minimum number of
faults, and that several classic online algorithms such as LRU have a "dynamic"
(h,k)-competitive ratio that is the best one can achieve without knowledge of
future page requests, even if one had perfect knowledge of future capacity
fluctuations (an exact characterization of this ratio shows it is almost,
albeit not quite, equal to the "classic" ratio k/(k-h+1)). In other words, with
careful management, knowing/predicting future memory resources appears far less
crucial to performance than knowing/predicting future data accesses.


title: Multidimensional Catalan and related numbers as Hausdorff moments

abstract:
  We study integral representation of so-called $d$-dimensional Catalan numbers
$C_{d}(n)$, defined by $[\prod_{p=0}^{d-1} \frac{p!}{(n+p)!}] (d n)!$, $d = 2,
3, ...$, $n=0, 1, ...$. We prove that the $C_{d}(n)$'s are the $n$th Hausdorff
power moments of positive functions $W_{d}(x)$ defined on $x\in[0, d^d]$. We
construct exact and explicit forms of $W_{d}(x)$ and demonstrate that they can
be expressed as combinations of $d-1$ hypergeometric functions of type
$_{d-1}F_{d-2}$ of argument $x/d^d$. These solutions are unique. We analyse
them analytically and graphically. A combinatorially relevant, specific
extension of $C_{d}(n)$ for $d$ even in the form $D_{d}(n)=[\prod_{p = 0}^{d-1}
\frac{p!}{(n+p)!}] [\prod_{q = 0}^{d/2 - 1} \frac{(2 n + 2 q)!}{(2 q)!}]$ is
analyzed along the same lines.


title: Circle of Sarkisov links on a Fano $3$-fold

abstract:
  For a general Fano $3$-fold of index $1$ in the weighted projective space
$\mathbb{P}(1,1,1,1,2,2,3)$ we construct $2$ new birational models that are
Mori fibre spaces, in the framework of the so-called Sarkisov program. We
highlight a relation between the corresponding birational maps, as a circle of
Sarkisov links, visualising the notion of relations (due to Kaloghiros) in
Sarkisov program.


title: Melting of graphene clusters

abstract:
  Density-functional tight-binding and classical molecular dynamics simulations
are used to investigate the structural deformations and melting of planar
carbon nano-clusters $C_{N}$ with N=2-55. The minimum energy configurations for
different clusters are used as starting configuration for the study of the
temperature effects on the bond breaking/rotation in carbon lines (N$<$6),
carbon rings (5$<$N$<$19) and graphene nano-flakes. The larger the rings
(graphene nano-flake) the higher the transition temperature (melting point)
with ring-to-line (perfect-to-defective) transition structures. The melting
point was obtained by using the bond energy, the Lindemann criteria, and the
specific heat. We found that hydrogen-passivated graphene nano-flakes
(C$_{N}$H$_M$) have a larger melting temperature with a much smaller dependence
on its size. The edges in the graphene nano-flakes exhibit several different
meta-stable configurations (isomers) during heating before melting occurs.


title: Critical Groups of Graphs with Dihedral Actions

abstract:
  In this paper we consider the critical group of finite connected graphs which
admit harmonic actions by the dihedral group $D_n$. In particular, we show that
if the orbits of the $D_n$-action all have either $n$ or $2n$ points then the
critical group of such a graph can be decomposed in terms of the critical
groups of the quotients of the graph by certain subgroups of the automorphism
group. This is analogous to a theorem of Kani and Rosen which decomposes the
Jacobians of algebraic curves with a $D_n$-action.


title: Equilibration of a one-dimensional quantum liquid

abstract:
  We review some of the recent results on equilibration of one-dimensional
quantum liquids. The low-energy properties of these systems are described by
the Luttinger liquid theory, in which the excitations are bosonic
quasiparticles. At low temperatures the relaxation of the gas of excitations
toward full equilibrium is exponentially slow. In electronic Luttinger liquids
these relaxation processes involve backscattering of electrons and give rise to
interesting corrections to the transport properties of one-dimensional
conductors. We focus on the phenomenological theory of the equilibration of a
quantum liquid and obtain an expression for the relaxation rate in terms of the
excitation spectrum.


title:
Extended dynamic Mott-transition in the two-band Hubbard model out of
  equilibrium

abstract:
  We reformulate the time-dependent Gutzwiller approximation by M. Schir\'o and
M. Fabrizio [Phys. Rev. Lett. 105, 076401 (2010)] in the framework of
slave-boson mean-field theory, which is used to investigate the dynamical Mott
transition of the generic two-band Hubbard model at half filling upon an
interaction quench. Interorbital fluctuations lead to notable changes with
respect to the single-band case. The singular dynamical transition is replaced
by a broad regime of long-lived fluctuations between metallic and insulating
states, accompanied by intriguing precursor behavior. A mapping to a spin model
proves helpful to analyze the different regions in terms of the evolution of an
Ising-like order parameter. Contrary to the static case, singlet occupations
remain vital in the Mott-insulating regime with finite Hund's exchange.


title: Meson Exchange Current (MEC) Models in Neutrino Interaction Generators

abstract:
  Understanding of the so-called 2 particle-2 hole (2p-2h) effect is an urgent
program in neutrino interaction physics for current and future oscillation
experiments. Such processes are believed to be responsible for the event
excesses observed by recent neutrino experiments. The 2p-2h effect is dominated
by the meson exchange current (MEC), and is accompanied by a 2-nucleon emission
from the primary vertex, instead of a single nucleon emission from the
charged-current quasi-elastic (CCQE) interaction.
  Current and future high resolution experiments can potentially nail down this
effect. For this reason, there are world wide efforts to model and implement
this process in neutrino interaction simulations. In these proceedings, I would
like to describe how this channel is modeled in neutrino interaction
generators.


title:
Magnetic fields around evolved stars: further observations of H$_2$O
  maser polarization

abstract:
  We aim to detect the magnetic field and infer its properties around four AGB
stars using H$_2$O maser observations. The sample we observed consists of the
following sources: the semi-regular variable RT Vir and the Mira variables AP
Lyn, IK Tau, and IRC+60370. We observed the 6$_{1,6}-5_{2,3}$ H$_2$O maser
rotational transition, in full-polarization mode, to determine its linear and
circular polarization. Based on the Zeeman effect, one can infer the properties
of the magnetic field from the maser polarization analysis. We detected a total
of 238 maser features, in three of the four observed sources. No masers were
found toward AP Lyn. The observed masers are all located between 2.4 and 53.0
AU from the stars. Linear and circular polarization was found in 18 and 11
maser features, respectively. We more than doubled the number of AGB stars in
which magnetic field has been detected from H$_2$O maser polarization, as our
results confirm the presence of fields around IK Tau, RT Vir and IRC+60370. The
strength of the field along the line of sight is found to be between 47 and 331
mG in the H$_2$O maser region. Extrapolating this result to the surface of the
stars, assuming a toroidal field ($\propto$ r$^{-1}$), we find magnetic fields
of 0.3-6.9 G on the stellar surfaces. If, instead of a toroidal field, we
assume a poloidal field ($\propto$ r$^{-2}$), then the extrapolated magnetic
field strength on the stellar surfaces are in the range between 2.2 and
$\sim$115 G. Finally, if a dipole field ($\propto$ r$^{-3}$) is assumed, the
field strength on the surface of the star is found to be between 15.8 and
$\sim$1945 G. The magnetic energy of our sources is higher than the thermal and
kinetic energy in the H$_2$O maser region of this class of objects. This leads
us to conclude that, indeed, magnetic fields probably play an important role in
shaping the outflows of evolved stars. (abridged)


title:
Aspects of Quantum Corrections in a Lorentz-violating Extension of the
  Abelian Higgs Model

abstract:
  We investigate new aspects related to the abelian gauge-Higgs model with the
addition of the Carroll-Field-Jackiw term. We focus on one-loop quantum
corrections to the photon and Higgs sectors due to spontaneous breaking of
gauge symmetry and show that new finite and definite Lorentz-breaking terms are
induced. Specifically in the gauge sector, a CPT-even aether term is induced.
Besides, aspects of the one-loop renormalization of the background vector
dependent terms are discussed.


title:
Rate-optimal Bayesian intensity smoothing for inhomogeneous Poisson
  processes

abstract:
  We apply nonparametric Bayesian methods to study the problem of estimating
the intensity function of an inhomogeneous Poisson process. We exhibit a prior
on intensities which both leads to a computationally feasible method and enjoys
desirable theoretical optimality properties. The prior we use is based on
B-spline expansions with free knots, adapted from well-established methods used
in regression, for instance. We illustrate its practical use in the Poisson
process setting by analyzing count data coming from a call centre.
Theoretically we derive a new general theorem on contraction rates for
posteriors in the setting of intensity function estimation. Practical choices
that have to be made in the construction of our concrete prior, such as
choosing the priors on the number and the locations of the spline knots, are
based on these theoretical findings. The results assert that when properly
constructed, our approach yields a rate-optimal procedure that automatically
adapts to the regularity of the unknown intensity function.


title: Stable and metastable hard sphere crystals in Fundamental Measure Theory

abstract:
  Using fully minimized fundamental measure functionals, we investigate free
energies, vacancy concentrations and density distributions for bcc, fcc and hcp
hard-sphere crystals. Results are complemented by an approach due to Stillinger
which is based on expanding the crystal partition function in terms of the
number n of free particles while the remaining particles are frozen at their
ideal lattice positions. The free energies of fcc/hcp and one branch of bcc
agree well with Stillinger's approach truncated at n=2. A second branch of bcc
solutions features rather spread-out density distributions around lattice sites
and large equilibrium vacancy concentrations and is presumably linked to the
shear instability of the bcc phase. Within fundamental measure theory and the
Stillinger approach (n=2), hcp is more stable than fcc by a free energy per
particle of about 0.001 k_{B}T. In previous simulation work, the reverse
situation has been found which can be rationalized in terms of effects due to a
correlated motion of at least 5 particles in the Stillinger picture.


title:
On fracture criteria for dynamic crack propagation in elastic materials
  with couple stresses

abstract:
  The focus of the article is on fracture criteria for dynamic crack
propagation in elastic materials with microstructures. Steady-state propagation
of a Mode III semi-infinite crack subject to loading applied on the crack
surfaces is considered. The micropolar behavior of the material is described by
the theory of couple-stress elasticity developed by Koiter. This constitutive
model includes the characteristic lengths in bending and torsion, and thus it
is able to account for the underlying microstructures of the material. Both
translational and micro-rotational inertial terms are included in the balance
equations, and the behavior of the solution near to the crack tip is
investigated by means of an asymptotic analysis. The asymptotic fields are used
to evaluate the dynamic J-integral for a couple-stress material, and the energy
release rate is derived by the corresponding conservation law. The propagation
stability is studied according to the energy-based Griffith criterion and the
obtained results are compared to those derived by the application of the
maximum total shear stress criterion.


title: Chiral Disorder and Random Matrix Theory with Magnetism

abstract:
  We revisit the concept of chiral disorder in QCD in the presence of a QED
magnetic field |eH|. Weak magnetism corresponds to |eH| < 1/rho^2 with
rho\approx (1/3) fm the vacuum instanton size, while strong magnetism the
reverse. Asymptotics (ultra-strong magnetism) is in the realm of perturbative
QCD. We analyze weak magnetism using the concept of the quark return
probability in the diffusive regime of chiral disorder. The result is in
agreement with expectations from chiral perturbation theory. We analyze strong
and ultra-strong magnetism in the ergodic regime using random matrix theory
including the effects of finite temperature. The strong magnetism results are
in agreement with the currently reported lattice data in the presence of a
small shift of the Polyakov line. The ultra-strong magnetism results are
consistent with expectations from perturbative QCD. We suggest a chiral random
matrix effective action with matter and magnetism to analyze the QCD phase
diagram near the critical points under the influence of magnetism.


title: Torus knots as Hopfions

abstract:
  We present a direct connection between torus knots and Hopfions by finding
stable and static solutions of the extended Faddeev-Skyrme model with a
ferromagnetic potential term. (P,Q)--torus knots consisting of |Q| sine-Gordon
kink strings twisted P/Q times into the poloidal cycle along the toroidal cycle
on a toroidal domain wall carry the Hopf charge PQ, which demonstrates that
Hopfions can be further classified according to torus knot type.


title: Long-term evolution of the neutron-star spin period of SXP 1062

abstract:
  The Be/X-ray binary SXP1062 is of especial interest owing to the large spin
period of the neutron star, its large spin-down rate, and the association with
a supernova remnant constraining its age. This makes the source an important
probe for accretion physics. To investigate the long-term evolution of the spin
period and associated spectral variations, we performed an XMM-Newton
target-of-opportunity observation of SXP1062 during X-ray outburst. Spectral
and timing analysis of the XMM-Newton data was compared with previous studies,
as well as complementary Swift/XRT monitoring and optical spectroscopy with the
SALT telescope were obtained. The spin period was measured to be P_s
=(1071.01+-0.16) s on 2012 Oct 14. The X-ray spectrum is similar to that of
previous observations. No convincing cyclotron absorption features, which could
be indicative for a high magnetic field strength, are found. The
high-resolution RGS spectra indicate the presence of emission lines, which may
not completely be accounted for by the SNR emission. The comparison of
multi-epoch optical spectra suggest an increasing size or density of the
decretion disc around the Be star. SXP1062 showed a net spin-down with an
average of (2.27+-0.44) s/yr over a baseline of 915 days.


title:
Spaces, Trees and Colors: The Algorithmic Landscape of Document
  Retrieval on Sequences

abstract:
  Document retrieval is one of the best established information retrieval
activities since the sixties, pervading all search engines. Its aim is to
obtain, from a collection of text documents, those most relevant to a pattern
query. Current technology is mostly oriented to "natural language" text
collections, where inverted indices are the preferred solution. As successful
as this paradigm has been, it fails to properly handle some East Asian
languages and other scenarios where the "natural language" assumptions do not
hold. In this survey we cover the recent research in extending the document
retrieval techniques to a broader class of sequence collections, which has
applications bioinformatics, data and Web mining, chemoinformatics, software
engineering, multimedia information retrieval, and many others. We focus on the
algorithmic aspects of the techniques, uncovering a rich world of relations
between document retrieval challenges and fundamental problems on trees,
strings, range queries, discrete geometry, and others.


title: N2-associated surface warming on early Mars

abstract:
  Early Mars may have had a warmer and denser atmosphere allowing for the
presence of liquid water on the surface. However, climate model studies have
not been able to reproduce these conditions even with a CO2 atmosphere of
several bars. Recent 3D simulations of the early Mars climate show that mean
surface temperatures only slightly below 273K could be reached locally.
  We want to investigate the effect of increased partial pressures of N2 on
early Mars' surface temperature by including pressure broadening of absorption
lines and collision-induced N2-N2 absorption.
  A 1D radiative-convective cloud-free atmospheric model was used to calculate
temperature profiles and surface conditions. We performed a parameter study
varying the N2 partial pressures from 0 to 0.5bar at CO2 partial pressures
between 0.02bar and 3bar. These values are consistent with existing estimates
of the initial, pre-Noachian reservoir. Solar insolation was set to be
consistent with the late Noachian.
  Our 1D global mean simulations clearly show that enhanced N2 content in the
Martian atmosphere could have increased surface temperatures. An additional
greenhouse warming of up to 13K was found at a high N2 partial pressure of
0.5bar. Still, even at this N2 partial pressure, global mean surface
temperatures remained below 273K, i.e. the freezing point of water. However,
given the magnitude of the N2-induced surface warming and the results of recent
3D studies which show that local mean surface temperatures are not much lower
than 273K, our results imply that the presence of atmospheric N2 could have led
to almost continously habitable mean surface conditions in some regions. In
addition, atmospheric water column amounts increased by up to a factor of 6 in
response to the surface warming, indicating that precipitation might also
increase upon increasing N2 partial pressure.


title:
Critical current densities and microstructures in Rod-in-Tube and Tube
  Type Nb3Sn strands - Present status and prospects for improvement

abstract:
  In this work, the transport and magnetization properties of
distributed-barrier Rod-in-Tube (RIT) strands and Tube Type strands are
studied. While Tube Type strands had smaller magnetizations and thus better
stabilities in the low field region, their 12 T non-Cu Jcs were somewhat
smaller than those of the RIT strands. Microstructures were investigated in
order to find out the reasons for the difference in non-Cu Jc values. Their
grain size and stoichiometry were found to be comparable, leading to similar
layer Jcs. Accordingly it was determined that the lower A15 area fraction
rather than the quality of A15 layer was the cause of the discrepancy in non-Cu
Jc. Subsequently, the area utilizations of subelements were investigated. While
for a RIT strand the fine grain (FG) A15 area occupies ~60% of a subelement,
for a Tube Type strand it is no more than 40%. Further analysis indicates that
the low FG area fraction in a Tube Type strand is attributed to its much larger
unreacted Nb area fraction. Finally, a simple change in strand architecture is
proposed to reduce the unreacted Nb area fraction.


title:
Displacement Convexity, A Useful Framework for the Study of Spatially
  Coupled Codes

abstract:
  Spatial coupling has recently emerged as a powerful paradigm to construct
graphical models that work well under low-complexity message-passing
algorithms. Although much progress has been made on the analysis of spatially
coupled models under message passing, there is still room for improvement, both
in terms of simplifying existing proofs as well as in terms of proving
additional properties.
  We introduce one further tool for the analysis, namely the concept of
displacement convexity. This concept plays a crucial role in the theory of
optimal transport and, quite remarkably, it is also well suited for the
analysis of spatially coupled systems. In cases where the concept applies,
displacement convexity allows functionals of distributions which are not convex
in the usual sense to be represented in an alternative form, so that they are
convex with respect to the new parametrization. As a proof of concept we
consider spatially coupled $(l,r)$-regular Gallager ensembles when transmission
takes place over the binary erasure channel. We show that the potential
function of the coupled system is displacement convex. Due to possible
translational degrees of freedom convexity by itself falls short of
establishing the uniqueness of the minimizing profile. For the spatially
coupled $(l,r)$-regular system strict displacement convexity holds when a
global translation degree of freedom is removed. Implications for the
uniqueness of the minimizer and for solutions of the density evolution equation
are discussed.


title: Near-Optimal Stochastic Threshold Group Testing

abstract:
  We formulate and analyze a stochastic threshold group testing problem
motivated by biological applications. Here a set of $n$ items contains a subset
of $d \ll n$ defective items. Subsets (pools) of the $n$ items are tested --
the test outcomes are negative, positive, or stochastic (negative or positive
with certain probabilities that might depend on the number of defectives being
tested in the pool), depending on whether the number of defective items in the
pool being tested are fewer than the {\it lower threshold} $l$, greater than
the {\it upper threshold} $u$, or in between. The goal of a {\it stochastic
threshold group testing} scheme is to identify the set of $d$ defective items
via a "small" number of such tests. In the regime that $l = o(d)$ we present
schemes that are computationally feasible to design and implement, and require
near-optimal number of tests (significantly improving on existing schemes). Our
schemes are robust to a variety of models for probabilistic threshold group
testing.


title: Universality of the momentum band density of periodic networks

abstract:
  The momentum spectrum of a periodic network (quantum graph) has a band-gap
structure. We investigate the relative density of the bands or, equivalently,
the probability that a randomly chosen momentum belongs to the spectrum of the
periodic network. We show that this probability exhibits universal properties.
More precisely, the probability to be in the spectrum does not depend on the
edge lengths (as long as they are generic) and is also invariant within some
classes of graph topologies.


title:
Differential Geometrically Consistent Artificial Viscosity in Comoving
  Curvilinear Coordinates

abstract:
  Context. High-resolution numerical methods have been developed for nonlinear,
discontinuous problems as they appear in simulations of astrophysical objects.
One of the strategies applied is the concept of artificial viscosity. Aims.
Grid-based numerical simulations ideally utilize problem-oriented grids in
order to minimize the necessary number of cells at a given (desired) spatial
resolution. We want to propose a modified tensor of artificial viscosity which
is employable for generally comoving, curvilinear grids. Methods. We study a
differential geometrically consistent artificial viscosity analytically and
visualize a comparison of our result to previous implementations by applying it
to a simple self-similar velocity field. We give a general introduction to
artificial viscosity first and motivate its application in numerical analysis.
Then we present how a tensor of artificial viscosity has to be designed when
going beyond common static Eulerian or Lagrangian comoving rectangular grids.
Results. We find that in comoving, curvilinear coordinates the isotropic
(pressure) part of the tensor of artificial viscosity has to be modified
metrically in order for it to fulfill all its desired properties.


title:
Doping Dependence of Correlation Effects in K{1-x}Fe{2-y}Se2
  Superconductor: LDA'+DMFT Investigation

abstract:
  We present detailed LDA'+DMFT investigation of doping dependence of
correlation effects in novel K{1-x}Fe{2-y}Se2 superconductor. Calculations were
performed at four different hole doping levels, starting from hypothetical
stoichiometric composition with total number of electrons equal to 29 per unit
cell through 28 and 27.2 electrons towards the case of 26.52, which corresponds
to chemical composition K{0.76}Fe{1.72}Se2 studied in recent ARPES experiments.
In general case the increase of hole doping leads to quasiparticle bands in
wide energy window +/-2 eV around the Fermi level becoming more broadened by
lifetime effects, while correlation induced compression of Fe-3d LDA'
bandwidths stays almost the same and of the order of ~1.3 for all hole
concentrations. However close to the Fermi level situation is more complicated.
Here in the energy interval from -1.0 eV to 0.4 eV the bare Fe-3d LDA' bands
are compressed by significantly larger renormalization factors up to 5 with
hole doping increase, while the value of Coulomb interaction remains the same.
This fact manifests the increase of correlation effects with hole doping in
K{1-x}Fe{2-y}Se2 system. Moreover in contrast to typical pnictides
K{1-x}Fe{2-y}Se2 does not have well defined quasiparticle bands on the Fermi
leves but pseudogap like "dark" region instead. We also find that with the
growth of hole doping Fe-3d orbitals of various symmetries are affected by
correlations in a different way in different parts of Brillouin zone. To
illustrate this we determine quasiparticle mass renormalization factors and
energy shifts, which transform the bare Fe-3d LDA' bands of various symmetries
into LDA'+DMFT quasiparticle bands. These renormalization factors effectively
mimic more complicated energy dependent self-energy effects and can be used to
analyze the available ARPES data.


title: Neutrino Mass in TeV-Scale New Physics Models

abstract:
  This is a short review about relations between new scalars and mechanisms to
generate neutrino masses. We investigate leptohilic scalars whose Yukawa
interactions are only with leptons. We discuss possibilities that measurements
of their leptonic decays provide information on how neutrino masses are
generated and on parameters in the neutrino mass matrix (e.g. the lightest
neutrino mass).


title: Lagrangian Cobordism and Fukaya Categories

abstract:
  Given a symplectic manifold M, we consider a category with objects finite
ordered families of Lagrangian submanifolds of M (subject to certain additional
constraints) and with morphisms Lagrangian cobordisms relating them. We
construct a functor that maps this category to a variant of the derived Fukaya
category of M in a way that takes into account the triangulated structure of
the latter.


title: Robust Polyhedral Regularization

abstract:
  In this paper, we establish robustness to noise perturbations of polyhedral
regularization of linear inverse problems. We provide a sufficient condition
that ensures that the polyhedral face associated to the true vector is equal to
that of the recovered one. This criterion also implies that the $\ell^2$
recovery error is proportional to the noise level for a range of parameter. Our
criterion is expressed in terms of the hyperplanes supporting the faces of the
unit polyhedral ball of the regularization. This generalizes to an arbitrary
polyhedral regularization results that are known to hold for sparse synthesis
and analysis $\ell^1$ regularization which are encompassed in this framework.
As a byproduct, we obtain recovery guarantees for $\ell^\infty$ and
$\ell^1-\ell^\infty$ regularization.


title: Automated Alignment of Imperfect EM Images for Neural Reconstruction

abstract:
  The most established method of reconstructing neural circuits from animals
involves slicing tissue very thin, then taking mosaics of electron microscope
(EM) images. To trace neurons across different images and through different
sections, these images must be accurately aligned, both with the others in the
same section and to the sections above and below. Unfortunately, sectioning and
imaging are not ideal processes - some of the problems that make alignment
difficult include lens distortion, tissue shrinkage during imaging, tears and
folds in the sectioned tissue, and dust and other artifacts. In addition the
data sets are large (hundreds of thousands of images) and each image must be
aligned with many neighbors, so the process must be automated and reliable.
This paper discusses methods of dealing with these problems, with numeric
results describing the accuracy of the resulting alignments.


title: Convergence of bi-measure R-tree and the pruning process

abstract:
  In [Aldous,Pitman,1998] a tree-valued Markov chain is derived by pruning off
more and more subtrees along the edges of a Galton-Watson tree. More recently,
in [Abraham,Delmas,2012], a continuous analogue of the tree-valued pruning
dynamics is constructed along L\'evy trees. In the present paper, we provide a
new topology which allows to link the discrete and the continuous dynamics by
considering them as instances of the same strong Markov process with different
initial conditions. We construct this pruning process on the space of so-called
bi-measure trees, which are metric measure spaces with an additional pruning
measure. The pruning measure is assumed to be finite on finite trees, but not
necessarily locally finite. We also characterize the pruning process
analytically via its Markovian generator and show that it is continuous in the
initial bi-measure tree. A series of examples is given, which include the
finite variance offspring case where the pruning measure is the length measure
on the underlying tree.


title: Sub-barrier capture reactions with $^{16,18}$O and $^{40,48}$Ca beams

abstract:
  Various sub-barrier capture reactions with beams $^{16,18}$O and $^{40,48}$Ca
are treated within the quantum diffusion approach. The role of neutron transfer
in these capture reactions is discussed. The quasielastic and capture barrier
distributions are analyzed and compared with the recent experimental data.


title:
Characterisation of global flow and local fluctuations in 3D SPH
  simulations of protoplanetary discs

abstract:
  A complete and detailed knowledge of the structure of the gaseous component
in protoplanetary discs is essential to the study of dust evolution during the
early phases of pre-planetesimal formation. The aim of this paper is to
determine if three-dimensional accretion discs simulated by the Smoothed
Particle Hydrodynamics (SPH) method can reproduce the observational data now
available and the expected turbulent nature of protoplanetary discs. The
investigation is carried out by setting up a suite of diagnostic tools
specifically designed to characterise both the global flow and the fluctuations
of the gaseous disc. The main result concerns the role of the artificial
viscosity implementation in the SPH method: in addition to the already known
ability of SPH artificial viscosity to mimic a physical-like viscosity under
specific conditions, we show how the same artificial viscosity prescription
behaves like an implicit turbulence model. In fact, we identify a threshold for
the parameters in the standard artificial viscosity above which SPH disc models
present a cascade in the power spectrum of velocity fluctuations, turbulent
diffusion and a mass accretion rate of the same order of magnitude as measured
in observations. Furthermore, the turbulence properties observed locally in SPH
disc models are accompanied by meridional circulation in the global flow of the
gas, proving that the two mechanisms can coexist.


title: Implementing hash-consed structures in Coq

abstract:
  We report on three different approaches to use hash-consing in programs
certified with the Coq system, using binary decision diagrams (BDD) as running
example. The use cases include execution inside Coq, or execution of the
extracted OCaml code. There are different trade-offs between faithful use of
pristine extracted code, and code that is fine-tuned to make use of OCaml
programming constructs not available in Coq. We discuss the possible
consequences in terms of performances and guarantees.


title: Polynomial Systems Solving by Fast Linear Algebra

abstract:
  Polynomial system solving is a classical problem in mathematics with a wide
range of applications. This makes its complexity a fundamental problem in
computer science. Depending on the context, solving has different meanings. In
order to stick to the most general case, we consider a representation of the
solutions from which one can easily recover the exact solutions or a certified
approximation of them. Under generic assumption, such a representation is given
by the lexicographical Gr\"obner basis of the system and consists of a set of
univariate polynomials. The best known algorithm for computing the
lexicographical Gr\"obner basis is in $\widetilde{O}(d^{3n})$ arithmetic
operations where $n$ is the number of variables and $d$ is the maximal degree
of the equations in the input system. The notation $\widetilde{O}$ means that
we neglect polynomial factors in $n$. We show that this complexity can be
decreased to $\widetilde{O}(d^{\omega n})$ where $2 \leq \omega < 2.3727$ is
the exponent in the complexity of multiplying two dense matrices. Consequently,
when the input polynomial system is either generic or reaches the B\'ezout
bound, the complexity of solving a polynomial system is decreased from
$\widetilde{O}(D^3)$ to $\widetilde{O}(D^\omega)$ where $D$ is the number of
solutions of the system. To achieve this result we propose new algorithms which
rely on fast linear algebra. When the degree of the equations are bounded
uniformly by a constant we propose a deterministic algorithm. In the unbounded
case we present a Las Vegas algorithm.


title: Macroscopic models of collective motion and self-organization

abstract:
  In this paper, we review recent developments on the derivation and properties
of macroscopic models of collective motion and self-organization. The starting
point is a model of self-propelled particles interacting with its neighbors
through alignment. We successively derive a mean-field model and its
hydrodynamic limit. The resulting macroscopic model is the Self-Organized
Hydrodynamics (SOH). We review the available existence results and known
properties of the SOH model and discuss it in view of its possible extensions
to other kinds of collective motion.


title: Hot scalar radiation setting bounds on the curvature coupling parameter

abstract:
  This paper addresses the interplay between vacuum and thermal local averages
for massless scalar radiation near a plane wall of a large cavity where the
Dirichlet boundary condition is assumed to hold. The main result is that stable
thermodynamic equilibrium is possible only if the curvature coupling parameter
is restricted to a certain range. In more than three spacetime dimensions such
a range contains the conformal coupling, but it does not contain the minimal
coupling. Since this same range for possible values of the curvature coupling
parameter also applies to massive scalar radiation, it may be relevant in
settings where arbitrarily coupled scalar fields are present.


title: Hopf Semialgebras

abstract:
  In this paper, we introduce and investigate \emph{bisemialgebras}and\emph{\
Hopf semialgebras} over commutative semirings. We generalize to the
semialgebraic context several results on bialgebras and Hopf algebras over
rings including the main reconstruction theorems and the \emph{Fundamental
Theorem of Hopf Algebras}. We also provide a notion of \emph{quantum monoids}
as Hopf semialgebras which are neither commutative nor cocommutative; this
extends the Hopf algebraic notion of a quantum group. The generalization to the
semialgebraic context is neither trivial nor straightforward due to the
non-additive nature of the base category of Abelian monoids which is also
neither Puppe-exact nor homological and does not necessarily have enough
injectives.


title: Solid state physics of impact crater formation: further considerations

abstract:
  Impact craters exist on solid surface planets, their satellites and many
asteroids.The aim of this paper is to propose a theoretical expression for the
product $\rho r^{3} v_{1}^{2}$,where the three symbols denote the mass
density,radius and speed of the impactor. The expression is derived using well
known results of solid state physics,and it can be used in estimating
parameters of impactors which have led to formation of craters on various solid
bodies in the Solar System.


title:
Intrinsic spin-relaxation induced negative tunnel magnetoresistance in a
  single-molecule magnet

abstract:
  We investigate theoretically the effects of intrinsic spin-relaxation on the
spin-dependent transport through a single-molecule magnet (SMM), which is
weakly coupled to ferromagnetic leads. The tunnel magnetoresistance (TMR) is
obtained by means of the rate-equation approach including not only the
sequential but also the cotunneling processes. It is shown that the TMR is
strongly suppressed by the fast spin-relaxation in the sequential region and
can vary from a large positive to slight negative value in the cotunneling
region. Moreover, with an external magnetic field along the easy-axis of SMM, a
large negative TMR is found when the relaxation strength increases. Finally, in
the high bias voltage limit the TMR for the negative bias is slightly larger
than its characteristic value of the sequential region, however it can become
negative for the positive bias caused by the fast spin-relaxation.


title:
Accessing quantum nanoplasmonics in a hybrid quantum-dot metal
  nanosystem: Mollow triplet of a quantum dot near a metal nanoparticle

abstract:
  We present a theoretical study of the resonance fluorescence spectra of an
optically driven quantum dot placed near a single metal nanoparticle. The
metallic reservoir coupling is calculated for an 8-nm metal nanoparticle using
a time-convolutionless master equation approach where the exact photon
reservoir function is included using Green function theory. By exciting the
system coherently near the nanoparticle dipole mode, we show that the driven
Mollow spectrum becomes highly asymmetric due to internal coupling effects with
higher-order plasmons. We also highlight regimes of resonance squeezing and
broadening as well as spectral reshaping through light propagation. Our master
equation technique can be applied to any arbitrary material system, including
lossy inhomogeneous structures, where mode expansion techniques are known to
break down.


title:
Mixing of the low-lying three- and five-quark $\Omega$ states with
  negative parity

abstract:
  Mixing of the low-1/2^{-}$ and $3/2^{-}$ is investigated, employing an
instanton-induced quark-antiquark pair creation model, which precludes
transitions between $s^{3}$ and $s^{4}\bar{s}$ configurations. Models with
hyperfine interactions between quarks of three different kinds, namely,
one-gluon-exchange, Goldstone-boson-exchange (GBE) and an instanton-induced
interaction (INS) are called OGE, GBE and INS models, respectively. Numerical
results show that the instanton-induced pair creation causes strong mixing
between the three- and five-quark configurations with spin 3/2, and that this
mixing decreases the energy of the lowest spin 3/2 states in all three
different hyperfine interaction models to $\sim 1750\pm50$ MeV. On the other
hand, transition couplings between $s^3$ and $s^{3}q\bar{q}$ states with spin
1/2 caused by instanton-induced $q\bar{q}$ creation is very small and the
resulting mixing of three- and five-quark configurations in the OGE and INS
models is negligible, while the mixing of the spin 1/2 states in GBE model is
not, but effects of this mixing on energies of mixed states are also very
small. Accordingly, the lowest $\Omega$ states with negative parity in all
three hyperfine interactions models have spin 3/2.


title:
Discontinuous Galerkin method for fractional convection-diffusion
  equations

abstract:
  We propose a discontinuous Galerkin method for convection-subdiffusion
equations with a fractional operator of order $\alpha (1<\alpha<2)$ defined
through the fractional Laplacian. The fractional operator of order $\alpha$ is
expressed as a composite of first order derivatives and fractional integrals of
order $2-\alpha$, and the fractional convection-diffusion problem is expressed
as a system of low order differential/integral equations and a local
discontinuous Galerkin method scheme is derived for the equations. We prove
stability and optimal order of convergence O($h^{k+1}$) for subdiffusion, and
an order of convergence of ${\cal O}(h^{k+1/2})$ is established for the general
fractional convection-diffusion problem. The analysis is confirmed by numerical
examples.