title: Directed weak fibrations

abstract:
  In a previous paper [21] the author studied the homotopy lifting property in
the category dTop of directed spaces in the sense of M. Grandis [12], [13],
[14]. The present paper, which is a continuation of aforementioned article,
introduces and studies the directed weak homotopy property (dWCHP) and directed
weak fibrations, extending to the category dTop the well known Dold's (or weak)
- fibrations [6]. The dWCHP is characterized in several ways. Then the notion
of a directed fibre homotopy equivalence (dFHE) between directed weak
fibrations is studied. Some examples and counterexamples are given.


title: Scalable Generation of Scale-free Graphs

abstract:
  We explain how massive instances of scale-free graphs following the
Barabasi-Albert model can be generated very quickly in an embarrassingly
parallel way. This makes this popular model available for studying big data
graph problems. As a demonstration, we generated a Petaedge graph in less than
an hour.


title: A Streaming Algorithm for Crowdsourced Data Classification

abstract:
  We propose a streaming algorithm for the binary classification of data based
on crowdsourcing. The algorithm learns the competence of each labeller by
comparing her labels to those of other labellers on the same tasks and uses
this information to minimize the prediction error rate on each task. We provide
performance guarantees of our algorithm for a fixed population of independent
labellers. In particular, we show that our algorithm is optimal in the sense
that the cumulative regret compared to the optimal decision with known labeller
error probabilities is finite, independently of the number of tasks to label.
The complexity of the algorithm is linear in the number of labellers and the
number of tasks, up to some logarithmic factors. Numerical experiments
illustrate the performance of our algorithm compared to existing algorithms,
including simple majority voting and expectation-maximization algorithms, on
both synthetic and real datasets.


title: A version of scale calculus and the associated Fredholm theory

abstract:
  This article provides a version of scale calculus geared towards a notion of
(nonlinear) Fredholm maps between certain types of Frechet spaces, retaining as
many as possible of the properties Fredholm maps between Banach spaces enjoy,
and the existence of a constant rank theorem for such maps. It does so by
extending the notion of linear Fredholm maps from [HWZ14] and [Weh12] to a
setting where the Nash-Moser inverse function theorem can be applied and which
also encompasses the necessary examples such as the reparametrisation action
and (nonlinear) elliptic partial differential operators.


title:
Variational Inference for On-line Anomaly Detection in High-Dimensional
  Time Series

abstract:
  Approximate variational inference has shown to be a powerful tool for
modeling unknown complex probability distributions. Recent advances in the
field allow us to learn probabilistic models of sequences that actively exploit
spatial and temporal structure. We apply a Stochastic Recurrent Network (STORN)
to learn robot time series data. Our evaluation demonstrates that we can
robustly detect anomalies both off- and on-line.


title: Nodal Geometry, Heat Diffusion and Brownian Motion

abstract:
  We use tools from $n$-dimensional Brownian motion in conjunction with the
Feynman-Kac formulation of heat diffusion to study nodal geometry on a compact
Riemannian manifold $M$. On one hand we extend a theorem of Lieb and prove that
any nodal domain $\Omega_\lambda$ almost fully contains a ball of radius $\sim
\frac{1}{\sqrt{\lambda}}$. This also gives a slight refinement of a result by
Mangoubi, concerning the inradius of nodal domains (\cite{Man2}). On the other
hand, we also prove that no nodal domain can be contained in a reasonably thin
tubular neighbourhood of unions of finitely many surfaces inside $M$.


title:
Every timelike geodesic in anti--de Sitter spacetime is a circle of the
  same radius

abstract:
  We refine and analytically prove an old proposition due to Calabi and Markus
on the shape of timelike geodesics of anti--de Sitter space in the ambient flat
space. We prove that each timelike geodesic forms in the ambient space a circle
of the radius determined by $\Lambda$, lying on a Euclidean two--plane. Then we
outline an alternative proof for $AdS_4$. We also make a comment on the shape
of timelike geodesics in de Sitter space.


title: Multipath streaming: fundamental limits and efficient algorithms

abstract:
  We investigate streaming over multiple links. A file is split into small
units called chunks that may be requested on the various links according to
some policy, and received after some random delay. After a start-up time called
pre-buffering time, received chunks are played at a fixed speed. There is
starvation if the chunk to be played has not yet arrived. We provide lower
bounds (fundamental limits) on the starvation probability of any policy. We
further propose simple, order-optimal policies that require no feedback. For
general delay distributions, we provide tractable upper bounds for the
starvation probability of the proposed policies, allowing to select the
pre-buffering time appropriately. We specialize our results to: (i) links that
employ CSMA or opportunistic scheduling at the packet level, (ii) links shared
with a primary user (iii) links that use fair rate sharing at the flow level.
We consider a generic model so that our results give insight into the design
and performance of media streaming over (a) wired networks with several paths
between the source and destination, (b) wireless networks featuring spectrum
aggregation and (c) multi-homed wireless networks.


title:
Lower bounds on the redundancy in computations from random oracles via
  betting strategies with restricted wagers

abstract:
  The Ku\v{c}era-G\'acs theorem is a landmark result in algorithmic randomness
asserting that every real is computable from a Martin-L\"of random real. If the
computation of the first $n$ bits of a sequence requires $n+h(n)$ bits of the
random oracle, then $h$ is the redundancy of the computation. Ku\v{c}era
implicitly achieved redundancy $n\log n$ while G\'acs used a more elaborate
coding procedure which achieves redundancy $\sqrt{n}\log n$. A similar upper
bound is implicit in the later proof by Merkle and Mihailovi\'c. In this paper
we obtain strict optimal lower bounds on the redundancy in computations from
Martin-L\"of random oracles. We show that any nondecreasing computable function
$g$ such that $\sum_n 2^{-g(n)}=\infty$ is not a general upper bound on the
redundancy in computations from Martin-L\"of random oracles. In fact, there
exists a real $X$ such that the redundancy $g$ of any computation of $X$ from a
Martin-L\"of random oracle satisfies $\sum_n 2^{-g(n)}<\infty$. Moreover, the
class of such reals is comeager and includes a $\Delta^0_2$ real as well as all
weakly 2-generic reals. This excludes many slow growing functions such as $\log
n$ from bounding the redundancy in computations from random oracles for a large
class of reals. On the other hand it was recently shown that if $\sum_n
2^{-g(n)}<\infty$ then $g$ is a general upper bound for the redundancy in
computations of any real from some Martin-L\"of random oracle. Our results are
obtained as an application of a theory of effective betting strategies with
restricted wagers which we develop.


title:
Interaction-induced hopping phase in driven-dissipative coupled photonic
  microcavities

abstract:
  Bosons hopping across sites and interacting on-site are the essence of the
Bose-Hubbard model (BHM). Inspired by the success of BHM simulators with atoms
in optical lattices, proposals for implementing the BHM with photons in coupled
nonlinear cavities have emerged. Two coupled semiconductor microcavities
constitute a model system where the hopping, interaction, and decay of exciton
polaritons --- mixed light-matter quasiparticles --- can be engineered in
combination with site-selective coherent driving to implement the
driven-dissipative two-site optical BHM. Here we explore the interplay of
interference and nonlinearity in this system, in a regime where three distinct
density profiles can be observed under identical driving conditions. We
demonstrate how the phase acquired by polaritons hopping between cavities can
be controlled through effective polariton-polariton interactions. Our results
open new perspectives for synthesizing density-dependent gauge fields for
polaritons in two-dimensional multicavity systems.


title: Level-Confluence of 3-CTRSs in Isabelle/HOL

abstract:
  We present an Isabelle/HOL formalization of an earlier result by Suzuki,
Middeldorp, and Ida; namely that a certain class of conditional rewrite systems
is level-confluent. Our formalization is basically along the lines of the
original proof, from which we deviate mostly in the level of detail as well as
concerning some basic definitions.


title:
Energetics of synchronization in coupled oscillators rotating on
  circular trajectories

abstract:
  We derive a concise and general expression of the energy dissipation rate for
coupled oscillators rotating on circular trajectories by unifying the
nonequilibrium aspects with the nonlinear dynamics via stochastic
thermodynamics. In the framework of phase oscillator models, it is known that
the even and odd parts of the coupling function express the effect on
collective and relative dynamics, respectively. We reveal that the odd part
always decreases the dissipation upon synchronization, while the even part
yields a characteristic square-root change of the dissipation near the
bifurcation point whose sign depends on the specific system parameters. We
apply our theory to hydrodynamically coupled Stokes spheres rotating on
circular trajectories that can be interpreted as a simple model of
synchronization of coupled oscillators in a biophysical system. We show that
the coupled Stokes spheres gain the ability to do more work on the surrounding
fluid as the degree of phase synchronization increases.

categories: nlin.AO cond-mat.soft cond-mat.stat-mech physics.bio-ph


title:
Centrifugal photovoltaic and photogalvanic effects driven by structured
  light

abstract:
  Much efforts are devoted to material structuring in a quest to enhance the
photovoltaic effect. We show that structuring light in a way it transfers
orbital angular momentum to semiconductor-based rings results in a steady
charge accumulation at the outer boundaries that be utilized for the generation
of an open circuit voltage or a photogalvanic (bulk photovoltaic) type current.
This effect which stems both from structuring light and matter (confinement
potentials), can be magnified even at fixed moderate intensities, by increasing
the orbital angular momentum of light which strengthens the effective
centrifugal potential that repels the charge outwards. Based on a full
numerical time propagation of the carriers wave functions in the presence of
light pulses we demonstrate how the charge buildup leads to a useable voltage
or directed photocurrent whose amplitudes and directions are controllable by
the light pulse parameters.


title: Construction of functions with given cluster sets

abstract:
  In this paper we continue our research of functions on the boundary of their
domain and obtain some results on cluster sets of functions between topological
spaces. In particular, we prove that for a metrizable topological space $X$, a
dense subspace $Y$ of a metrizable compact space $\overline{Y}$, a closed
nowhere dense subset $L$ of $X$, an upper continuous compact-valued
multifunction ${\Phi:L\multimap \overline{Y}}$ and a set $D\subseteq X\setminus
L$ such that $L\subseteq \overline{D}$, there exists a function $f:D\to Y$ such
that the cluster set $\overline{f} (x)$ is equal to $\Phi (x)$ for any $x\in
L$.


title: The ImageNet Shuffle: Reorganized Pre-training for Video Event Detection

abstract:
  This paper strives for video event detection using a representation learned
from deep convolutional neural networks. Different from the leading approaches,
who all learn from the 1,000 classes defined in the ImageNet Large Scale Visual
Recognition Challenge, we investigate how to leverage the complete ImageNet
hierarchy for pre-training deep networks. To deal with the problems of
over-specific classes and classes with few images, we introduce a bottom-up and
top-down approach for reorganization of the ImageNet hierarchy based on all its
21,814 classes and more than 14 million images. Experiments on the TRECVID
Multimedia Event Detection 2013 and 2015 datasets show that video
representations derived from the layers of a deep neural network pre-trained
with our reorganized hierarchy i) improves over standard pre-training, ii) is
complementary among different reorganizations, iii) maintains the benefits of
fusion with other modalities, and iv) leads to state-of-the-art event detection
results. The reorganized hierarchies and their derived Caffe models are
publicly available at http://tinyurl.com/imagenetshuffle.


title: Submodular Learning and Covering with Response-Dependent Costs

abstract:
  We consider interactive learning and covering problems, in a setting where
actions may incur different costs, depending on the response to the action. We
propose a natural greedy algorithm for response-dependent costs. We bound the
approximation factor of this greedy algorithm in active learning settings as
well as in the general setting. We show that a different property of the cost
function controls the approximation factor in each of these scenarios. We
further show that in both settings, the approximation factor of this greedy
algorithm is near-optimal among all greedy algorithms. Experiments demonstrate
the advantages of the proposed algorithm in the response-dependent cost
setting.


title: Abundances and kinematics for ten anticentre open clusters

abstract:
  Open clusters are distributed all across the disk and are convenient tracers
of its properties. In particular, outer disk clusters bear a key role for the
investigation of the chemical evolution of the Galactic disk. The goal of this
study is to derive homogeneous elemental abundances for a sample of ten outer
disk OCs, and investigate possible links with disk structures such as the
Galactic Anticenter Stellar Structure. We analyse high-resolution spectra of
red giants, obtained from the HIRES@Keck and UVES@VLT archives. We derive
elemental abundances and stellar atmosphere parameters by means of the
classical equivalent width method. We also performed orbit integrations using
proper motions. The Fe abundances we derive trace a shallow negative radial
metallicity gradient of slope -0.027+/-0.007 dex.kpc-1 in the outer 12 kpc of
the disk. The [alpha/Fe] gradient appears flat, with a slope of 0.006+/-0.007
dex.kpc-1 . The two outermost clusters (Be 29 and Sau 1) appear to follow
elliptical orbits. Be 20 also exhibits a peculiar orbit with a large excursion
above the plane. The irregular orbits of the three most metal-poor clusters (of
which two are located at the edge of the Galactic disk), if confirmed by more
robust astrometric measurements such as those of the Gaia mission, are
compatible with an inside-out formation scenario for the Milky Way, in which
extragalactic material is accreted onto the outer disk. We cannot determine if
Be 20, Be 29,and Sau 1 are of extragalactic origin, as they may be old genuine
Galactic clusters whose orbits were perturbed by accretion events or minor
mergers in the past 5 Gyr, or they may be representants of the thick disk
population. The nature of these objects is intriguing and deserves further
investigations in the near future.


title: Spontaneous Spin Textures in Multiorbital Mott Systems

abstract:
  Spin textures in k-space arising from spin-orbit coupling in
non-centrosymmetric crystals find numerous applications in spintronics. We
present a mechanism that leads to appearance of k-space spin texture due to
spontaneous symmetry breaking driven by electronic correlations. Using
dynamical mean-field theory we show that doping a spin-triplet excitonic
insulator provides a means of creating new thermodynamic phases with unique
properties. The numerical results are interpreted using analytic calculations
within a generalized double-exchange framework.


title: Rational taxation in an open access fishery model

abstract:
  We consider a model of fishery management, where $n$ agents exploit a single
population with strictly concave continuously differentiable growth function of
Verhulst type. If the agent actions are coordinated and directed towards the
maximization of the discounted cooperative revenue, then the biomass stabilizes
at the level, defined by the well known "golden rule". We show that for
independent myopic harvesting agents such optimal (or $\varepsilon$-optimal)
cooperative behavior can be stimulated by the proportional tax, depending on
the resource stock, and equal to the marginal value function of the cooperative
problem. To implement this taxation scheme we prove that the mentioned value
function is strictly concave and continuously differentiable, although the
instantaneous individual revenues may be neither concave nor differentiable.


title:
The Coulomb-interaction-induced breaking of the Aufbau principle for
  hole charging of InGaAs/GaAs quantum dots

abstract:
  The so called "incomplete hole shell filling" phenomenon, that is the
breaking of the Aufbau principle was reported by D. Reuter et al., [Phys. Rev.
Lett. 94, 026808] in the hole charging spectra of quantum dot when results were
interpreted in context of s/p/d shell system - typical for electrons. We report
an example of inter-particle-interaction induced Aufbau principle violation
even if it is applied to one-particle Kohn-Luttinger eigenstates. We present a
k-dot-p/configuration-interaction study that concerns multiple holes confined
in InGaAs/GaAs self-assembled cylindrical quantum dot. Eigenenergies and
eigenvectors of up to six hole ground states were obtained - along with
corresponding one-hole orbital occupations - and discussed in context of the
Aufbau principle.
  PACS numbers: 73.21.La, 81.07.Ta, 71.70.Gm


title: Car Type Recognition with Deep Neural Networks

abstract:
  In this paper we study automatic recognition of cars of four types: Bus,
Truck, Van and Small car. For this problem we consider two data driven
frameworks: a deep neural network and a support vector machine using SIFT
features. The accuracy of the methods is validated with a database of over 6500
images, and the resulting prediction accuracy is over 97 %. This clearly
exceeds the accuracies of earlier studies that use manually engineered feature
extraction pipelines.


title:
Model study of the electron-phonon coupling in graphene; relative
  importance of intraband and interband scattering

abstract:
  The aim of this model study of the electron-phonon coupling in graphene was
to find out about the relative importance of the inter- and intraband
scattering and which phonon modes are the most active. This was achieved by
analyzing the electron-phonon matrix element of the carbon dimer in the unit
cell. We found that for the intra molecular orbital matrix elements the
longitudinal optical phonon mode is the active phonon mode. The matrix element
corresponding to sigma to sigma is greater than the matrix element for pi to pi
. The inter molecular orbital scattering pi to sigma is driven by the
out-of-plane acoustic phonon mode, while the out-of-plane optical mode does not
contribute for symmetry reasons. We found the unexpected result that the
magnitude of matrix element of the inter molecular orbital scattering pi to
sigmat exceeds the intra molecular orbital scattering pi to pi . These results
indicate that the in general not considered inter-band scattering has to be
taken into account when analyzing e.g. photo-hole lifetimes and the
electron-phonon coupling constant ?from photoemission data of graphene.


title: Measuring Object-Oriented Design Principles

abstract:
  The idea of automatizing the assessment of objectoriented design is not new.
Different approaches define and apply their own quality models, which are
composed of single metrics or combinations thereof, to operationalize software
design. However, single metrics are too fine-grained to identify core design
flaws and they cannot provide hints for making design improvements. In order to
deal with these weaknesses of metric-based models, rules-based approaches have
proven successful in the realm of source-code quality. Moreover, for developing
a well-designed software system, design principles play a key role, as they
define fundamental guidelines and help to avoid pitfalls. Therefore, this
thesis will enhance and complete a rule-based quality reference model for
operationalizing design principles and will provide a measuring tool that
implements these rules. The validation of the design quality model and the
measurement tool will be based on various industrial projects. Additionally,
quantitative and qualitative surveys will be conducted in order to get
validated results on the value of object-oriented design principles for
software development


title: Website-Targeted False Content Injection by Network Operators

abstract:
  It is known that some network operators inject false content into users'
network traffic. Yet all previous works that investigate this practice focus on
edge ISPs (Internet Service Providers), namely, those that provide Internet
access to end users. Edge ISPs that inject false content affect their customers
only. However, in this work we show that not only edge ISPs may inject false
content, but also core network operators. These operators can potentially alter
the traffic of \emph{all} Internet users who visit predetermined websites. We
expose this practice by inspecting a large amount of traffic originating from
several networks. Our study is based on the observation that the forged traffic
is injected in an out-of-band manner: the network operators do not update the
network packets in-path, but rather send the forged packets \emph{without}
dropping the legitimate ones. This creates a race between the forged and the
legitimate packets as they arrive to the end user. This race can be identified
and analyzed. Our analysis shows that the main purpose of content injection is
to increase the network operators' revenue by inserting advertisements to
websites. Nonetheless, surprisingly, we have also observed numerous cases of
injected malicious content. We publish representative samples of the injections
to facilitate continued analysis of this practice by the security community.


title:
Structural and magnetic properties of S = 3/2 chemically disordered
  perovskite Sr2TiMnO6

abstract:
  Single phase polycrystalline sample of perovskite Sr2TiMnO6 (STMO) has been
successfully synthesized via solid state reaction route. Its detailed
structural and physical properties have been studied using x-ray diffraction,
transmission electron microscopy, magnetization, specific heat, and dielectric
measurements. Rietveld analysis of the powder XRD data and transmission
electron microscopy studies confirm that STMO is not a double perovskite
structure with Fm-3m space group. But it is a disordered perovskite structure
with Pm-3m space group where Ti4+ and Mn4+ ions are randomly distributed at the
1b site. The dc magnetization (\c{hi}dc-vs-T) measurements in the temperature
range 2-300K reveals a single anomaly at ~13K with predominant long range
canted antiferromagnetic (AFM) ordering. The frequency invariant maxima at 13K
in the ac susceptibility (\c{hi}ac-vs-T) discards the spin-glass behaviour in
STMO. Despite the presence of sharp feature in M-T data, the specific heat data
(Cp-vs-T) shows only a broad hump around 13K, which has been attributed to the
magneto-structural ordering giving rise to canted AFM state in chemically
disorder STMO. Matching with the magnetic and specific heat anomaly, the
dielectric permittivity also shows a broad anomaly around 14K, indicating the
possible magneto-dielectric coupling in STMO.


title: Particle-Time Duality in the Kicked Ising Chain I: The Dual Operator

abstract:
  We demonstrate that the dynamics of kicked spin chains possess a remarkable
duality property. The trace of the unitary evolution operator for $N$ spins at
time $T$ is related to one of a non-unitary evolution operator for $T$ spins at
time $N$. We investigate the spectrum of this dual operator with a focus on the
different parameter regimes (chaotic, regular) of the spin chain. We present
applications of this duality relation to spectral statistics in an accompanying
paper.


title: Unattainable & attainable bounds for quantum sensors

abstract:
  In quantum metrology, it is widely believed that the quantum Cramer-Rao bound
is attainable bound while it is not true. In order to clarify this point, we
explain why the quantum Cramer-Rao bound cannot be attained geometrically. In
this manuscript, we investigate noiseless channel estimation under energy
constraint for states, using a physically reasonable error function, and
present the optimal state and the attainable bound. We propose the experimental
generation of the optimal states for enhanced metrology using squeezing
transformations. This makes the estimation of unitary channels physically
implementable, while existing unitary estimation protocols do not work


title: Cartan coherent configurations

abstract:
  The Cartan scheme $\cal X$ of a finite group $G$ with a $(B,N)$-pair is
defined to be the coherent configuration associated with the action of $G$ on
the right cosets of the Cartan subgroup $B\cap N$ by the right multiplications.
It is proved that if $G$ is a simple group of Lie type, then asymptotically,
the coherent configuration $\cal X$ is 2-separable, i.e., the array of
2-dimensional intersection numbers determines $\cal X$ up to isomorphism. It is
also proved that in this case, the base number of $\cal X$ equals 2. This
enables us to construct a polynomial-time algorithm for recognizing the Cartan
schemes when the rank of $G$ and order of the underlying field are sufficiently
large. One of the key points in the proof of the main results is a new
sufficient condition for an arbitrary homogeneous coherent configuration to be
2-separable.


title: Validity of the third law of thermodynamics for the Tsallis entropy

abstract:
  Bento \textit{et al.} [Phys. Rev. E 91, 022105 (2015)] recently stated that
the Tsallis entropy violates the third law of thermodynamics for $0 < q <1$ in
the sub-additive regime. We first show that the division between the regimes $q
< 1$ and $q > 1$ is already inherent in the fundamental incomplete structure of
the deformed logarithms and exponentials underlying the Tsallis entropy. Then,
we provide the complete deformed functions and show that the Tsallis entropy
conforms to the third law of thermodynamics for both super-additive $q < 1$ and
sub-additive $q > 1$ regimes. Finally, we remark that the Tsallis entropy does
not require the use of escort-averaging scheme once it is expressed in terms of
the complete deformed functions.


title: On weakly $n$-absorbing ideals of commutative rings

abstract:
  All rings are commutative with $1\neq0$. The purpose of this paper is to
investigate the concept of weakly $n$-absorbing ideals generalizing weakly
2-absorbing ideals. We prove that over a $u$-ring $R$ the Anderson-Badawi's
conjectures about $n$-absorbing ideals and the Badawi-Yousefian's question
about weakly 2-absorbing ideals hold.


title:
Spectral gap and exponential convergence to equilibrium for a
  multi-species Landau system

abstract:
  In this paper we prove new constructive coercivity estimates and convergence
to equilibrium for a spatially non-homogeneous system of Landau equations with
soft potentials. We show that the nonlinear collision operator conserves each
species' mass, total momentum, total energy and that the Boltzmann entropy is
nonincreasing along solutions of the system. The entropy decay vanishes if and
only if the Boltzmann distributions of the single species are Maxwellians with
the same momentum and energy. A linearization of the collision operator is
computed, which has the same conservation properties as its nonlinear
counterpart. We show that the linearized system dissipates a quadratic entropy,
and prove existence of spectral gap and exponential decay of the solution
towards the global equilibrium.


title: Thermodynamics of trajectories of open quantum systems, step by step

abstract:
  Thermodynamics of trajectories promises to make possible the thorough
analysis of the dynamical properties of an open quantum system, a sought-after
goal in modern physics. Unfortunately, calculation of the relevant quantities
presents severe challenges. Determining the large-deviation function that gives
access to the full counting statistics associated with a dynamical order
parameter is challenging, if not impossible, even for systems evolving in a
restricted Liouville space. Acting on the realisation that the salient features
of most dynamical systems are encoded in the first few moments of the counting
statistics, in this article we present a method that gives sequential access to
these moments. Our method allows for obtaining analytical result in several
cases, as we illustrate, and allows using large deviation theory to reinterpret
certain well-known results.


title: Efficiency analysis of double perturbed pairwise comparison matrices

abstract:
  Efficiency is a core concept of multi-objective optimization problems and
multi-attribute decision making. In the case of pairwise comparison matrices a
weight vector is called efficient if the approximations of the elements of the
pairwise comparison matrix made by the ratios of the weights cannot be improved
in any position without making it worse in some other position. A pairwise
comparison matrix is called double perturbed if it can be made consistent by
altering two elements and their reciprocals. The most frequently used weighting
method, the eigenvector method is analyzed in the paper, and it is shown that
it produces an efficient weight vector for double perturbed pairwise comparison
matrices.


title:
On the viability of quintessential inflationary models from
  observational data

abstract:
  Assuming that primordial density fluctuationas are nearly Gaussian, from a
frequentist viewpoint, the two-dimensional marginalized joint coincidence
contour in the plane $(n_s,r)$ (being $n_s$ the spectral index and $r$ the
ratio of tensor to scalar perturbations), without the presence of running is
usually used to test the viability of the inflationary models. The models that
provide, between $50$ and $60$ e-folds, a curve in that plane, which lies
outside the $95.5 \%$ C.L are ruled out. I will basically argue that the this
low number of e-folds is unjustified, and that models leading to a theoretical
value of the running different from zero must be checked with observational
data allowing the running. When both prescriptions are taken into account,
dealing in the context of quintessential inflation, i.e. when the potential is
a combination of an inflationary with a quintessential one that leads to a
deflationary regime, inflationary models such as the quartic or the Higgs
potential are allowed.


title: Experimental verification of multidimensional quantum steering

abstract:
  Quantum steering enables one party to communicate with another remote party
even if the sender is untrusted. Such characteristics of quantum systems not
only provide direct applications to quantum information science, but are also
conceptually important for distinguishing between quantum and classical
resources. While concrete illustrations of steering have been shown in several
experiments, quantum steering has not been certified for higher dimensional
systems. Here, we introduce a simple method to experimentally certify two
different kinds of quantum steering: Einstein-Podolsky-Rosen (EPR) steering and
single-system (SS) steering (i.e., temporal steering), for dimensionality (d)
up to d=16. The former reveals the steerability among bipartite systems,
whereas the latter manifests itself in single quantum objects. We use
multidimensional steering witnesses to verify EPR steering of
polarization-entangled pairs and SS steering of single photons. The ratios
between the measured witnesses and the maximum values achieved by classical
mimicries are observed to increase with $d$ for both EPR and SS steering. The
designed scenario offers a new method to study further the genuine multipartite
steering of large dimensionality and potential uses in quantum information
processing.


title:
Beyond the locally tree-like approximation for percolation on real
  networks

abstract:
  Theoretical attempts proposed so far to describe ordinary percolation
processes on real-world networks rely on the locally tree-like ansatz. Such an
approximation, however, holds only to a limited extent, as real graphs are
often characterized by high frequencies of short loops. We present here a
theoretical framework able to overcome such a limitation for the case of site
percolation. Our method is based on a message passing algorithm that discounts
redundant paths along triangles in the graph. We systematically test the
approach on 98 real-world graphs and on synthetic networks. We find excellent
accuracy in the prediction of the whole percolation diagram, with significant
improvement with respect to the prediction obtained under the locally tree-like
approximation. Residual discrepancies between theory and simulations do not
depend on clustering and can be attributed to the presence of loops longer than
three edges. We present also a method to account for clustering in bond
percolation, but the improvement with respect to the method based on the
tree-like approximation is much less apparent.


title:
Regular functions on spherical nilpotent orbits in complex symmetric
  pairs: classical non-Hermitian cases

abstract:
  Given a classical semisimple complex algebraic group G and a symmetric pair
(G, K) of non-Hermitian type, we study the closures of the spherical nilpotent
K-orbits in the isotropy representation of K. For all such orbit closures, we
study the normality and we describe the K-module structure of the ring of
regular functions of the normalizations.


title:
Impact of momentum anisotropy and turbulent chromo-fields on thermal
  particle production in quark-gluon plasma medium

abstract:
  Momentum anisotropy present during the hydrodynamic evolution of Quark-Gluon
Plasma (QGP) in RHIC may lead to chromo-Weibel instability and turbulent
chromo-fields.The dynamics of the quark and gluon momentum distributions in
this case is governed by an effective diffusive Vlasov equation (linearized).
The solution of this linearized transport equation for the modified momentum
distribution functions lead to the mathematical form of non-equilibrium
momentum distribution functions of quarks/antiquarks and gluons. The
modification to these distributions encode the physics of turbulent color
fields and momentum anisotropy. In the present manuscript, we employ these
distribution functions to to estimate thermal dilepton production rate in the
QGP medium. The production rate is seen to have appreciable sensitivity to the
strength of the anisotropy.


title:
On Approximations of the Curve Shortening Flow and of the Mean Curvature
  Flow based on the DeTurck trick

abstract:
  In this paper we discuss novel numerical schemes for the computation of the
curve shortening and mean curvature flows that are based on special
reparametrizations. The main idea is to use special solutions to the harmonic
map heat flow in order to reparametrize the equations of motion. This idea is
widely known from the Ricci flow as the DeTurck trick. By introducing a
variable time scale for the harmonic map heat flow, we obtain families of
numerical schemes for the reparametrized flows. For the curve shortening flow
this family unveils a surprising geometric connection between the numerical
schemes in [5] and [9]. For the mean curvature flow we obtain families of
schemes with good mesh properties similar to those in [3]. We prove error
estimates for the semi-discrete scheme of the curve shortening flow. The
behaviour of the fully-discrete schemes with respect to the redistribution of
mesh points is studied in numerical experiments. We also discuss possible
generalizations of our ideas to other extrinsic flows.


title: Quantum metrology enhanced by repetitive quantum error correction

abstract:
  The accumulation of quantum phase in response to a signal is the central
mechanism of quantum sensing, as such, loss of phase information presents a
fundamental limitation. For this reason approaches to extend quantum coherence
in the presence of noise are actively being explored. Here we experimentally
protect a room-temperature hybrid spin register against environmental
decoherence by performing repeated quantum error correction whilst maintaining
sensitivity to signal fields. We use a long-lived nuclear spin to correct
multiple phase errors on a sensitive electron spin in diamond and realize
magnetic field sensing beyond the timescales set by natural decoherence. The
universal extension of sensing time, robust to noise at any frequency,
demonstrates the definitive advantage entangled multi-qubit systems provide for
quantum sensing and offers an important complement to quantum control
techniques. In particular, our work opens the door for detecting minute signals
in the presence of high frequency noise, where standard protocols reach their
limits.


title:
Constrained lattice-field hierarchies and Toda system with Block
  symmetry

abstract:
  In this paper, we construct the additional $W$-symmetry and ghost symmetry of
two-lattice field integrable hierarchies. Using the symmetry constraint, we
construct constrained two-lattice integrable systems which contain several new
integrable difference equations. Under a further reduction, the constrained
two-lattice integrable systems can be combined into one single integrable
system, namely the well-known one dimensional original Toda hierarchy. We prove
that the one dimensional original Toda hierarchy has a nice Block Lie symmetry.


title: Variabilitatea structurala a padurii naturale. Studiu de caz: Calimani

abstract:
  The paper presents the importance of research which characterizes the natural
forest structure for the forest management. The lessons learned in these
particular forest ecosystems can be integrated by the forest management
objectives, in order to increase the sustainability of this type of resources.
The project NATFORMAN was focused on the structure of the natural forest, thus
research methodologies and modern technology (such as Field-Map) investigation
and determination were used in order to record information on forest structural
parameters. The results obtained refer to these structural parameters and to
the possibility of transferring such information in practice, in order to
achieve forest sustainable management.


title: Limits of Mappings

abstract:
  In this paper we consider a simple algebraic structure --- sets with a single
endofunction. We shall see that from the point of view of limits, even this
simplest case is both interesting and difficult. Nevertheless we obtain the
shape of limit objects in the full generality, and we prove the inverse theorem
in the easiest case of quantifier-free limits.


title: A textbook example of ram-pressure stripping in the Hydra A/A780 cluster

abstract:
  In the current epoch, one of the main mechanisms driving the growth of galaxy
clusters is the continuous accretion of group-scale halos. In this process, the
ram pressure applied by the hot intracluster medium on the gas content of the
infalling group is responsible for stripping the gas from its dark-matter halo,
which gradually leads to the virialization of the infalling gas in the
potential well of the main cluster. Using deep wide-field observations of the
poor cluster Hydra A/A780 with XMM-Newton and Suzaku, we report the discovery
of an infalling galaxy group 1.1 Mpc south of the cluster core. The presence of
a substructure is confirmed by a dynamical study of the galaxies in this
region. A wake of stripped gas is trailing behind the group over a projected
scale of 760 kpc. The temperature of the gas along the wake is constant at kT ~
1.3 keV, which is about a factor of two less than the temperature of the
surrounding plasma. We observe a cold front pointing westwards compared to the
peak of the group, which indicates that the group is currently not moving in
the direction of the main cluster, but is moving along an almost circular
orbit. The overall morphology of the group bears remarkable similarities with
high-resolution numerical simulations of such structures, which greatly
strengthens our understanding of the ram-pressure stripping process.


title: Passivity-Based Output-Feedback Control of Turbulent Channel Flow

abstract:
  This paper describes a robust linear time-invariant output-feedback control
strategy to reduce turbulent fluctuations, and therefore skin-friction drag, in
wall-bounded turbulent fluid flows, that nonetheless gives performance
guarantees in the nonlinear turbulent regime. The novel strategy is effective
in reducing the supply of available energy to feed the turbulent fluctuations,
expressed as reducing a bound on the supply rate to a quadratic storage
function. The nonlinearity present in the equations that govern the dynamics of
the flow is known to be passive and can be considered as a feedback forcing to
the linearised dynamics (a Lur'e decomposition). Therefore, one is only
required to control the linear dynamics in order to make the system close to
passive. The ten most energy-producing spatial modes of a turbulent channel
flow were identified. Passivity-based controllers were then generated to
control these modes. The controllers require measurements of streamwise and
spanwise wall-shear stress, and they actuate via wall transpiration. Nonlinear
direct numerical simulations demonstrated that these controllers were capable
of significantly reducing the turbulent energy and skin-friction drag of the
flow.


title:
Topological phase transitions with SO(4) symmetry in (2+1)d interacting
  Dirac fermions

abstract:
  Interaction-driven topological phase transitions in Dirac semimetals are
investigated by means of large-scale quantum Monte Carlo (QMC) simulations. The
interaction among Dirac fermions is introduced by coupling them to Ising spins
that realize the quantum dynamics of the two-dimensional transverse field Ising
model. The ground state phase diagram, in which the tuning parameters are the
transverse field and the coupling between fermion and Ising spins, is
determined. At weak and intermediate coupling, a second-order Ising quantum
phase transition and a first-order topological phase transition between two
topologically distinct Dirac semimetals are observed. Interestingly, at the
latter, the Dirac points smear out to form nodal lines in the Brillouin zone,
and collective bosonic fluctuations with SO(4) symmetry are strongly enhanced.
At strong coupling, these two phase boundaries merge into a first-order
transition.


title:
Flow in a Circular Expansion Pipe Flow: Effect of a Vortex Perturbation
  on Localized Turbulence

abstract:
  We report the results of three-dimensional direct numerical simulations for
incompressible viscous fluid in a circular pipe flow with a sudden expansion.
At the inlet, a parabolic velocity profile is applied together with a finite
amplitude perturbation in the form of a vortex with its axis parallel to the
axis of the pipe. At sufficiently high Reynolds numbers the recirculation
region breaks into a turbulent patch that changes position axially depending on
the strength of the perturbation. This vortex perturbation is believed to
produce a less abrupt transition than in previous studies with a tilt
perturbation, as the localized turbulence is observed via the formation of a
wavy structure at a low order azimuthal mode, which resembles an optimally
amplified perturbation. For higher amplitude, the localized turbulence remains
at a constant axial position. It is further investigated using proper
orthogonal decomposition, which indicates that the centre region close to the
expansion is highly energetic.


title:
Measurement of the Z gamma to nu nu-bar gamma production cross section
  in pp collisions at sqrt(s) = 8 TeV and limits on anomalous Z-Z-gamma and
  Z-gamma-gamma trilinear gauge boson couplings

abstract:
  A measurement of the Z gamma to nu nu-bar gamma production cross section in
pp collisions at sqrt(s) = 8 TeV is presented, using data corresponding to an
integrated luminosity of 19.6 inverse femtobarns collected with the CMS
detector at the LHC. This measurement is based on the observation of events
with large missing energy and with a single photon with transverse momentum
above 145 GeV and absolute pseudorapidity in the range |eta| < 1.44. The
measured Z gamma to nu nu-bar gamma production cross section, 52.7 +/-
2.1(stat) +/- 6.4 (syst) +/- 1.4 (lumi) fb, agrees well with the standard model
prediction of 50.0 +2.4 -2.2 fb. A study of the photon transverse momentum
spectrum yields the most stringent limits to date on the anomalous Z-Z-gamma
and Z-gamma-gamma trilinear gauge boson couplings.


title:
Prediction of transits of solar system objects in Kepler/K2 images: An
  extension of the Virtual Observatory service SkyBoT

abstract:
  All the fields of the extended space mission Kepler/K2 are located within the
ecliptic. Many solar system objects thus cross the K2 stellar masks on a
regular basis. We aim at providing to the entire community a simple tool to
search and identify solar system objects serendipitously observed by Kepler.
The SkyBoT service hosted at IMCCE provides a Virtual Observatory (VO)
compliant cone-search that lists all solar system objects present within a
field of view at a given epoch. To generate such a list in a timely manner,
ephemerides are pre-computed, updated weekly, and stored in a relational
database to ensure a fast access. The SkyBoT Web service can now be used with
Kepler. Solar system objects within a small (few arcminutes) field of view are
identified and listed in less than 10 sec. Generating object data for the
entire K2 field of view (14{\deg}) takes about a minute. This extension of the
SkyBot service opens new possibilities with respect to mining K2 data for solar
system science, as well as removing solar system objects from stellar
photometric time-series.


title: On the Power of Advice and Randomization for Online Bipartite Matching

abstract:
  While randomized online algorithms have access to a sequence of uniform
random bits, deterministic online algorithms with advice have access to a
sequence of advice bits, i.e., bits that are set by an all powerful oracle
prior to the processing of the request sequence. Advice bits are at least as
helpful as random bits, but how helpful are they? In this work, we investigate
the power of advice bits and random bits for online maximum bipartite matching
(MBM).
  The well-known Karp-Vazirani-Vazirani algorithm is an optimal randomized
$(1-\frac{1}{e})$-competitive algorithm for \textsc{MBM} that requires access
to $\Theta(n \log n)$ uniform random bits. We show that
$\Omega(\log(\frac{1}{\epsilon}) n)$ advice bits are necessary and
$O(\frac{1}{\epsilon^5} n)$ sufficient in order to obtain a
$(1-\epsilon)$-competitive deterministic advice algorithm. Furthermore, for a
large natural class of deterministic advice algorithms, we prove that
$\Omega(\log \log \log n)$ advice bits are required in order to improve on the
$\frac{1}{2}$-competitiveness of the best deterministic online algorithm, while
it is known that $O(\log n)$ bits are sufficient.
  Last, we give a randomized online algorithm that uses $c n$ random bits, for
integers $c \ge 1$, and a competitive ratio that approaches $1-\frac{1}{e}$
very quickly as $c$ is increasing. For example if $c = 10$, then the difference
between $1-\frac{1}{e}$ and the achieved competitive ratio is less than
$0.0002$.


title:
Extreme current fluctuations of boundary-driven systems in the large-N
  limit

abstract:
  Current fluctuations in boundary-driven diffusive systems are, in many cases,
studied using hydrodynamic theories. Their predictions are then expected to be
valid for currents which scale inversely with the system size. To study this
question in detail, we introduce a class of large-N models of one-dimensional
boundary-driven diffusive systems, whose current large deviation functions are
exactly derivable for any finite number of sites. Surprisingly, we find that
for some systems the predictions of the hydrodynamic theory may hold well
beyond their naive regime of validity. Specifically, we show that, while a
symmetric partial exclusion process exhibits non-hydrodynamic behaviors
sufficiently far beyond the naive hydrodynamic regime, a symmetric inclusion
process is well described by the hydrodynamic theory for arbitrarily large
currents. We conjecture, and verify for zero-range processes, that the
hydrodynamic theory captures the statistics of arbitrarily large currents for
all models where the mobility coefficient as a function of density is unbounded
from above. In addition, for the large-N models, we prove the additivity
principle under the assumption that the large deviation function has no
discontinuous transitions.


title:
Gauge transformation and symmetries of the commutative multi-component
  BKP hierarchy

abstract:
  In this paper, we defined a new multi-component BKP hierarchy which takes
values in a commutative subalgebra of $gl(N,\mathbb C)$. After this, we give
the gauge transformation of this commutative multi-component BKP (CMBKP)
hierarchy. Meanwhile we construct a new constrained CMBKP hierarchy which
contains some new integrable systems including coupled KdV equations under a
certain reduction. After this, the quantum torus symmetry and quantum torus
constraint on the tau function of the commutative multi-component BKP hierarchy
will be constructed.


title:
Multi-fold Darboux transformations of the extended bigraded Toda
  hierarchy

abstract:
  With the extended logarithmic flow equations and some extended Vertex
operators in generalized Hirota bilinear equations, extended bigraded Toda
hierarchy(EBTH) was proved to govern the Gromov-Witten theory of orbiford
$c_{NM}$ in literature. The generating function of these Gromov-Witten
invariants is one special solution of the EBTH. In this paper, the multi-fold
Darboux transformations and their determinant representations of the EBTH are
given with two different gauge transformation operators. The two Darboux
transformations in different directions are used to generate new solutions from
known solutions which include soliton solutions of $(N,N)$-EBTH, i.e. the EBTH
when $N=M$. From the generation of new solutions, one can find the big
difference between the EBTH and the extended Toda hierarchy(ETH). Meanwhile we
plotted the soliton graphs of the $(N,N)$-EBTH from which some approximation
analysis will be given. From the analysis on velocities of soliton solutions,
the difference between the extended flows and other flows are shown. The two
different Darboux transformations constructed by us might be useful in
Gromov-Witten theory of orbiford $c_{NM}$.


title: On the infimum of certain functionals

abstract:
  In this note, in particular, we establish the following result: Let $X$ be a
real Banach space, $\varphi\in X^*\setminus \{0\}$ and $\psi:X\to {\bf R}$ a
Lipschitzian functional with Lipschitz constant equal to $\varphi\|_X^{*}$.
Then, we have $$\max\left\{\inf_{x\in X}(\varphi(x)+\psi(x)),\inf_{x\in
X}(\varphi(x)-\psi(x))\right\}=\inf_{x\in X}(\varphi(x)+|\psi(x)|)$$ and
$$\liminf_{\|x\|\to +\infty}(\varphi(x)+|\psi(x)|)=\inf_{x\in
X}(\varphi(x)+|\psi(x)|)\ .$$


title:
A transition from a decelerated to an accelerated phase of the universe
  expansion from the simplest non-trivial polynomial function of T in the
  f(R,T) formalism

abstract:
  In this work we present cosmological solutions from the simplest non-trivial
$T$-dependence in $f(R,T)$ theory of gravity, with $R$ and $T$ standing for the
Ricci scalar and trace of the energy-momentum tensor, respectively. Although
such an approach yields a highly non-linear differential equation for the scale
factor, we show that it is possible to obtain analytical solutions for the
cosmological parameters. For some values of the free parameters, the model is
able to predict a transition from a decelerated to an accelerated expansion of
the universe.


title: The role of symmetry in the interpretation of quantum mechanics

abstract:
  Despite the impressive amount of literature on the foundations of quantum
mechanics, the relevance of symmetry in interpretation is not properly
acknowledged. In fact, although it is usually said that quantum mechanics is
invariant under the Galilean group, the invariance is usually not discussed in
the case of the interpretation of the theory. This situation is particularly
pressing for realist positions, which want to know how reality would be if
quantum mechanics were true. From a realist perspective, it seems reasonable to
require that an interpretation of quantum mechanics, to be admissible,
preserves the same symmetries of the theory. In this paper we will take a
realist standpoint in order to study what physical constraints the Galilean
group imposes on interpretation, and we will extrapolate the conclusions drawn
for quantum mechanics to the case of quantum field theory.


title:
Nonlocal correlations and spectral properties of the Falicov-Kimball
  model

abstract:
  We derive an analytical expression for the local two-particle vertex of the
Falicov-Kimball model, including its dependence on all three frequencies, the
full vertex and all reducible vertices. This allows us to calculate the self
energy in diagrammatic extensions of dynamical mean field theory, specifically
in the dual fermion and the one-particle irreducible approach. Non-local
correlations are thence included and originate here from charge density wave
fluctuations. At low temperatures and in two dimensions, they lead to a larger
self energy contribution at low frequencies and a more insulating spectrum.


title: Abelian varieties over finite fields as basic abelian varieties

abstract:
  In this note we show that any basic abelian variety with additional
structures over an arbitrary algebraically closed field of characteristic $p>0$
is isogenous to another one defined over a finite field. We also show that the
category of abelian varieties over finite fields up to isogeny can be embedded
into the category of basic abelian varieties with suitable endomorphism
structures. Using this connection, we derive a new mass formula for a finite
orbit of polarized abelian surfaces over a finite field.


title: On two conjectures about the proper connection number of graphs

abstract:
  A path in an edge-colored graph is called proper if no two consecutive edges
of the path receive the same color. For a connected graph $G$, the proper
connection number $pc(G)$ of $G$ is defined as the minimum number of colors
needed to color its edges so that every pair of distinct vertices of $G$ are
connected by at least one proper path in $G$. In this paper, we consider two
conjectures on the proper connection number of graphs. The first conjecture
states that if $G$ is a noncomplete graph with connectivity $\kappa(G) = 2$ and
minimum degree $\delta(G)\ge 3$, then $pc(G) = 2$, posed by Borozan et al.~in
[Discrete Math. 312(2012), 2550-2560]. We give a family of counterexamples to
disprove this conjecture. However, from a result of Thomassen it follows that
3-edge-connected noncomplete graphs have proper connection number 2. Using this
result, we can prove that if $G$ is a 2-connected noncomplete graph with
$diam(G)=3$, then $pc(G) = 2$, which solves the second conjecture we want to
mention, posed by Li and Magnant in [Theory \& Appl. Graphs 0(1)(2015), Art.2].


title: Addition formulae of discrete KP, q-KP and two-component BKP systems

abstract:
  In this paper, we constructed the addition formulae for several integrable
hierarchies, including the discrete KP, the q-deformed KP, the two-component
BKP and the D type Drinfeld-Sokolov hierarchies. With the help of the Hirota
bilinear equations and $\tau$ functions of different kinds of KP hierarchies,
we prove that these addition formulae are equivalent to these hierarchies.
These studies show that the addition formula in the research of the integrable
systems has good universality.


title: Corrections to A Menagerie of Timed Automata

abstract:
  This note corrects a technical error in the ACM Computing Surveys paper
mentioned in the title. The flaw involved constructions for showing that timed
automata with urgent locations have the same expressiveness as timed automata
that allow false location invariants. Corrected con- structions are presented
in this note, and the affected results are reproved.


title:
A Rotating-Frame Perspective on High-Harmonic Generation of Circularly
  Polarized Light

abstract:
  We employ a rotating frame of reference to elucidate high-harmonic generation
of circularly polarized light by bicircular driving fields. In particular, we
show how the experimentally observed circular components of the high-harmonic
spectrum can be directly related to the corresponding quantities in the
rotating frame. Supported by numerical simulations of the time-dependent
Schr\"{o}dinger equation, we deduce an optimal strategy for maximizing the
cutoff in the high-harmonic plateau while keeping the two circular components
of the emitted light spectrally distinct. Moreover, we show how the
rotating-frame picture can be more generally employed for elliptical drivers.
Finally, we point out how circular and elliptical driving fields show a
near-duality to static electric and static magnetic fields in a rotating-frame
description. This demonstrates how high-harmonic generation of circularly
polarized light under static electromagnetic fields can be emulated in practice
even at static field strengths beyond current experimental capabilities.


title: The intersection ring of matroids

abstract:
  We study a particular graded ring structure on the set of all loopfree
matroids on a fixed labeled ground set, which occurs naturally in tropical
geometry. The product is given by matroid intersection and the additive
structure is defined by assigning to each matroid the indicator vector of its
chains of flats. We show that this ring is generated in corank one, more
precisely that any matroid can be written as a linear combination of products
of corank one matroids. Moreover, we prove that a basis for the graded part of
rank r matroids is given by the set of nested matroids and that the total
number of these is a Eulerian number. Derksen's G-invariant then defines a
Z-linear map on this ring, which implies for example that the Tutte polynomial
is linear on it as well. Finally we show that the ring is the cohomology ring
of the toric variety of the permutohedron and thus fulfills Poincar\'e duality.


title: ZeroDB white paper

abstract:
  ZeroDB is an end-to-end encrypted database that enables clients to operate on
(search, sort, query, and share) encrypted data without exposing encryption
keys or cleartext data to the database server. The familiar client-server
architecture is unchanged, but query logic and encryption keys are pushed
client-side. Since the server has no insight into the nature of the data, the
risk of data being exposed via a server-side data breach is eliminated. Even if
the server is successfully infiltrated, adversaries would not have access to
the cleartext data and cannot derive anything useful out of disk or RAM
snapshots.
  ZeroDB provides end-to-end encryption while maintaining much of the
functionality expected of a modern database, such as full-text search, sort,
and range queries. Additionally, ZeroDB uses proxy re-encryption and/or delta
key technology to enable secure, granular sharing of encrypted data without
exposing keys to the server and without sharing the same encryption key between
users of the database.


title:
Modal analysis of gravitational instabilities in nearly Keplerian,
  counter-rotating collisionless discs

abstract:
  We present a modal analysis of instabilities of counter-rotating,
self-gravitating collisionless stellar discs, using the recently introduced
modified WKB formulation of spiral density waves for collisionless systems
(Gulati \& Saini). The discs are assumed to be axisymmetric and in coplanar
orbits around a massive object at the common center of the discs. The mass in
both discs is assumed to be much smaller than the mass of the central object.
For each disc, the disc particles are assumed to be in near circular orbits.
The two discs are coupled to each other gravitationally. The perturbed dynamics
of the discs evolves on the order of the precession time scale of the discs,
which is much longer than the Keplerian time scale. We present results for the
azimuthal wave number $m=1$ and $m=2$, for the full range of disc mass ratio
between the prograde and retrograde discs. The eigenspectra are in general
complex, therefore all eigenmodes are unstable. Eigenfunctions are radially
more compact for $m = 1$ as compared to $m = 2$. Pattern speed of eigenmodes is
always prograde with respect to the more massive disc. The growth rate of
unstable modes increases with increasing mass fraction in the retrograde disc,
and decreases with $m$; therefore $m=1$ instability is likely to play the
dominant role in the dynamics of such systems.


title: Dissortativity and duplications in Oral cancer

abstract:
  More than 300,000 new cases worldwide are being diagnosed with oral cancer
annually. Complexity of oral cancer renders designing drug targets very
difficult. We analyse protein-protein interaction network for the normal and
oral cancer tissue and detect crucial changes in the structural properties of
the networks in terms of the interactions of the hub proteins and the
degree-degree correlations. Further analysis of the spectra of both the
networks, while exhibiting universal statistical behavior, manifest distinction
in terms of the zero degeneracy, providing insight to the complexity of the
underlying system.


title: Improved bounds for hypohamiltonian graphs

abstract:
  A graph $G$ is hypohamiltonian if $G$ is non-hamiltonian and $G - v$ is
hamiltonian for every $v \in V(G)$. In the following, every graph is assumed to
be hypohamiltonian. Aldred, Wormald, and McKay gave a list of all graphs of
order at most 17. In this article, we present an algorithm to generate all
graphs of a given order and apply it to prove that there exist exactly 14
graphs of order 18 and 34 graphs of order 19. We also extend their results in
the cubic case. Furthermore, we show that (i) the smallest graph of girth 6 has
order 25, (ii) the smallest planar graph has order at least 23, (iii) the
smallest cubic planar graph has order at least 54, and (iv) the smallest cubic
planar graph of girth 5 with non-trivial automorphism group has order 78.


title:
Preparation of Silver and Silver-backing self-supported thin targets by
  high vacuum evaporation

abstract:
  We have produced in the Nuclear Physics Center in Lisbon thin film
self-supported targets of Ag, LiF/Ag and CaF$_2$/Ag by a high vacuum resistance
evaporation method. The production setup, materials, methods, characterization
and results are described.


title:
Frequency Redistribution of Polarized Light in the Lambda-Type
  Multi-Term Polarized Atom

abstract:
  We study the effects of Rayleigh and Raman scattering on the formation of
polarized spectral lines in a $\Lambda$-type multi-term atom. We fully take
into account the partial redistribution of frequency and the presence of atomic
polarization in the lower states of the atomic model. Problems that can be
modeled with this formalism include, for example, the formation of the Ca II
H-K and IR triplet, the analogous system of Ba II, and the Ly$\beta$-H$\alpha$
system of hydrogenic ions.


title:
Dwell time modulation restrictions do not necessarily improve treatment
  plan quality for prostate HDR brachytherapy

abstract:
  Inverse planning algorithms for dwell time optimisation in interstitial
high-dose-rate (HDR) brachytherapy may produce solutions with large dwell time
variations within catheters, which may result in undesirable selective
high-dose subvolumes. Extending the optimisation model with a dwell time
modulation restriction (DTMR) that limits dwell time differences between
neighboring dwell positions has been suggested to eliminate this issue. DTMRs
may additionally reduce the sensitivity for uncertainties in dwell positions
that result from catheter reconstruction errors and source positioning
inaccuracies. This study quantifies the reduction of high-dose subvolumes and
the robustness against these uncertainties by applying a DTMR to template-based
prostate HDR brachytherapy implants.
  Three different DTMRs were consecutively applied to a linear dose-based
penalty model (LD) and a dose-volume based model (LDV), both obtained from
literature. The models were solved with DTMR levels ranging from no restriction
to uniform dwell times within catheters. Uncertainties were simulated on
clinical cases using in-house developed software, and dose-volume metrics were
calculated in each simulation. For the assessment of high-dose subvolumes, the
dose homogeneity index (DHI) and the contiguous dose volume histogram were
analysed. Robustness was measured by the improvement of the lowest $D_{90\%}$
of the planning target volume (PTV) observed in the simulations.
  For (LD), a DTMR yields an increase in DHI of 30% and reduces the size of the
largest high-dose volume by 2 to 5 cc. This came at a cost of a reduction in
$D_{90\%}$ of the PTV of 10%, which often implies that it drops below the
desired minimum of 100%. For (LDV), none of the DTMRs improved high-dose volume
measures. DTMRs were not capable of improving robustness of PTV $D_{90\%}$
against uncertainty in dwell positions for both models.


title: Cluster Assembly in Hierarchically Collapsing Clouds

abstract:
  We discuss the mechanism of cluster formation in hierarchically collapsing
molecular clouds. Recent evidence, both observational and numerical, suggests
that molecular clouds (MCs) may be undergoing global, hierarchical
gravitational collapse. The "hierarchical" regime consists of small-scale
collapses within larger-scale ones. The latter implies that the star formation
rate increases systematically during the early stages of evolution, and occurs
via filamentary flows onto "hubs" of higher density, mass, and velocity
dispersion, and culminates a few Myr after than the small-scale collapses have
started to form stars. In turn, the small-scale collapses occur in clumps
embedded in the filaments, and are themselves falling into the larger potential
well of the still-ongoing large-scale collapse. The stars formed in the early,
small-scale collapses share the infall motion of their parent clumps towards
the larger potential trough, so that the filaments feed both gaseous and
stellar material to the hubs. This leads to the presence of older stars in a
region where new protostars are still forming, to a scale-free or fractal
structure of the clusters, in which each unit is composed of smaller-scale
ones, and to the eventual merging of the subunits, explaining the observed
structural features of open clusters.


title:
Null controllability for a heat equation with a singular inverse-square
  potential involving the distance to the boundary function

abstract:
  This article is devoted to the analysis of control properties for a heat
equation with singular potential $\mu/\delta^2$, defined on a bounded $C^2$
domain $\Omega\subset\mathbb{R}^N$, where $\delta$ is the distance to the
boundary function. More precisely, we show that for any $\mu\leq 1/4$ the
system is exactly null controllable using a distributed control located in any
open subset of $\Omega$, while for $\mu>1/4$ there is no way of preventing the
solutions of the equation from blowing-up. The result is obtained applying a
new Carleman estimate.


title: Gravity and On-Shell Probe Actions

abstract:
  In any gravitational theory and in a wide class of background space-times, we
argue that there exists a simple, yet profound, relation between the on-shell
Euclidean gravitational action and the on-shell Euclidean action of probes. The
probes can be, for instance, charged particles or branes. The relation is
tightly related to the thermodynamic nature of gravity. We provide precise
checks of the relation in several examples, which include both asymptotically
flat and asymptotically AdS space-times, with particle, D-brane and M-brane
probes. Perfect consistency is found in all cases, including in a highly
non-trivial example including \alpha'-corrections.


title: Massive fermion model in 3d and higher spin currents

abstract:
  We analyze the 3d free massive fermion theory coupled to external sources.
The presence of a mass explicitly breaks parity invariance. We calculate two-
and three-point functions of a gauge current and the energy momentum tensor
and, for instance, obtain the well-known result that in the IR limit (but also
in the UV one) we reconstruct the relevant CS action. We then couple the model
to higher spin currents and explicitly work out the spin 3 case. In the UV
limit we obtain an effective action which was proposed many years ago as a
possible generalization of spin 3 CS action. In the IR limit we derive a
different higher spin action. This analysis can evidently be generalized to
higher spins. We also discuss the conservation and properties of the
correlators we obtain in the intermediate steps of our derivation.


title: Curvature-driven migration of colloids on lipid bilayers

abstract:
  Colloids and proteins alike can bind to lipid bilayers and move laterally in
these two-dimensional fluids. Inspired by proteins that generate membrane
curvature, sense the underlying membrane geometry, and migrate to high
curvature sites, we explore the question: Can colloids, adhered to lipid
bilayers, also sense and respond to membrane geometry? We report the curvature
migration of Janus microparticles adhered to giant unilamellar vesicles
elongated to present well defined curvature fields. However, unlike proteins,
which migrate to minimize membrane bending energy, colloids migrate by an
entirely different mechanism. By determining the energy dissipated along a
trajectory, the energy field mediating these interactions is inferred to be
linear in the local deviatoric curvature, as reported previously for colloids
trapped at curved interfaces between immiscible fluids. In this latter system,
however, the energy gradients are far larger, so particles move
deterministically, whereas the colloids on vesicles move with significant
fluctuations in regions of weak curvature gradient. By addressing the role of
Brownian motion, we show that the observed curvature migration of colloids on
bilayers is indeed a case of curvature capillary migration, with membrane
tension playing the role of interfacial tension. Furthermore, since this motion
is mediated by membrane tension and shape, it can be modulated, or even turned
"on" and "off", by simply varying these parameters. While particle-particle
interactions on lipid membranes have been considered in many contributions, we
report here an exciting and previously unexplored modality to actively direct
the migration of colloids to desired locations on lipid bilayers.


title: Les lois Z\^eta pour l'arithm\'etique

abstract:
  This paper provides a probabilist point of view about some results in
analytic number theory. The main tool is the family of Zeta laws, which is a
consolation for the non-existence of an uniform law on the set of integers. We
prove the existence and compute the natural density for the pairs of coprime
integers, and also for the pairs of coprime Gaussian integers.Along the way, we
recover the decomposition of the Zeta function as an Eulerian product and some
related results.


title: 3D-Printing for Analytical Ultracentrifugation

abstract:
  Analytical ultracentrifugation (AUC) is a classical technique of physical
biochemistry providing information on size, shape, and interactions of
macromolecules from the analysis of their migration in centrifugal fields while
free in solution. A key mechanical element in AUC is the centerpiece, a
component of the sample cell assembly that is mounted between the optical
windows to allow imaging and to seal the sample solution column against high
vacuum while exposed to gravitational forces in excess of 300,000 g. For
sedimentation velocity it needs to be precisely sector-shaped to allow
unimpeded radial macromolecular migration. During the history of AUC a great
variety of centerpiece designs have been developed for different types of
experiments. Here, we report that centerpieces can now be readily fabricated by
3D printing at low cost, from a variety of materials, and with customized
designs. The new centerpieces can exhibit sufficient mechanical stability to
withstand the gravitational forces at the highest rotor speeds and be
sufficiently precise for sedimentation equilibrium and sedimentation velocity
experiments. Sedimentation velocity experiments with bovine serum albumin as a
reference molecule in 3D printed centerpieces with standard double-sector
design result in sedimentation boundaries virtually indistinguishable from
those in commercial double-sector epoxy centerpieces, with sedimentation
coefficients well within the range of published values. The statistical error
of the measurement is slightly above that obtained with commercial epoxy, but
still below 1%. Facilitated by modern open-source design and fabrication
paradigms, we believe 3D printed centerpieces and AUC accessories can spawn a
variety of improvements in AUC experimental design, efficiency and resource
allocation.


title: Explore First, Exploit Next: The True Shape of Regret in Bandit Problems

abstract:
  We revisit lower bounds on the regret in the case of multi-armed bandit
problems. We obtain non-asymptotic, distribution-dependent bounds and provide
straightforward proofs based only on well-known properties of Kullback-Leibler
divergences. These bounds show in particular that in an initial phase the
regret grows almost linearly, and that the well-known logarithmic growth of the
regret only holds in a final phase. The proof techniques come to the essence of
the information-theoretic arguments used and they are deprived of all
unnecessary complications.


title:
Re-refinement of 4xan: hen egg white lysozyme with carboplatin in sodium
  bromide solution including details of solute, solvent, ion and split
  occupancy amino acid electron density evidence

abstract:
  A re-refinement of 4xan, hen egg white lysozyme (HEWL) with carboplatin
crystallised in NaBr solution, has been made (Tanley et al 2016). This follows
our Response article (Tanley et al 2015) to the Critique article of Shabalin et
al 2015, suggesting the need for corrections to some solute molecule
interpretations of electron density in 4xan and removal of an organic moiety as
a ligand to the platinum ion coordinated to His15. We note Shabalin et al
(2015) model of a chlorine in that density and a close by bromine at partial
occupancy to explain the shape. However, as the bromide concentration is in
huge excess over chloride (by 20 fold), we think that the 4yem Shabalin et al
2015 interpretation highly unlikely, but nevertheless we still cannot offer an
explanation for that shape, confirming our earlier analysis described in Tanley
et al (2014). Following Shabalin et al (2015) reprocessing of the raw
diffraction data for 4g4a, we also redid the diffraction data processing for
4xan to a higher resolution using EVAL (Schreurs et al 2010) concluding in
favour of 1.3 Angstrom as the resolution limit and which is the basis for our
revised PDB file for 4xan (5HMJ). It is very interesting that there is extra
X-ray diffraction data from 1.47 to 1.30 Angstrom resolution e.g. with
<I/sigma(I)> =0.39 and CC1/2 = 0.181 in the final shell (1.30 to 1.322
Angstrom). In this arXiv article we document in detail our different solvent
and split occupancy side chain electron density interpretations as evidence for
our statement of approach in our Response article (Tanley et al 2015). Our
critical re-examination includes comparisons based on the 4xan diffraction data
images reprocessing with three different software packages so as to evaluate
the possibility of variations in electron density interpretations due to that.
Overall our finalised model (PDB code 5HMJ) is now improved over 4xan.


title: The symmetric signature

abstract:
  We define two related invariants for a $d$-dimensional local ring
$(R,\mathfrak{m},k)$ called syzygy and differential symmetric signature by
looking at the maximal free splitting of reflexive symmetric powers of two
modules: the top dimensional syzygy module $\mathrm{Syz}^d_R(k)$ of the residue
field and the module of K\"ahler differentials $\Omega_{R/k}$ of $R$ over $k$.
We compute these invariants for two-dimensional ADE singularities obtaining
$1/|G|$, where $|G|$ is the order of the acting group, and for cones over
elliptic curves obtaining $0$ for the differential symmetric signature. These
values coincide with the F-signature of such rings in positive characteristic.


title: Crowdsourcing Health Labels: Inferring Body Weight from Profile Pictures

abstract:
  To use social media for health-related analysis, one key step is the
detection of health-related labels for users. But unlike transient conditions
like flu, social media users are less vocal about chronic conditions such as
obesity, as users might not tweet "I'm still overweight". As, however,
obesity-related conditions such as diabetes, heart disease, osteoarthritis, and
even cancer are on the rise, this obese-or-not label could be one of the most
useful for studies in public health.
  In this paper we investigate the feasibility of using profile pictures to
infer if a user is overweight or not. We show that this is indeed possible and
further show that the fraction of labeled-as-overweight users is higher in U.S.
counties with higher obesity rates. Going from public to individual health
analysis, we then find differences both in behavior and social networks, for
example finding users labeled as overweight to have fewer followers.


title:
Internal wave attractors examined using laboratory experiments and 3D
  numerical simulations

abstract:
  In the present paper, we combine numerical and experimental approaches to
study the dynamics of stable and unstable internal wave attractors. The problem
is considered in a classic trapezoidal setup filled with a uniformly stratified
fluid. Energy is injected into the system at global scale by the
small-amplitude motion of a vertical wall. Wave motion in the test tank is
measured with the help of conventional synthetic schlieren and PIV techniques.
The numerical setup closely reproduces the experimental one in terms of
geometry and the operational range of the Reynolds and Schmidt numbers. The
spectral element method is used as a numerical tool to simulate the nonlinear
dynamics of a viscous salt-stratified fluid. We show that the results of
three-dimensional calculations are in excellent qualitative and quantitative
agreement with the experimental data, including the spatial and temporal
parameters of the secondary waves produced by triadic resonance instability.
Further, we explore experimentally and numerically the effect of lateral walls
on secondary currents and spanwise distribution of velocity amplitudes in the
wave beams. Finally, we test the assumption of a bidimensional flow and
estimate the error made in synthetic schlieren measurements due to this
assumption.


title: Essential dimension of group schemes over a local scheme

abstract:
  In this paper we develop the theory of essential dimension of group schemes
over an integral base. Shortly we concentrate over a local base. As a
consequence of our theory we give a result of invariance of the essential
dimension over a field. The case of group schemes over a discrete valuation
ring is discussed. Moreover we propose a generalization of Ledet conjecture,
which predicts the essential dimension of cyclic $p$-groups in positive
characteristic, for finite commutative unipotent group schemes. And we show
some results and some consequences of this new conjecture.


title: Exploring the Neural Algorithm of Artistic Style

abstract:
  We explore the method of style transfer presented in the article "A Neural
Algorithm of Artistic Style" by Leon A. Gatys, Alexander S. Ecker and Matthias
Bethge (arXiv:1508.06576).
  We first demonstrate the power of the suggested style space on a few
examples. We then vary different hyper-parameters and program properties that
were not discussed in the original paper, among which are the recognition
network used, starting point of the gradient descent and different ways to
partition style and content layers. We also give a brief comparison of some of
the existing algorithm implementations and deep learning frameworks used.
  To study the style space further we attempt to generate synthetic images by
maximizing a single entry in one of the Gram matrices $\mathcal{G}_l$ and some
interesting results are observed. Next, we try to mimic the sparsity and
intensity distribution of Gram matrices obtained from a real painting and
generate more complex textures.
  Finally, we propose two new style representations built on top of network's
features and discuss how one could be used to achieve local and potentially
content-aware style transfer.


title: New Generalizations of Cosmography Inspired by the Pade Approximant

abstract:
  The current accelerated expansion of the universe has been one of the most
important fields in physics and astronomy since 1998. Many cosmological models
have been proposed in the literature to explain this mysterious phenomenon.
Since the nature and cause of the cosmic acceleration are still unknown,
model-independent approaches to study the evolution of the universe are
welcome. One of the powerful model-independent approaches is the so-called
cosmography. It only relies on the cosmological principle, without postulating
any underlying theoretical model. However, there are several shortcomings in
the usual cosmography. For instance, it is plagued with the problem of
divergence (or an unacceptably large error), and it fails to predict the future
evolution of the universe. In the present work, we try to overcome or at least
alleviate these problems, and we propose two new generalizations of cosmography
inspired by the Pad\'e approximant. One is to directly parameterize the
luminosity distance based on the Pad\'e approximant, while the other is to
generalize cosmography with respect to a so-called $y_\beta$-shift
$y_\beta=z/(1+\beta z)$, which is also inspired by the Pad\'e approximant.
Then, we confront them with the observational data with the help of the Markov
chain Monte Carlo (MCMC) code emcee, and find that they work fairly well.


title: Propagation of radiation pulses through gas-plasma mixtures

abstract:
  We determine the linear optical susceptibility of a radiation pulse
propagating through a mixture of a gas of atoms or molecules and a plasma. For
a specific range of radiation and plasma frequencies, resonant generation of
volume plasmons significantly amplifies the radiation intensity. The conditions
for resonant amplification are derived from the dispersion relations in the
mixture, and the amplification is demonstrated in a numerical simulation of
pulse propagation.


title:
A unified field theory II: Gravity interacting with a Yang-Mills and
  Higgs field

abstract:
  We quantize the interaction of gravity with a Yang-Mills and Higgs field
using canonical quantization. Similar to the approach in a previous paper we
discard the Wheeler-DeWitt equation and express the Hamilton constraint by the
evolution equation of the mean curvature of the hypersurfaces in the foliation
defined by the Hamiltonian setting. Expressing the time derivative of the mean
curvature with the help of the Poisson brackets the canonical quantization of
this equation leads to a wave equation in $Q=(0,\infty)\times \cal{S}_o$, where
$\cal{S}_o$ is one of the Cauchy hypersurfaces in the Hamiltonian setting. The
wave equation describes the interaction of an arbitrary Riemannian metric in
$\cal{S}_o$ and a given Yang-Mills and Higgs field. If the metric is complete
$Q$ is globally hyperbolic. In case $\cal{S}_o$ is compact we also prove a
spectral resolution of the wave equation and establish sufficient conditions
guaranteeing a mass gap.


title:
Transformations between Jordan and Einstein frames: Bounces,
  antigravity, and crossing singularities

abstract:
  We study the relation between the Jordan-Einstein frame transition and the
possible description of the crossing of singularities in flat Friedmann
universes, using the fact that the regular evolution in one frame can
correspond to crossing singularities in the other frame. We show that some
interesting effects arise in simple models such as one with a massless scalar
field or another wherein the potential is constant in the Einstein frame. The
dynamics in these models and in their conformally coupled counterparts are
described in detail, and a method for the continuation of such cosmological
evolutions beyond the singularity is developed. We compare our approach with
some other, recently developed, approaches to the problem of the crossing of
singularities.


title: Isotropic stars in higher-order torsion scalar theories

abstract:
  Two tetrad spaces reproducing spherically symmetric spacetime are applied to
the equations of motion of higher-order torsion theories. Assuming the
existence of conformal Killing vector, two isotropic solutions are derived. We
show that the first solution is not stable while the second one confirms a
stable behavior. We also discuss the construction of the stellar model and show
that one of our solution capable of such construction while the other cannot.
Finally, we discuss the generalized Tolman-Oppenheimer-Volkoff and show that
one of our models has a tendency to equilibrium.


title:
Lens depth function and k-relative neighborhood graph: versatile tools
  for ordinal data analysis

abstract:
  In recent years it has become popular to study machine learning problems in a
setting of ordinal distance information rather than numerical distance
measurements. By ordinal distance information we refer to binary answers to
distance comparisons such as $d(A,B)<d(C,D)$. For many problems in machine
learning and statistics it is unclear how to solve them in such a scenario. Up
to now, the main approach is to explicitly construct an ordinal embedding of
the data points in the Euclidean space, an approach that has a number of
drawbacks. In this paper, we propose algorithms for the problems of medoid
estimation, outlier identification, classification, and clustering when given
only ordinal data. They are based on estimating the lens depth function and the
$k$-relative neighborhood graph on a data set. Our algorithms are simple, are
much faster than an ordinal embedding approach and avoid some of its drawbacks,
and can easily be parallelized.


title: Paging with Multiple Caches

abstract:
  Modern content delivery networks consist of one or more back-end servers
which store the entire content catalog, assisted by multiple front-end servers
with limited storage and service capacities located near the end-users.
Appropriate replication of content on the front-end servers is key to maximize
the fraction of requests served by the front-end servers. Motivated by this, a
multiple cache variant of the classical single cache paging problem is studied,
which is referred to as the Multiple Cache Paging (MCP) problem. In each
time-slot, a batch of content requests arrive that have to be served by a bank
of caches, and each cache can serve exactly one request. If a content is not
found in the bank, it is fetched from the back-end server, and one currently
stored content is ejected, and counted as fault. As in the classical paging
problem, the goal is to minimize the total number of faults. The competitive
ratio of any online algorithm for the MCP problem is shown to be unbounded for
arbitrary input, thus concluding that the MCP problem is fundamentally
different from the classical paging problem. Consequently, stochastic arrivals
setting is considered, where requests arrive according to a known/unknown
stochastic process. It is shown that near optimal performance can be achieved
with simple policies that require no co-ordination across the caches.


title: Entanglement breaking channels and entanglement sudden death

abstract:
  The occurrence of entanglement sudden death in the evolution of a bipartite
system depends on both the initial state and the channel responsible for the
evolution. An extreme case is that of entanglement braking channels, which are
channels that acting on only one of the subsystems drives them to full
disentanglement regardless of the initial state. In general, one can find
certain combinations of initial states and channels acting on one or both
subsystems that can result in entanglement sudden death or not. Neither the
channel nor the initial state, but their combination, is responsible for this
effect, but their combination. In this work we show that, in all cases, when
entanglement sudden death occurs, the evolution can be mapped to that of an
effective entanglement breaking channel on a modified initial state. Our
results allow to anticipate which states will suffer entanglement sudden death
or not for a given evolution. An experiment with polarization entangled photons
demonstrates the utility of this result in a variety of cases.


title: Massive Gauge-flation

abstract:
  Gauge-flation model at zeroth order in cosmological perturbation theory
offers an interesting scenario for realizing inflation within a particle
physics context, allowing us to investigate interesting possible connections
between inflation and the subsequent evolution of the Universe. Difficulties,
however, arise at the perturbative level, thus motivating a modification of the
original model. In order to agree with the latest Planck observations, we
modify the model such that the new dynamics can produce a relation between the
spectral index $n_{s}$ and the tensor-to-scalar ratio $r$ allowed by the data.
By including an identical mass term for each of the fields of the system, we
find interesting dynamics leading to slow-roll inflation of the right length.
The presence of the mass term has the potential to modify the $n_{s}$ vs. $r$
relation so as to agree with the data. As a first step, we study the model at
zeroth order in cosmological perturbation theory, finding the conditions
required for slow-roll inflation and the number of e-foldings of inflation.
Numerical solutions are used to explore the impact of the mass term. We
conclude that the massive version of Gauge-flation offers a viable inflationary
model.


title:
Gravitational collapse of cylindrical anisotropic fluid: A source of
  gravitational waves

abstract:
  The present work deals with dynamics of gravitational collapse with
cylindrical symmetry as developed by Misner and Sharp. The interior collapsing
anisotropic cylindrical perfect fluid is matched to an exterior vacuum
cylindrically symmetric space-time due to Einstein--Rosen using the Darmois
matching conditions. It is found that the radial pressure of the anisotropic
perfect fluid is non-zero on the boundary surface and is related to the
components of shear viscosity. As a result, there is formation of gravitational
waves outside the collapsing matter.


title: Human-Machine Networks: Towards a Typology and Profiling Framework

abstract:
  In this paper we outline an initial typology and framework for the purpose of
profiling human-machine networks, that is, collective structures where humans
and machines interact to produce synergistic effects. Profiling a human-machine
network along the dimensions of the typology is intended to facilitate access
to relevant design knowledge and experience. In this way the profiling of an
envisioned or existing human-machine network will both facilitate relevant
design discussions and, more importantly, serve to identify the network type.
We present experiences and results from two case trials: a crisis management
system and a peer-to-peer reselling network. Based on the lessons learnt from
the case trials we suggest potential benefits and challenges, and point out
needed future work.


title:
Solvable Leibniz algebra with non-Lie and non-split naturally graded
  filiform nilradical and its rigidity

abstract:
  The description of complex solvable Leibniz algebras whose nilradical is a
naturally graded filiform algebra is already known. Unfortunately, a mistake
was made in that description. Namely, in the case where the dimension of the
solvable Leibniz algebra with nilradical $F_n^1$ is equal to $n+2$, it was
asserted that there is no such algebra. However, it was possible for us to find
a unique $(n+2)$-dimensional solvable Leibniz algebra with nilradical $F_n^1$.
In addition, we establish the triviality of the second group of cohomology for
this algebra with coefficients in itself, which implies its rigidity.


title:
Large deviations principle for biorthogonal ensembles and variational
  formulation for the Dykema-Haagerup distribution

abstract:
  This note provides a large deviations principle for a class of biorthogonal
ensembles. We extend the results of Eichelsbacher, Sommerauer and Stotlz to
more general type of interactions. Our result covers the case of the singular
values of lower triangular random matrices with independent entries introduced
by Cheliotis. In particular, we obtain as a consequence a variational
formulation for the Dykema-Haagerup as it is the limit law for the singular
values of lower triangular matrices with i.i.d. complex Gaussian entries.


title:
Gaussian continuum basis functions for calculating high-harmonic
  generation spectra

abstract:
  We explore the computation of high-harmonic generation spectra by means of
Gaussian basis sets in approaches propagating the time-dependent
Schr{\"o}dinger equation. We investigate the efficiency of Gaussian functions
specifically designed for the description of the continuum proposed by Kaufmann
et al. [J. Phys. B 22, 2223 (1989)]. We assess the range of applicability of
this approach by studying the hydrogen atom, i.e. the simplest atom for which
"exact" calculations on a grid can be performed. We notably study the effect of
increasing the basis set cardinal number, the number of diffuse basis
functions, and the number of Gaussian pseudo-continuum basis functions for
various laser parameters. Our results show that the latter significantly
improve the description of the low-lying continuum states, and provide a
satisfactory agreement with grid calculationsfor laser wavelengths $\lambda$0 =
800 and 1064 nm. The Kaufmann continuum functions therefore appear as a
promising way of constructing Gaussian basis sets for studying molecular
electron dynamics in strong laser fields using time-dependent quantum-chemistry
approaches.


title:
Classical link invariants from the framizations of the Iwahori-Hecke
  algebra and the Temperley-Lieb algebra of type $A$

abstract:
  In this paper we first present the construction of the new 2-variable
classical link invariants arising from the Yokonuma-Hecke algebras ${\rm
Y}_{d,n}(q)$, which are not topologically equivalent to the Homflypt
polynomial. We then present the algebra ${\rm FTL}_{d,n}(q)$ which is the
appropriate Temperley-Lieb analogue of ${\rm Y}_{d,n}(q)$, as well as the
related 1-variable classical link invariants, which in turn are not
topologically equivalent to the Jones polynomial. Finally, we present the
algebra of braids and ties which is related to the Yokonuma-Hecke algebra, and
also its quotient, the partition Temperley-Lieb algebra ${\rm PTL}_n(q)$ and we
prove an isomorphism of this algebra with a subalgebra of ${\rm FTL}_{d,n}(q)$.


title:
Photovoltaic response around a unique180{\textdegree} ferroelectric
  domain wall in single crystalline BiFeO3

abstract:
  Using an experimental setup designed to scan a submicron sized light spot and
collect the photogenerated current through larger electrodes, we map the
photovoltaic response in ferroelectric BiFeO3 single crystals. We study the
effect produced by a unique 180{\textdegree} ferroelectric domain wall (DW) and
show that the photocurrent maps are significantly affected by its presence and
shape. The effect is large in its vicinity and in the Schottky barriers at the
interface with the Au electrodes, but no extra photocurrent is observed when
the illuminating spot touches the DW, indicating that this particular entity is
not the heart of specific photo-electric properties. Using 3D modelling, we
argue that the measured effect is due to the spatial distribution of internal
fields which are significantly affected by the charge of the DW due to its
distortion.


title:
Diffusive approximation of a time-fractional Burger's equation in
  nonlinear acoustics

abstract:
  A fractional time derivative is introduced into the Burger's equation to
model losses of nonlinear waves. This term amounts to a time convolution
product, which greatly penalizes the numerical modeling. A diffusive
representation of the fractional derivative is adopted here, replacing this
nonlocal operator by a continuum of memory variables that satisfy local-in-time
ordinary differential equations. Then a quadrature formula yields a system of
local partial differential equations, well-suited to numerical integration. The
determination of the quadrature coefficients is crucial to ensure both the
well-posedness of the system and the computational efficiency of the diffusive
approximation. For this purpose, optimization with constraint is shown to be a
very efficient strategy. Strang splitting is used to solve successively the
hyperbolic part by a shock-capturing scheme, and the diffusive part exactly.
Numerical experiments are proposed to assess the efficiency of the numerical
modeling, and to illustrate the effect of the fractional attenuation on the
wave propagation.