title:
Charge transfer, confinement, and ferromagnetism in LaMnO$_3$/LaNiO$_3$
  (001)-superlattice

abstract:
  Using first-principles density functional theory calculations, we
investigated the electronic structure and magnetic properties of
(LaMnO$_3$)$_m$/(LaNiO$_3$)$_n$ superlattices stacked along (001)-direction.
The electrons are transferred from Mn to Ni, and the magnetic moments are
induced at Ni sites that are paramagnetic in bulk and other types of
superlattices. The size of induced moment is linearly proportional to the
amount of transferred electrons, but it is larger than the net charge transfer
because the spin and orbital directions play important roles and complicate the
transfer process. The charge transfer and magnetic properties of the ($m$,$n$)
superlattice can be controlled by changing the $m/n$ ratio. Considering the
ferromagnetic couplings between Mn and Ni spins and the charge transfer
characteristic, we propose the (2,1) superlattice as the largest moment
superlattice carrying $\sim8\mu_B$ per formula unit.


title:
Individual departure time decision considering departure scheduling
  utility

abstract:
  The scheduling utility plays a fundamental role in addressing the commuting
travel behaviours. In this paper, a new scheduling utility, termed as DMRD-SU,
was suggested based on some recent research findings in behavioural economics.
DMRD-SU admitted the existence of positive arrival-caused utility. In addition,
besides the travel-time-caused utility and arrival-caused utility, DMRD-SU
firstly took the departure utility into account. The necessity of the departure
utility in trip scheduling was analysed comprehensively, and the corresponding
individual trip scheduling model was presented. Based on a simple network, an
analytical example was executed to characterize DMRD-SU. It can be found from
the analytical example that: 1) DMRD-SU can predict the accumulation departure
behaviors at NDT, which explains the formation of daily serious
short-peak-hours in reality, while MRD-SU cannot; 2) compared with MRD-SU,
DMRD-SU predicts that people tend to depart later and its gross utility also
decrease faster. Therefore, the departure utility should be considered to
describe the traveler's scheduling behaviors better.


title:
Density Functional Theory of a Curved Liquid-Vapour Interface:
  Evaluation of the rigidity constants

abstract:
  It is argued that to arrive at a quantitative description of the surface
tension of a liquid drop as a function of its inverse radius, it is necessary
to include the bending rigidity k and Gaussian rigidity k_bar in its
description. New formulas for k and k_bar in the context of density functional
theory with a non-local, integral expression for the interaction between
molecules are presented. These expressions are used to investigate the
influence of the choice of Gibbs dividing surface and it is shown that for a
one-component system, the equimolar surface has a special status in the sense
that both k and k_bar are then the least sensitive to a change in the location
of the dividing surface. Furthermore, the equimolar value for k corresponds to
its maximum value and the equimolar value for k_bar corresponds to its minimum
value. An explicit evaluation using a short-ranged interaction potential
between molecules, shows that k is negative with a value around minus 0.5-1.0
kT and that k_bar is positive with a value which is a bit more than half the
magnitude of k. Finally, for dispersion forces between molecules, we show that
a term proportional to log(R)/R^2 replaces the rigidity constants and we
determine the (universal) proportionality constants.


title: Eta-nuclear bound states revisited

abstract:
  The strong energy dependence of the s-wave eta-N scattering amplitude at and
below threshold, as evident in coupled-channels K-matrix fits and chiral models
that incorporate the S11 N*(1535) resonance, is included self-consistently in
eta-nuclear bound-state calculations. This approach, applied recently in
calculations of kaonic atoms and Kbar-nuclear bound states, is found to impose
stronger constraints than ever on the onset of eta-nuclear binding, with a
minimum value of Re a_{eta N} approximately 0.9 fm required to accommodate an
eta-4He bound state. Binding energies and widths of eta-nuclear states are
calculated within several underlying eta-N models for nuclei across the
periodic table, including eta-25Mg for which some evidence was proposed in a
recent COSY experiment.


title:
The ASTRI Project: a mini-array of dual-mirror small Cherenkov
  telescopes for CTA

abstract:
  ASTRI is a flagship project of the Italian Ministry of Education, University
and Research, which aims to develop an end-to-end prototype of the CTA
small-size telescope. The proposed design is characterized by a dual-mirror
Schwarzschild-Couder configuration and a camera based on Silicon
photo-multipliers, two challenging but innovative technological solutions which
will be adopted for the first time on a Cherenkov telescope. Here we describe
the current status of the project, the expected performance and the possibility
to realize a mini-array composed by a few small-size telescopes, which shall be
placed at the final CTA Southern Site.


title: Bounds on fifth forces from precision measurements on molecules

abstract:
  Highly accurate results from frequency measurements on neutral hydrogen
molecules H_2, HD and D_2 as well as the HD^+ ion can be interpreted in terms
of constraints on possible fifth-force interactions. Where the hydrogen atom is
a probe for yet unknown lepton-hadron interactions, and the helium atom is
sensitive for lepton-lepton interactions, molecules open the domain to search
for additional long-range hadron-hadron forces. First principles calculations
in the framework of quantum electrodynamics have now advanced to the level that
hydrogen molecules and hydrogen molecular ions have become calculable systems,
making them a search-ground for fifth forces. Following a phenomenological
treatment of unknown hadron-hadron interactions written in terms of a Yukawa
potential of the form V_5(r)=\beta exp(-r/\lambda)/r current precision
measurements on hydrogenic molecules yield a constraint \beta < 1 \times
10^{-7} eV\AA for long-range hadron-hadron interactions at typical force ranges
commensurate with separations of a chemical bond, i.e. \lambda ~1 \AA and
beyond.


title: The Gauss-Bonnet-Chern mass for graphic manifolds

abstract:
  In this paper, we prove a positive mass theorem and Penrose-type inequality
of the Gauss-Bonnet-Chern mass $m_2$ for the graphic manifold with flat normal
bundle.


title: A simple proof of monotonicity for linear cooperative systems of ODEs

abstract:
  We present a simple proof of monotonicity for cooperative systems of linear
ordinary differential equations, without having recourse to approximation by
strongly cooperative systems.


title: Intersecting integer partitions

abstract:
  If $a_1, a_2, ..., a_k$ and $n$ are positive integers such that $n = a_1 +
a_2 + ... + a_k$, then the sum $a_1 + a_2 + ... + a_k$ is said to be a
\emph{partition of $n$} of \emph{length $k$}, and $a_1, a_2, ..., a_k$ are said
to be the \emph{parts} of the partition. Two partitions that differ only in the
order of their parts are considered to be the same. We say that two partitions
\emph{intersect} if they have at least one common part. We call a set $A$ of
partitions \emph{intersecting} if any two partitions in $A$ intersect. Let
$P_{n,k}$ be the set of all partitions of $n$ of length $k$. We conjecture that
if $2 \leq k \leq n$, then the size of any intersecting subset of $P_{n,k}$ is
at most the size of $P_{n-1,k-1}$, which is the size of the intersecting subset
of $P_{n,k}$ consisting of those partitions which have 1 as a part. The
conjecture is trivially true for $n \leq 2k$, and we prove it for $n \geq
5k^5$. We also generalise this for subsets of $P_{n,k}$ with the property that
any two of their members have at least $t$ common parts.


title: Weighted skewness and kurtosis unbiased by sample size

abstract:
  Central moments and cumulants are often employed to characterize the
distribution of data. The skewness and kurtosis are particularly useful for the
detection of outliers, the assessment of departures from normally distributed
data, automated classification techniques and other applications. Robust
definitions of higher order moments are more stable but might miss
characteristic features of the data, as in the case of astronomical time series
with rare events like stellar bursts or eclipses from binary systems. Weighting
can help identify reliable measurements from uncertain or spurious outliers, so
unbiased estimates of the weighted skewness and kurtosis moments and cumulants,
corrected for sample-size biases, are provided under the assumption of
independent data. The comparison of biased and unbiased weighted estimators is
illustrated with simulations as a function of sample size, employing different
data distributions and weighting schemes.


title: Simulating Structure Formation of the Local Universe

abstract:
  In this work we present cosmological N-body simulations of the Local Universe
with initial conditions constrained by the Two-Micron Redshift Survey (2MRS)
within a cubic volume of 180 Mpc/h side-length centred at the Local Group. We
use a self-consistent Bayesian based approach to explore the joint parameter
space of primordial density fluctuations and peculiar velocity fields, which
are compatible with the 2MRS galaxy distribution after cosmic evolution. This
method (the KIGEN-code) includes the novel ALPT (Augmented Lagrangian
Perturbation Theory) structure formation model which combines second order LPT
(2LPT) on large scales with the spherical collapse model on small scales.
Furthermore we describe coherent flows with 2LPT and include a dispersion term
to model fingers-of-god (fogs). These implementations are crucial to avoid
artificial filamentary structures, which appear when using a structure
formation model with 2LPT and data with compressed fogs. We assume LCDM
cosmology throughout our method. The recovered initial Gaussian fields are used
to perform a set of 25 constrained simulations. Statistically this ensemble of
simulations is in agreement with a reference set of 25 simulations based on
randomly seeded Gaussian fluctuations in terms of matter statistics,
power-spectra and mass functions. Considering the entire volume, we obtain
correlation coefficients of about 98.3% for the comparison between the
simulated density fields and the galaxy density field in log-space with
Gaussian smoothing scales of r_S=3.5 Mpc/h (74% for r_S=1.4 Mpc/h). The cross
power-spectra show correlations with the galaxy distribution which weaken
towards smaller length scales until they vanish at scales of 2.2-3.0 Mpc/h. The
simulations we present provide a fully nonlinear density and velocity field
with a high level of correlation with the observed galaxy distribution at
scales of a few Mpc.


title:
Elliptic Flow from a Beam Energy Scan: a signature of a phase transition
  to the Quark-Gluon Plasma

abstract:
  We employ a relativistic transport theory to describe the fireball expansion
of the matter created in ultra-relativistic heavy-ion collisions (uRHICs).
Developing an approach to fix locally the shear viscosity to entropy density
$\eta/s$, we study the impact of a temperature dependent $\eta/s(T)$ on the
build-up of the elliptic flow, $v_2$, a measure of the angular anisotropy in
the particle production. Beam Energy Scan from $\sqrt{s_{NN}}= \rm 62.4 GeV$ at
RHIC up to 2.76 TeV at LHC has shown that the $v_2(p_T)$ as a function of the
transverse momentum $p_T$ appears to be nearly invariant with energy. We show
that such a surprising behavior is determined by a rise and fall of $\eta/s(T)$
with a minimum at $T\sim T_c$, as one would expect if the matter undergoes a
phase transition or a cross-over. This provides an evidence for phase
transition occurring in the uRHIC's and a first constraint on the temperature
dependence of $\eta/s$. In particular, a constant $\eta/s$ at all temperatures
or a too strong T-dependence would cause a breaking of the scaling of
$v_2(p_T)$ with the energy.


title: Flexural mode of graphene on a substrate

abstract:
  Out of plane vibrations are suppressed in graphene layers placed on a
substrate. These modes, in suspended samples, are relevant for the
understanding of properties such as the resistivity, the thermal expansion
coefficient, and other. We present a general framework for the study of the
properties of out of plane modes in graphene on different substrates. We use
the model to estimate the substrate induced changes in the thermal expansion
coefficient, or in the temperature dependence of the resistivity.


title:
The Yield-Strain and Shear-Band Direction in Amorphous Solids Under
  General Loading

abstract:
  It is well known experimentally that well-quenched amorphous solids exhibit a
plastic instability in the form of a catastrophic shear localization at a well
defined value of the external strain. The instability may develop to a
shear-band that in some cases is followed by a fracture. It is also known that
the values of the yield-strain (and yield-stress), as well as the direction of
the shear band with respect to the principal stress axis, vary considerably
with variations in the external loading conditions. In this paper we present a
microscopic theory of these phenomena for 2-dimensional athermal amorphous
solids that are strained quasi-statically. We present analytic formulae for the
yield-strains for different loading conditions, and well as for the angles of
the shear bands. We explain that the external loading conditions determine the
eigenvalues of the quadrupolar Eshelby inclusions which model the non-affine
displacement field. These inclusions model elementary plastic events and
determine both the yield-strain and the direction of the shear-band. We show
that the angles of the shear bands with respect to the principal stress axis
are limited theoretically between $30^o$ and $60^o$. Available experimental
data conform to this prediction.


title: Electromagnetic design of the KATRIN large-volume air coil system

abstract:
  The KATRIN experiment is designed to determine the absolute neutrino mass
scale with a sensitivity of 200 meV (90 % CL) by measuring the electron energy
spectrum close to the endpoint of molecular tritium beta decay. Electrons from
a high-intensity gaseous tritium source are guided by a strong magnetic field
of a few T to the analyzing plane of the main spectrometer where an integral
energy analysis takes place in a low field region (B<0.5 mT). An essential
design feature to obtain adiabatic electron transport through this spectrometer
is a large volume air coil system surrounding the vessel. The system has two
key tasks: to adjust and fine-tune the magnetic guiding field (Low Field
Correction System), as well as to compensate the distorting effects of the
earth magnetic field (Earth Field Compensation System). In this paper we
outline the key electromagnetic design issues for this very large air coil
system, which allows for well-defined electron transmission and optimized
background reduction in the KATRIN main spectrometer.


title:
Exact protein distributions for stochastic models of gene expression
  using partitioning of Poisson processes

abstract:
  Stochasticity in gene expression gives rise to fluctuations in protein levels
across a population of genetically identical cells. Such fluctuations can lead
to phenotypic variation in clonal populations, hence there is considerable
interest in quantifying noise in gene expression using stochastic models.
However, obtaining exact analytical results for protein distributions has been
an intractable task for all but the simplest models. Here, we invoke the
partitioning property of Poisson processes to develop a mapping that
significantly simplifies the analysis of stochastic models of gene expression.
The mapping leads to exact protein distributions using results for mRNA
distributions in models with promoter-based regulation. Using this approach, we
derive exact analytical results for steady-state and time-dependent
distributions for the basic 2-stage model of gene expression. Furthermore, we
show how the mapping leads to exact protein distributions for extensions of the
basic model that include the effects of post-transcriptional and
post-translational regulation. The approach developed in this work is widely
applicable and can contribute to a quantitative understanding of stochasticity
in gene expression and its regulation.


title: Two-point free energy distribution function in (1+1) directed polymers

abstract:
  In this brief technical communication it is demonstrated how using Bethe
ansatz technique the explicit expression for the two-point free energy
distribution function in (1+1) directed polymers can be derived in rather
simple way. Obtained result is equivalent to the one derived earlier by Prolhac
and Spohn.


title: Public key exchange using semidirect product of (semi)groups

abstract:
  In this paper, we describe a brand new key exchange protocol based on a
semidirect product of (semi)groups (more specifically, on extension of a
(semi)group by automorphisms), and then focus on practical instances of this
general idea. Our protocol can be based on any group, in particular on any
non-commutative group. One of its special cases is the standard Diffie-Hellman
protocol, which is based on a cyclic group. However, when our protocol is used
with a non-commutative (semi)group, it acquires several useful features that
make it compare favorably to the Diffie-Hellman protocol. Here we also suggest
a particular non-commutative semigroup (of matrices) as the platform and show
that security of the relevant protocol is based on a quite different assumption
compared to that of the standard Diffie-Hellman protocol.


title: Origins of barchan dune asymmetry: insights from numerical simulations

abstract:
  Barchan dunes --- crescent-shaped dunes that form in areas of unidirectional
winds and low sand availability --- commonly display an asymmetric shape, with
one limb extended downwind. Several factors have been identified as potential
causes for barchan dune asymmetry on Earth and Mars: asymmetric bimodal wind
regime, topography, influx asymmetry and dune collision. However, the dynamics
and potential range of barchan morphologies emerging under each specific
scenario that leads to dune asymmetry are far from being understood. In the
present work, we use dune modeling in order to investigate the formation and
evolution of asymmetric barchans. We find that a bimodal wind regime causes
limb extension when the divergence angle between primary and secondary winds is
larger than $90^{\circ}$, whereas the extended limb evolves into a seif dune if
the ratio between secondary and primary transport rates is larger than 25%.
Calculations of dune formation on an inclined surface under constant wind
direction also lead to barchan asymmetry, however no seif dune is obtained from
surface tilting alone. Asymmetric barchans migrating along a tilted surface
move laterally, with transverse migration velocity proportional to the slope of
the terrain. Limb elongation induced by topography can occur when a barchan
crosses a topographic rise. Furthermore, transient asymmetric barchan shapes
with extended limb also emerge during collisions between dunes or due to an
asymmetric influx. Our findings can be useful for making quantitative inference
on local wind regimes or spatial heterogeneities in transport conditions of
planetary dune fields hosting asymmetric barchans.


title: Unifying the Linear Time-Branching Time Spectrum of Process Semantics

abstract:
  Van Glabbeek's linear time-branching time spectrum is one of the most
relevant work on comparative study on process semantics, in which semantics are
partially ordered by their discrimination power. In this paper we bring forward
a refinement of this classification and show how the process semantics can be
dealt with in a uniform way: based on the very natural concept of constrained
simulation we show how we can classify the spectrum in layers; for the families
lying in the same layer we show how to obtain in a generic way equational,
observational, logical and operational characterizations; relations among
layers are also very natural and differences just stem from the constraint
imposed on the simulations that rule the layers. Our methodology also shows how
to achieve a uniform treatment of semantic preorders and equivalences.


title:
Third Party Privacy Preserving Protocol for Perturbation Based
  Classification of Vertically Fragmented Data Bases

abstract:
  Privacy is become major issue in distributed data mining. In the literature
we can found many proposals of privacy preserving which can be divided into two
major categories that is trusted third party and multiparty based privacy
protocols. In case of trusted third party models the conventional asymmetric
cryptographic based techniques will be used and in case of multi party based
protocols data perturbed to make sure no other party to understand original
data. In order to enhance security features by combining strengths of both
models in this paper, we propose to use data perturbed techniques in third
party privacy preserving protocol to conduct the classification on vertically
fragmented data bases. Specially, we present a method to build Naive Bayes
classification from the disguised and decentralized databases. In order to
perform classification we propose third party protocol for secure computations.
We conduct experiments to compare the accuracy of our Naive Bayes with the one
built from the original undisguised data. Our results show that although the
data are disguised and decentralized, our method can still achieve fairly high
accuracy.


title:
On invariance of order and the area property for finite-type entire
  functions

abstract:
  Let f be an entire function that has only finitely many critical and
asymptotic values. Up to topological equivalence, the function $f$ is
determined by combinatorial information, more precisely by an infinite graph
known as a "line-complex". In this note, we discuss the natural question
whether the order of growth of an entire function is determined by this
combinatorial information.
  The search for conditions that imply a positive answer to this question leads
us to the "area property", which turns out to be related to many interesting
and important questions in conformal dynamics and function theory. These
include a conjecture of Eremenko and Lyubich, the measurable dynamics of entire
functions, and pushforwards of quadratic differentials.
  We also discuss evidence that invariance of order and the area property fail
in general.


title: On a certain class of $\K$ Banach spaces

abstract:
  Using a strengthening of the concept of $\K$ set, introduced in this paper,
we study a certain subclass of the class of $\K$ Banach spaces; the so called
strongly $\K$ Banach spaces. This class of spaces includes subspaces of
strongly weakly compactly generated (SWCG) as well as Polish Banach spaces and
it is related to strongly weakly $\mathcal{K}$--analytic (SWKA) Banach spaces
as the known classes of $\K$ and weakly $\mathcal{K}$--analytic (WKA) Banach
spaces are related.


title:
Competition between the Superconducting Proximity Effect and Coulomb
  Interactions in a Graphene Andreev Interferometer

abstract:
  We have investigated transport through graphene Andreev interferometers
exhibiting reentrance of the superconducting proximity effect. We observed a
crossover in the Andreev conductance oscillations as a function of gate voltage
($V_{BG}$). At high $V_{BG}$ the energy-dependent oscillation amplitude
exhibits a scaling predicted for non-interacting electrons, which breaks down
at low $V_{BG}$. The phenomenon is a manifestation of electron-electron
interactions, whose main effect is to shorten the single-particle phase
coherence time $\tau_\phi$. These results indicate that graphene provides a
useful experimental platform to investigate the competition between
superconducting proximity effect and interactions.


title:
The infimum of the volumes of convex polytopes of any given facet areas
  is 0

abstract:
  We prove the theorem mentioned in the title, for ${\mathbb{R}}^n$, where $n
\ge 3$. The case of the simplex was known previously. Also, the case $n=2$ was
settled, but there the infimum was some well-defined function of the side
lengths. We also consider the cases of spherical and hyperbolic $n$-spaces.
There we give some necessary conditions for the existence of a convex polytope
with given facet areas, and some partial results about sufficient conditions
for the existence of (convex) tetrahedra.


title:
The skyrmion lattice phase in three dimensional chiral magnets from
  Monte Carlo simulations

abstract:
  Chiral magnets, such as MnSi, display a rich finite temperature phase diagram
in an applied magnetic field. The most unusual of the phases encountered is the
so called A-phase characterized by a triangular lattice of skyrmion tubes. Its
existence cannot be captured within a mean-field treatment of a Landau-Ginzburg
functional but thermal fluctuations to Gaussian order are required to stabilize
it. In this note we go beyond Gaussian order in a fully non-perturbative study
of a three dimensional lattice spin model using classical Monte Carlo
simulations. We demonstrate that the A-phase is indeed stabilized by thermal
fluctuations and furthermore we reproduce the full phase diagram found in
experiment. The thermodynamic signatures of the helimagnetic transition upon
cooling from the paramagnet are qualitatively consistent with experimental
findings and lend further support to the Brazovskii scenario which describes a
fluctuation driven first order transition due to the abundance of soft modes.


title:
Where Does Black Hole Entropy Lie? Some Remarks on Area-Entropy Law,
  Holographic Principle and Noncommutative Space-Time

abstract:
  In confrontation with serious and fundamental problems towards ultimate
theory of quantum gravity and physics of Planck scale, we emphasize the
importance of underlying noncommutative space-time such as Snyder's or Yang's
Lorentz-covariant quantized space-time. The background of Bekenstein-Hawking's
Area-entropy law and Holographic principle is now substantially understood in
terms of {\it Kinematical} Holographic Relation [KHR], which holds in Yang's
quantized space-time as the result of the kinematical reduction of spatial
degrees of freedom caused by its own nature of noncommutative geometry. [KHR]
implies a definite proportional relation, $ n^L_{\rm dof} (V_d^L)= {\cal A}
(V_d^L) / G_d$, between the number of spatial degrees of freedom $n^L_{\rm dof}
(V_d^L)$ inside of any $d-$dimensional spherical volume $V_d^L$ with radius $L
$ and its boundary area ${\cal A} (V_d^L).$ It yields a substantial basis for
our new area-entropy law of black holes and further enables us to connect "The
First Law of Black Hole Mechanics" with "The Thermodynamics of Black Holes,"
towards our final goal: {\it Statistical} and {\it substantial} understanding
of area-entropy law of black holes under a novel concept of noncommutative
quantized space-time.


title: Duality covariant multi-centre black hole systems

abstract:
  We present a manifestly duality covariant formulation of the composite
non-BPS and almost-BPS systems of multi-centre black hole solutions in four
dimensions. The method of nilpotent orbits is used to define the two systems in
terms of first order flow equations that transform covariantly under the
duality group. Subsequently, we rewrite both systems of equations in terms of
real, manifestly duality covariant, linear systems of Poisson equations.
Somewhat unexpectedly, we find that the two systems are naturally described by
the same equations involving space dependent abelian isometries that are
conjugate to T-dualities by similarity transformations.


title: Vertical organic spin valves in perpendicular magnetic fields

abstract:
  We report the results of magnetoresistance measurements in vertical organic
spin valves with the magnetic field oriented perpendicular to the layer stack.
The magnetoresistance measurements were performed after carefully preparing
either parallel or antiparallel in-plane magnetization states of the magnetic
electrodes in order to observe traces of Hanle precession. Due to the low
mobility in organic semiconductors the transit time of spin polarized carriers
should allow for precession of the spins in perpendicular fields which in
statistical average would quench the magnetoresistance. However, in none of the
experiments we do observe any change in resistance while sweeping the
perpendicular field, up to the point where the electrode's magnetization starts
to reorient. This absence of Hanle type effects indicates that the
magnetoresistance is not based on the injection of spin polarized electrons
into the organic semiconductor but rather on tunneling through pinholes
superimposed with tunneling anisotropic magnetoresistance.


title:
When Privacy meets Security: Leveraging personal information for
  password cracking

abstract:
  Passwords are widely used for user authentication and, despite their
weaknesses, will likely remain in use in the foreseeable future.
Human-generated passwords typically have a rich structure, which makes them
susceptible to guessing attacks. In this paper, we study the effectiveness of
guessing attacks based on Markov models. Our contributions are two-fold. First,
we propose a novel password cracker based on Markov models, which builds upon
and extends ideas used by Narayanan and Shmatikov (CCS 2005). In extensive
experiments we show that it can crack up to 69% of passwords at 10 billion
guesses, more than all probabilistic password crackers we compared again t.
Second, we systematically analyze the idea that additional personal information
about a user helps in speeding up password guessing. We find that, on average
and by carefully choosing parameters, we can guess up to 5% more passwords,
especially when the number of attempts is low. Furthermore, we show that the
gain can go up to 30% for passwords that are actually based on personal
attributes. These passwords are clearly weaker and should be avoided. Our
cracker could be used by an organization to detect and reject them. To the best
of our knowledge, we are the first to systematically study the relationship
between chosen passwords and users' personal information. We test and validate
our results over a wide collection of leaked password databases.


title:
Landau-Zener tunneling of a single Tb3+ magnetic moment allowing the
  electronic read-out of a nuclear spin

abstract:
  A multi-terminal device based on a carbon nanotube quantum dot was used at
very low tem- perature to probe a single electronic and nuclear spin embedded
in a bis-phthalocyanine Terbium (III) complex (TbPc2). A spin-valve signature
with large conductance jumps was found when two molecules were strongly coupled
to the nanotube. The application of a transverse field separated the magnetic
signal of both molecules and enabled single-shot read-out of the Terbium
nuclear spin. The Landau-Zener (LZ) quantum tunneling probability was studied
as a function of field sweep rate, establishing a good agreement with the LZ
equation and yielding the tunnel splitting \Delta. It was found that ?
increased linearly as a function of the transverse field. These studies are an
essential prerequisite for the coherent manipulation of a single nuclear spin
in TbPc2.


title: A Note on the Fourier coefficients of half-integral weight modular forms

abstract:
  In this note, we show that the algebraicity of the Fourier coefficients of
half-integral weight modular forms can be determined by checking the
algebraicity of the first few of them. We also give a necessary and sufficient
condition for a half-integral weight modular form to be in Kohnen's +-subspace
by considering only finitely many terms.


title:
The distinctions between $\Lambda$CDM and $f(T)$ gravity according
  Noether symmetry

abstract:
  Noether's theory offers us a useful tool to research the conserved quantities
and symmetries of the modified gravity theories, among which the $f(T)$ theory,
a generally modified teleparallel gravity, has been proposed to account for the
dark energy phenomena. By the Noether symmetry approach, we investigate the
power-law, exponential and polynomial forms of $f(T)$ theories. All forms of
$f(T)$ concerned in this work possess the time translational symmetry, which is
related with energy condition or Hamilton constraint. In addition, we find out
that the performances of the power-law and exponential forms are not pleasing.
It is rational adding a linear term $T$ to $T^n$ as the most efficient
amendment to resemble the teleparallel gravity or General Relativity on small
scales, ie., the scale of the solar system. The corresponding Noether symmetry
indicates that only time translational symmetry remains. Through numerically
calculations and observational data-sets constraining, the optimal form $\alpha
T + \beta T^{-1}$ is obtained, whose cosmological solution resembles the
standard $\Lambda$CDM best with lightly reduced cosmic age which can be
alleviated by introducing another $T^m$ term. More important is that we find
the significant differences between $\Lambda$CDM and $f(T)$ gravity. The
$\Lambda$CDM model has also two additional symmetries and corresponding
positive conserved quantities, except the two negative conserved quantities.


title: Graph Reconstruction via Distance Oracles

abstract:
  We study the problem of reconstructing a hidden graph given access to a
distance oracle. We design randomized algorithms for the following problems:
reconstruction of a degree bounded graph with query complexity
$\tilde{O}(n^{3/2})$; reconstruction of a degree bounded outerplanar graph with
query complexity $\tilde{O}(n)$; and near-optimal approximate reconstruction of
a general graph.


title: Partitions of Frobenius Rings Induced by the Homogeneous Weight

abstract:
  The values of the homogeneous weight are determined for finite Frobenius
rings that are a direct product of local Frobenius rings. This is used to
investigate the partition induced by this weight and its dual partition under
character-theoretic dualization. A characterization is given of those rings for
which the induced partition is reflexive or even self-dual.


title: Ballistic interferences in suspended graphene

abstract:
  Graphene is a 2-dimensional (2D) carbon allotrope with the atoms arranged in
a honeycomb lattice. The low-energy electronic excitations in this 2D crystal
are described by massless Dirac fermions that have a linear dispersion relation
similar to photons. Taking advantage of this optics-like electron dynamics,
generic optical elements like lenses, beam splitters and wave guides have been
proposed for electrons in engineered ballistic graphene. Tuning of these
elements relies on the ability to adjust the carrier concentration in defined
areas, including the possibility to create bipolar regions of opposite charge
(p-n regions). However, the combination of ballistic transport and complex
electrostatic gating remains challenging. Here, we report on the fabrication
and characterization of fully suspended graphene p-n junctions. By local
electro-static gating, resonant cavities can be defined, leading to complex
Fabry-Perot interference patterns in the unipolar and the bipolar regime. The
amplitude of the observed conductance oscillations accounts for quantum
interference of electrons that propagate ballistically over long distances
exceeding 1 micron. We also demonstrate that the visibility of the interference
pattern is enhanced by Klein collimation at the p-n interface. This finding
paves the way to more complex gate-controlled ballistic graphene devices and
brings electron optics in graphene closer to reality.


title: Lp-Regularized Least Squares (0<p<1) and Critical Path

abstract:
  The least squares problem is formulated in terms of Lp quasi-norm
regularization (0<p<1). Two formulations are considered: (i) an Lp-constrained
optimization and (ii) an Lp-penalized (unconstrained) optimization. Due to the
nonconvexity of the Lp quasi-norm, the solution paths of the regularized least
squares problem are not ensured to be continuous. A critical path, which is a
maximal continuous curve consisting of critical points, is therefore considered
separately. The critical paths are piecewise smooth, as can be seen from the
viewpoint of the variational method, and generally contain non-optimal points
such as saddle points and local maxima as well as global/local minima. Along
each critical path, the correspondence between the regularization parameters
(which govern the 'strength' of regularization in the two formulations) is
non-monotonic and, more specifically, it has multiplicity. Two paths of
critical points connecting the origin and an ordinary least squares (OLS)
solution are highlighted. One is a main path starting at an OLS solution, and
the other is a greedy path starting at the origin. Part of the greedy path can
be constructed with a generalized Minkowskian gradient. The breakpoints of the
greedy path coincide with the step-by-step solutions generated by using
orthogonal matching pursuit (OMP), thereby establishing a direct link between
OMP and Lp-regularized least squares.


title: Destroying the event horizon of regular black holes

abstract:
  Recently, several authors have studied the possibility of overspinning or
overcharging an existing black hole to destroy its event horizon and make the
central singularity naked. When all the effects are properly taken into
account, any attempt to destroy the black hole seems to be doomed to fail, in
agreement with the weak cosmic censorship conjecture. In this letter, we study
the possibility of destroying the event horizon of regular black holes. These
objects have no central singularity and therefore they are not protected by the
cosmic censorship hypothesis. Our results strongly support the conclusion that
regular black holes can be destroyed. If we believe that the central
singularity in astrophysical black holes is solved by quantum gravity effects,
we might have a chance to see the black hole's internal region and observe
quantum gravity phenomena. As our finding implies the violation of the black
hole's area theorem, the collision of two black holes may release an amount of
energy exceeding the Hawking bound, which can be experimentally tested by
gravitational wave detectors.


title:
Fixed-parameter algorithms for minimum cost edge-connectivity
  augmentation

abstract:
  We consider connectivity-augmentation problems in a setting where each
potential new edge has a nonnegative cost associated with it, and the task is
to achieve a certain connectivity target with at most p new edges of minimum
total cost. The main result is that the minimum cost augmentation of
edge-connectivity from k-1 to k with at most p new edges is fixed-parameter
tractable parameterized by p and admits a polynomial kernel. We also prove the
fixed-parameter tractability of increasing edge-connectivity from 0 to 2, and
increasing node-connectivity from 1 to 2.


title:
Dissecting Deuteron Compton Scattering I: The Observables with Polarised
  Initial States

abstract:
  A complete set of linearly independent observables in Compton scattering with
arbitrarily polarised real photons off an arbitrarily polarised spin-1 target
is introduced, for the case that the final-state polarisations are not
measured. Adopted from the one widely used e.g. in deuteron photo-dissociation,
it consists of 18 terms: the unpolarised cross section, the beam asymmetry, 4
target asymmetries and 12 asymmetries in which both beam and target are
polarised. They are expressed by the helicity amplitudes and -- where available
-- related to observables discussed by other authors. As application to
deuteron Compton scattering, their dependence on the (isoscalar) scalar and
spin dipole polarisabilities of the nucleon is explored in Chiral Effective
Field Theory with dynamical Delta(1232) degrees of freedom at order
$e^2\delta^3$. Some asymmetries are sensitive to only one or two dipole
polarisabilities, making them particularly attractive for experimental studies.
At a photon energy of 100 MeV, a set of 5 observables is identified from which
one may be able to extract the spin polarisabilities of the nucleon. These are
experimentally realistic but challenging and mostly involve tensor-polarised
deuterons. Relative to Compton scattering from a nucleon, sensitivity to the
"mixed" spin polarisabilities $\gamma_{E1M2}$ and $\gamma_{M1E2}$ is increased
because of interference with the D wave component of the deuteron and with its
pion-exchange current. An interactive Mathematica 9.0 notebook with results for
all observables at photon energies up to 120 MeV is available from
hgrie@gwu.edu.
  Note May 2017/April 2018: This arXiv version presents the article including
the corrections in the Errata Eur. Phys. J. A53 (2017) 113 and A54 (2018) 57 to
ibid. A49 (2013) 100. This affects Eqs. (2.12) to (2.14), Figs. 4, 7 to 10, 12,
14 to 16, 18 to 20, 22 and 23, and the corresponding, related text.


title:
Reaction-diffusion systems with constant diffusivities: conditional
  symmetries and form-preserving transformations

abstract:
  Q-conditional symmetries (nonclassical symmetries) for a general class of
two-component reaction-diffusion systems with constant diffusivities are
studied. Using the recently introduced notion of Q-conditional symmetries of
the first type (R. Cherniha J. Phys. A: Math. Theor., 2010. vol. 43., 405207),
an exhaustive list of reaction-diffusion systems admitting such symmetry is
derived. The form-preserving transformations for this class of systems are
constructed and it is shown that this list contains only non-equivalent
systems. The obtained symmetries permit to reduce the reaction-diffusion
systems under study to two-dimensional systems of ordinary differential
equations and to find exact solutions. As a non-trivial example, multiparameter
families of exact solutions are explicitly constructed for two nonlinear
reaction-diffusion systems. A possible interpretation to a biologically
motivated model is presented.


title: Graphene Based Optical Phase Modulation

abstract:
  In this paper we report phase modulation obtained by inducing a capacitive
charge on graphene layers embedded in the core of a waveguide. There is a
biasing regime in which graphene absorption is negligible but large index
variations can be achieved with a voltage-length product as small as
$V_\pi\,L_\pi \simeq 0.04 $\,V\,cm . Examples of phase induced changes are
computed for straight waveguides and for microring resonators showing the
possibility to implement several optoelectronic functionalities as modulators,
tunable filters, and switches.


title: Scalar Trapping and Saxion Cosmology

abstract:
  We study in detail the dynamics of a scalar field in thermal bath with
symmetry breaking potential. In particular, we focus on the process of trapping
of a scalar field at an enhanced symmetry point through the thermal/non-thermal
particle production, taking into account the interactions of produced particles
with the standard model particles. As an explicit example, we revisit the
saxion dynamics with an initial amplitude much larger than the Peccei-Quinn
scale and show that the saxion trapping phenomenon happens for the most cases
and it often leads to thermal inflation. We also study the saxion dynamics
after thermal inflation, and it is shown that thermal dissipation effect on the
saxion can relax the axion overproduction problem from the saxion decay.


title:
Nonlinear Dynamics of Ion Concentration Polarization in Porous Media:
  The Leaky Membrane Model

abstract:
  The conductivity of highly charged membranes is nearly constant, due to
counter-ions screening pore surfaces. Weakly charged porous media, or "leaky
membranes", also contain a significant concentration of co-ions, whose
depletion at high current leads to ion concentration polarization and
conductivity shock waves. To describe these nonlinear phenomena the absence of
electro-osmotic flow, a simple Leaky Membrane Model is formulated, based on
macroscopic electroneutrality and Nernst-Planck ionic fluxes. The model is
solved in cases of unsupported binary electrolytes: steady conduction from a
reservoir to a cation-selective surface, transient response to a current step,
steady conduction to a flow-through porous electrode, and steady conduction
between cation-selective surfaces in cross flow. The last problem is motivated
by separations in leaky membranes, such as shock electrodialysis. The article
begins with a tribute to Neal Amundson, whose pioneering work on shock waves in
chromatography involved similar mathematics.


title:
Robust error correction for real-valued signals via message-passing
  decoding and spatial coupling

abstract:
  We revisit the error correction scheme of real-valued signals when the
codeword is corrupted by gross errors on a fraction of entries and a small
noise on all the entries. Combining the recent developments of approximate
message passing and the spatially-coupled measurement matrix in compressed
sensing we show that the error correction and its robustness towards noise can
be enhanced considerably. We discuss the performance in the large signal limit
using previous results on state evolution, as well as for finite size signals
through numerical simulations. Even for relatively small sizes, the approach
proposed here outperforms convex-relaxation-based decoders.


title:
Effect of Dresselhaus spin-orbit coupling on spin dephasing in
  asymmetric and macroscopically symmetric (110)-grown quantum wells

abstract:
  We develop the microscopic theory of electron spin dephasing in (110)-grown
quantum wells where the electron scattering time is comparable to or exceeds
the period of spin precession in the effective magnetic field caused by
spin-orbit coupling. Structures with homogeneous and fluctuating Rashba field,
which triggers the dephasing of electron spins aligned along the growth
direction, are analyzed. We show that the Dresselhaus field, which is always
present in zinc-blende-type quantum wells, suppresses the spin dephasing
enabling very long spin lifetime of conduction electrons. The dependence of the
spin lifetime on the electron mobility is found to be nonmonotonic reaching the
minimum in structures where the scattering time is comparable to the period of
spin precession in the effective magnetic field.


title: Time evolution of Wikipedia network ranking

abstract:
  We study the time evolution of ranking and spectral properties of the Google
matrix of English Wikipedia hyperlink network during years 2003 - 2011. The
statistical properties of ranking of Wikipedia articles via PageRank and
CheiRank probabilities, as well as the matrix spectrum, are shown to be
stabilized for 2007 - 2011. A special emphasis is done on ranking of Wikipedia
personalities and universities. We show that PageRank selection is dominated by
politicians while 2DRank, which combines PageRank and CheiRank, gives more
accent on personalities of arts. The Wikipedia PageRank of universities
recovers 80 percents of top universities of Shanghai ranking during the
considered time period.


title:
The Onset of Differentiation and Internal Evolution: the case of 21
  Lutetia

abstract:
  Asteroid 21 Lutetia, visited by the Rosetta spacecraft, plays a crucial role
in the reconstruction of primordial phases of planetary objects. Its high bulk
density and its primitive chondritic crust (Weiss et al. 2011) suggest that
Lutetia could be partially differentiated. We developed a numerical code, also
used for studying the geophysical history of Vesta (Formisano et al.,
submitted), to explore several scenarios of internal evolution of Lutetia,
differing in the strength of radiogenic sources and in the global
post-sintering porosity. The only significant heat source for partial
differentiation is represented by Al26, the other possible sources (Fe60,
accretion and differentiation) being negligible. In scenarios in which Lutetia
completed its accretion in less than 0.7 Ma from injection of Al26 in Solar
Nebula and for post-sintering values of macroporosity not exceeding 30 vol. %,
the asteroid experienced only partial differentiation. The formation of the
proto-core, a structure enriched in metals and also containing pristine
silicates, requires from 1 to 4 Ma: the size of the proto-core varies from 6 to
30 km.


title: Optimal Kullback-Leibler Aggregation via Information Bottleneck

abstract:
  In this paper, we present a method for reducing a regular, discrete-time
Markov chain (DTMC) to another DTMC with a given, typically much smaller number
of states. The cost of reduction is defined as the Kullback-Leibler divergence
rate between a projection of the original process through a partition function
and a DTMC on the correspondingly partitioned state space. Finding the reduced
model with minimal cost is computationally expensive, as it requires an
exhaustive search among all state space partitions, and an exact evaluation of
the reduction cost for each candidate partition. Our approach deals with the
latter problem by minimizing an upper bound on the reduction cost instead of
minimizing the exact cost; The proposed upper bound is easy to compute and it
is tight if the original chain is lumpable with respect to the partition. Then,
we express the problem in the form of information bottleneck optimization, and
propose using the agglomerative information bottleneck algorithm for searching
a sub-optimal partition greedily, rather than exhaustively. The theory is
illustrated with examples and one application scenario in the context of
modeling bio-molecular interactions.


title: Status of detector development for the European XFEL

abstract:
  The European X-ray Free Electron Laser (XFEL.EU) will provide
as-yet-unrivaled peak brilliance and ultra-short pulses of spatially coherent
X-rays with a pulse length of less than 100 fs in the energy range between 0.25
and 25 keV. The high radiation intensity and ultra-short pulse duration will
open a window for novel scientific techniques and will allow to explore new
phenomena in biology, chemistry, material science, as well as matter at high
energy density, atomic, ion and molecular physics. The variety of scientific
applications and especially the unique XFEL.EU time structure require adequate
instrumentation to be developed in order to exploit the full potential of the
light source. To make optimal use of the unprecedented capabilities of the
European XFEL and master these vast technological challenges, the European XFEL
GmbH has started a detector R&D program. The technology concepts of the
detector system presently under development are complementary in their
performance and will cover the requirements of a large fraction of the
scientific applications envisaged for the XFEL.EU facility. The actual status
of the detector development projects which includes ultra-fast 2D imaging
detectors, low repetition rate 2D detectors as well as strip detectors for e.g.
spectroscopy applications and the infrastructure for the detectors' calibration
and tests will be presented. Furthermore, an overview of the forthcoming
implementation phase of the European XFEL in terms of detector R&D will be
given.


title:
Growth estimates for pseudo-dissipative holomorphic maps in Banach
  spaces

abstract:
  In this paper we introduce a class of pseudo-dissipative holomorphic maps
which contains, in particular, the class of infinitesimal generators of
semigroups of holomorphic maps on the unit ball of a complex Banach space. We
give a growth estimate for maps of this class. In particular, it follows that
pseudo-dissipative maps on the unit ball of (infinite-dimensional) Banach
spaces are bounded on each domain strictly contained inside the ball. We also
present some applications.


title: Asymptotic Translation Length in the Curve Complex

abstract:
  We show that when the genus and punctures of a surface are directly
proportional by some rational number the minimal asymptotic translation length
in the curve complex has behavior inverse to the square of the Euler
characteristic. We also show that when the genus is fixed and the number of
punctures varies the behavior is inverse to the Euler characteristic.


title: On the binomial arithmetical rank of lattice ideals

abstract:
  To any lattice $L \subset \mathbb{Z}^{m}$ one can associate the lattice ideal
$I_{L} \subset K[x_{1},...,x_{m}]$. This paper concerns the study of the
relation between the binomial arithmetical rank and the minimal number of
generators of $I_{L}$. We provide lower bounds for the binomial arithmetical
rank and the $\mathcal{A}$-homogeneous arithmetical rank of $I_{L}$.
Furthermore, in certain cases we show that the binomial arithmetical rank
equals the minimal number of generators of $I_{L}$. Finally we consider a class
of determinantal lattice ideals and study some algebraic properties of them.


title: The Structure of Z-related sets

abstract:
  The paper presents some new results on Z-related sets obtained by
computational methods. We give a complete enumeration of all Z-related sets in
$\mathbb{Z}_{N}$ for small $N$. Furthermore, we establish that there is a
reasonable permutation group action representing the Z-relation.


title: Enumeration of Vuza Canons

abstract:
  A Vuza canon is a non periodic factorization of the finite cyclic $
\mathbb{Z}_{N}$. The aim of this paper is to present some new results for
generating Vuza canons, and to give new minoration of their number for some
values of N.


title: Smooth Sums over Smooth $k$-Free Numbers and Statistical Mechanics

abstract:
  We provide an asymptotic estimate for certain sums over k-free integers with
small prime factors. These sums depend upon a complex parameter \alpha and
involve a smooth cut-off f. They are a variation of several classical
number-theoretical sums. One term in the asymptotics is an integral operator
whose kernel is the \alpha-convolution of the Dickman-de Bruijn distribution,
and the other term is explicitly estimated. The trade-off between the value of
\alpha and the regularity of f is discussed. This work generalizes the results
of tow previous papers by the author and Ya.G. Sinai, where k=2 and \alpha=1.


title:
The domain and property illusion of anomalous anisotropic electric
  conductivity

abstract:
  The unique determination of electrical conductivity is extensively studied
for isotropic conductivity ever since Calderon's suggestion of the EIT
(Electrical Impedance Tomography) problem. However, it is known that there are
many anisotropic conductivities producing the same Dirichlet-to-Neumann map;
moreover the anisotropic conductivities giving the same Dirichlet-to-Neumann
map are classified using the equivalence relation with respect to the change of
variables. The change of variable argument is applied to the theory of
near-cloaking: We are under an illusion that the domain of anomaly is of a much
smaller size than actually it is. For this paper, we considered not only the
illusion of the domain of the anomaly, but also the illusion of the property of
the anomaly when the background anisotropic conductivity is known.


title: Single-photon quadratic optomechanics

abstract:
  We present exact analytical solutions to study the coherent interaction
between a single photon and the mechanical motion of a membrane in quadratic
optomechanics. We consider single-photon emission and scattering when the
photon is initially inside the cavity and in the fields outside the cavity,
respectively. Using our solutions, we calculate the single-photon emission and
scattering spectra, and find relations between the spectral features and the
system's inherent parameters, such as: the optomechanical coupling strength,
the mechanical frequency, and the cavity-field decay rate. In particular, we
clarify the conditions for the phonon sidebands to be visible. We also study
the photon-phonon entanglement for the long-time emission and scattering
states. The linear entropy is employed to characterize this entanglement by
treating it as a bipartite one between a single mode of phonons and a single
photon.


title: Ovarian volume throughout life: a validated normative model

abstract:
  The measurement of ovarian volume has been shown to be a useful indirect
indicator of the ovarian reserve in women of reproductive age, in the diagnosis
and management of a number of disorders of puberty and adult reproductive
function, and is under investigation as a screening tool for ovarian cancer. To
date there is no normative model of ovarian volume throughout life. By
searching the published literature for ovarian volume in healthy females, and
using our own data from multiple sources (combined n = 59,994) we have
generated and robustly validated the first model of ovarian volume from
conception to 82 years of age. This model shows that 69% of the variation in
ovarian volume is due to age alone. We have shown that in the average case
ovarian volume rises from 0.7 mL (95% CI 0.4 -- 1.1 mL) at 2 years of age to a
peak of 7.7 mL (95% CI 6.5 -- 9.2 mL) at 20 years of age with a subsequent
decline to about 2.8mL (95% CI 2.7 -- 2.9 mL) at the menopause and smaller
volumes thereafter. Our model allows us to generate normal values and ranges
for ovarian volume throughout life. This is the first validated normative model
of ovarian volume from conception to old age; it will be of use in the
diagnosis and management of a number of diverse gynaecological and reproductive
conditions in females from birth to menopause and beyond.


title:
Performance Analysis of Protograph LDPC Codes for Nakagami-$m$ Fading
  Relay Channels

abstract:
  In this paper, we investigate the error performance of the protograph (LDPC)
codes over Nakagami-$m$ fading relay channels. We first calculate the decoding
thresholds of the protograph codes over such channels with different fading
depths (i.e., different values of $m$) by exploiting the modified protograph
extrinsic information transfer (PEXIT) algorithm. Furthermore, based on the
PEXIT analysis and using Gaussian approximation, we derive the bit-error-rate
(BER) expressions for the error-free (EF) relaying protocol and
decode-and-forward (DF) relaying protocol. We finally compare the threshold
with the theoretical BER and the simulated BER results of the protograph codes.
It reveals that the performance of DF protocol is approximately the same as
that of EF protocol. Moreover, the theoretical BER expressions, which are shown
to be reasonably consistent with the decoding thresholds and the simulated
BERs, are able to evaluate the system performance and predict the decoding
threshold with lower complexity as compared to the modified PEXIT algorithm. As
a result, this work can facilitate the design of the protograph codes for the
wireless communication systems.


title: Data-rich astronomy: mining synoptic sky surveys

abstract:
  In the last decade a new generation of telescopes and sensors has allowed the
production of a very large amount of data and astronomy has become, a data-rich
science; this transition is often labeled as: "data revolution" and "data
tsunami". The first locution puts emphasis on the expectations of the
astronomers while the second stresses, instead, the dramatic problem arising
from this large amount of data: which is no longer computable with traditional
approaches to data storage, data reduction and data analysis. In a new, age new
instruments are necessary, as it happened in the Bronze age when mankind left
the old instruments made out of stone to adopt the new, better ones made with
bronze. Everything changed, even the social structure. In a similar way, this
new age of Astronomy calls for a new generation of tools and, for a new
methodological approach to many problems, and for the acquisition of new
skills. The attems to find a solution to this problems falls under the umbrella
of a new discipline which originated by the intersection of astronomy,
statistics and computer science: Astroinformatics, (Borne, 2009; Djorgovski et
al., 2006).


title: Weighted statistical parameters for irregularly sampled time series

abstract:
  Unevenly spaced time series are common in astronomy because of the day-night
cycle, weather conditions, dependence on the source position in the sky,
allocated telescope time, corrupt measurements, for example, or be inherent to
the scanning law of satellites like Hipparcos and the forthcoming Gaia.
Irregular sampling often causes clumps of measurements and gaps with no data
which can severely disrupt the values of estimators. This paper aims at
improving the accuracy of common statistical parameters when linear
interpolation (in time or phase) can be considered an acceptable approximation
of a deterministic signal. A pragmatic solution is formulated in terms of a
simple weighting scheme, adapting to the sampling density and noise level,
applicable to large data volumes at minimal computational cost. Tests on time
series from the Hipparcos periodic catalogue led to significant improvements in
the overall accuracy and precision of the estimators with respect to the
unweighted counterparts and those weighted by inverse-squared uncertainties.
Automated classification procedures employing statistical parameters weighted
by the suggested scheme confirmed the benefits of the improved input
attributes. The classification of eclipsing binaries, Mira, RR Lyrae, Delta
Cephei and Alpha2 Canum Venaticorum stars employing exclusively weighted
descriptive statistics achieved an overall accuracy of 92 per cent, about 6 per
cent higher than with unweighted estimators.


title: EM-based Semi-blind Channel Estimation in AF Two-Way Relay Networks

abstract:
  We propose an expectation maximization (EM)-based algorithm for semi-blind
channel estimation of reciprocal channels in amplify-and-forward (AF) two-way
relay networks (TWRNs). By incorporating both data samples and pilots into the
estimation, the proposed algorithm provides substantially higher accuracy than
the conventional training-based approach. Furthermore, the proposed algorithm
has a linear computational complexity per iteration and converges after a small
number of iterations.


title: Derivation of Born Rule from Algebraic and Statistical Axioms

abstract:
  In the present paper we propose a new axiomatic system of algebraic and
statistical axioms as working hypotheses, from which Born rule can be seen to
emerge. In this process the concept of sectors defined as quasi-equivalence
classes of factor states plays a crucial role.

categories: quant-ph math-ph math.MP math.PR math.ST stat.TH


title:
Maskless and targeted creation of arrays of colour centres in diamond
  using focused ion beam technology

abstract:
  The creation of nitrogen-vacancy centres in diamond is nowadays well
controlled using nitrogen implantation and annealing. Although the
high-resolution placement of NV centres has been demonstrated using either
collimation through pierced AFM tips or masks with apertures made by electron
beam lithography, a targeted implantation into pre-defined structures in
diamond may not be achieved using these techniques. We show that a beam of
nitrogen ions can be focused to approximately 100 nm using focused ion beam
(FIB) technology. The nitrogen ion beam is produced using an electron cyclotron
resonance (ECR) plasma source. Combined with a scanning electron microscope,
the nitrogen-FIB offers new possibilities for the targeted creation of single
defects in diamond. This maskless technology is suitable for example for the
creation of optical centres in the cavities of photonic crystals or in diamond
tips for scanning magnetometry. Finally, we further show that by changing the
gas source from nitrogen to xenon, standard FIB milling capabilities are also
available within the same tool.


title: Closed exact Lagrangians in the symplectization of contact manifolds

abstract:
  For a certain class of exotic contact manifolds of dimension greater than 3,
we show that there is an abundance of closed exact Lagrangians in their
symplectization. All of these Lagrangians are displaceable by Hamiltonian
isotopy, and many of the examples are nulhomotopic.


title: An example of Newton's method for an equation in Gevrey series

abstract:
  In the context of complex WKB analysis, we discuss a one-dimensional
Schr\"odinger equation $ -h^2\partial_x^2 f(x,h) + [Q(x)+hQ_1(x,h)]f(x,h) =0, \
\ \ h\to 0, $ where $Q(x)$, $Q_1(x,h)$ are analytic near the origin $x=0$,
$Q(0)=0$, and $Q_1(x,h)$ is a factorially divergent power series in $h$. We
show that there is a change of independent variable $y=y(x,h)$, analytic near
$x=0$ and factorially divergent with respect to $h$, that transforms the above
Schr\"odinger equation to a canonical form. The proof goes by reduction to a
mildly nonlinear equation on $y(x,h)$ and by solving it using an appropriately
modified Newton's method of tangents. Our result generalizes that of Aoki,
Kawai, and Takei.


title: Is acetylene essential for carbon dust formation?

abstract:
  We have carried out an investigation of the chemical evolution of gas in
different carbon-rich circumstellar environments. Previous studies have tended
to invoke terrestrial flame chemistries, based on acetylene (C2H2) combustion
to model the formation of carbon dust, via Polycyclic Aromatic Hydrocarbons
(PAHs). In this work we pay careful attention to the accurate calculation of
the molecular photoreaction rate coefficients to ascertain whether there is a
universal formation mechanism for carbon dust in strongly irradiated
astrophysical environments. A large number of possible chemical channels may
exist for the formation of PAHs, so we have concentrated on the viability of
the formation of the smallest building block species, C2H2, in a variety of
carbon-rich stellar outflows. C2H2 is very sensitive to dissociation by UV
radiation. This sensitivity is tested, using models of the time-dependent
chemistry. We find that C2H2 formation is sensitive to some of the physical
parameters and that in some known sources of dust-formation it can never attain
appreciable abundances. Therefore multiple (and currently ill-defined)
dust-formation channels must exist.


title:
Exploring the tug of war between positive and negative interactions
  among savanna trees: Competition, dispersal, and protection from fire

abstract:
  Savannas are characterized by a discontinuous tree layer superimposed on a
continuous layer of grass. Identifying the mechanisms that facilitate this
tree-grass coexistence has remained a persistent challenge in ecology and is
known as the "savanna problem". In this work, we propose a model that combines
a previous savanna model (Calabrese et al., 2010), which includes competitive
interactions among trees and dispersal, with the Drossel-Schwabl forest fire
model, therefore representing fire in a spatially explicit manner. The model is
used to explore how the pattern of fire-spread, coupled with an explicit,
fire-vulnerable tree life stage, affects tree density and spatial pattern. Tree
density depends strongly on both fire frequency and tree-tree competition
although the fire frequency, which induces indirect interactions between trees
and between trees and grass, appears to be the crucial factor controlling the
tree-extinction transition in which the savanna becomes grassland. Depending on
parameters, adult trees may arrange in different regular or clumped patterns,
the later of two different types (compact or open). Cluster-size distributions
have fat tails but clean power-law behavior is only attained in specific cases.


title: Capacitance and charging of metallic objects

abstract:
  The capacitance of arbitrarily shaped objects is reformulated in terms of the
Neumann-Poincar\'{e} operator. Capacitance is simply the dielectric
permittivity of the surrounding medium multiplied by the area of the object and
divided by the squared norm of the Neumann-Poincar\'{e} eigenfunction that
corresponds to its largest eigenvalue. The norm of this eigenfunction varies
slowly with shape changes and allows perturbative calculations. This result is
also extended to capacitors. For axisymmetric geometries a numerical method
provides excellent results against finite element method results. Two
scale-invariant shape factors and the capacitance of nanowires and of membrane
in biological cells are discussed.


title: Dipole-dipole interaction in random electromagnetic fields

abstract:
  We demonstrate that a non-vanishing interaction force exists between pairs of
induced dipoles in random, statistically stationary electromagnetic field. This
new type of optical binding force leads to long-range interaction between
dipolar particles even when placed in spatially incoherent fields. We also
discuss several unique features of dipole-dipole interaction in spatially
incoherent Gaussian fields.


title: PIDE as front-end technology for Coq

abstract:
  Isabelle/PIDE is the current Prover IDE technology for Isabelle. It has been
developed in ML and Scala in the past 4-5 years for this particular proof
assistant, but with an open mind towards other systems. PIDE is based on an
asynchronous document model, where the prover receives edits continuously and
updates its internal state accordingly. The interpretation of edits and the
policies for proof document processing are determined by the prover. The editor
front-end merely takes care of visual rendering of formal document content.
  Here we report on an experiment to connect Coq to the PIDE infrastructure of
Isabelle. This requires to re-implement the core PIDE protocol layer of
Isabelle/ML in OCaml. The payload for semantic processing of proof document
content is restricted to lexical analysis in the sense of existing CoqIde
functionality. This is sufficient as proof-of-concept for PIDE connectivity.
Actual proof processing is then a matter of improving Coq towards timeless and
stateless proof processing, independently of PIDE technicalities. The
implementation worked out smoothly and required minimal changes to the refined
PIDE architecture of Isabelle2013.
  This experiment substantiates PIDE as general approach to prover interaction.
It illustrates how other provers of the greater ITP family can participate by
following similar reforms of the classic TTY loop as was done for Isabelle in
the past few years.


title: Robust 1-bit Compressive Sensing via Gradient Support Pursuit

abstract:
  This paper studies a formulation of 1-bit Compressed Sensing (CS) problem
based on the maximum likelihood estimation framework. In order to solve the
problem we apply the recently proposed Gradient Support Pursuit algorithm, with
a minor modification. Assuming the proposed objective function has a Stable
Restricted Hessian, the algorithm is shown to accurately solve the 1-bit CS
problem. Furthermore, the algorithm is compared to the state-of-the-art 1-bit
CS algorithms through numerical simulations. The results suggest that the
proposed method is robust to noise and at mid to low input SNR regime it
achieves the best reconstruction SNR vs. execution time trade-off.


title:
Completeness and related properties of the graph topology on function
  spaces

abstract:
  The graph topology $\tau_{\Gamma}$ is the topology on the space $C(X)$ of all
continuous functions defined on a Tychonoff space $X$ inherited from the
Vietoris topology on $X\times \mathbb R$ after identifying continuous functions
with their graphs. It is shown that all completeness properties between
complete metrizability and hereditary Baireness coincide for the graph topology
if and only if $X$ is countably compact; however, the graph topology is
$\alpha$-favorable in the strong Choquet game, regardless of $X$. Analogous
results are obtained for the fine topology on $C(X)$. Pseudocompleteness, along
with properties related to 1st and 2nd countability of $(C(X),\tau_{\Gamma})$
are also investigated.


title:
Strong Convergence of Wong-Zakai Approximations of Reflected SDEs in A
  Multidimensional General Domain

abstract:
  In this paper, we obtained the strong convergence of Wong-Zakai
approximations of reflected SDEs in a general multidimensional domain giving an
affirmative answer to the question posed in [ES].


title:
On natural deformations of symplectic automorphisms of manifolds of
  K3^[n] type

abstract:
  In the present paper we prove that finite symplectic groups of automorphisms
of manifolds of k3^[n] type can be obtained by deforming natural morphisms
arising from K3 surfaces if and only if they satisfy a certain numerical
condition.


title: Universal Longtime Dynamics in Dense Simple Fluids

abstract:
  There appears to be a longtime, very slowly evolving state in dense simple
fluids which, for high enough density, approaches a glassy nonergodic state.
The nature of the nonergodic state can be characterized by the associated
static equilibrium state. In particular, systems driven by Smoluchowski or
Newtonian dynamics share the same static equilibrium and nonergodic states.
That these systems share the same nonergodic states is a highly nontrivial
statement and requires establishing a number of results. In the high-density
regime one finds that an equilibrating system decays via a three-step process
identified in mode-coupling theory (MCT). For densities greater than a critical
density one has time-power-law decay with exponents a and b. There are sets of
linear fluctuation dissipation relations (FDRs) which connect the cumulants of
these two fields. The form of the FDRs is the same for both Smoluchowski or
Newtonian dynamics. While we show this universality of nonergodic states within
perturbation theory, we expect it to be true more generally.
  The nature of the approach to the nonergodic state has been suggested by MCT.
It has been a point of contention that MCT is a phenomenological theory and not
a systematic theory with prospects for improvement. Recently a systematic
theory has been developed. It naturally allows one to calculate
self-consistently density cumulants in a perturbation expansion in a
pseudo-potential. At leading order one obtains a kinetic kernel quadratic in
the density. This is a "one-loop" theory like MCT. At this one-loop level one
finds vertex corrections which depend on the three-point equilibrium cumulants.
Here we assume these vertex-corrections can be ignored and focus on the
higher-order loops. We show that one can sum up all of the loop contributions.
The higher-order loops do not change the nonergodic state parameters
substantially.


title: Bubble divergences and gauge symmetries in spin foams

abstract:
  Spin foams are candidate state-sum models for transition amplitudes in
quantum gravity. An active research subject is to identify the possible
divergences of spin foam models, or alternatively to show that models are
finite. We will discuss in detail the (non--occurrence of) divergences in the
Barrett-Crane model, formulated as an integral of delta function weights only.
We will furthermore present a simple method to estimate the divergence degree
of the so-called bubbles for general spin foam models. Divergences in spin
foams are expected to be related to the existence of gauge symmetries
(diffeomorphisms). Thus we have to conclude that such gauge symmetries are not
(fully) present in the model we consider. But we will identify a class of gauge
symmetries which occur at special solutions of the equations imposed by the
delta function weights. This situation is surprisingly similar to the case of
broken diffeomorphism symmetries in discrete gravity, which are present around
flat solutions. We introduce a method to derive (Ward-identity-like) equations
for the vertex amplitude of the model in the case of broken gauge symmetries.


title:
Coarse differentiation and quantitative nonembeddability for Carnot
  groups

abstract:
  We give lower bound estimates for the macroscopic scale of coarse
differentiability of Lipschitz maps from a Carnot group with the
Carnot-Carath\'{e}odory metric $(G,\dcc)$ to a few different classes of metric
spaces. Using this result, we derive lower bound estimates for quantitative
nonembeddability of Lipschitz embeddings of $G$ into a metric space $(X,d_X)$
if $X$ is either an Alexandrov space with nonpositive or nonnegative curvature,
a superreflexive Banach space, or another Carnot group that does not admit a
biLipschitz homomorphic embedding of $G$. For the same targets, we can further
give lower bound estimates for the biLipschitz distortion of every embedding $f
: B(n) \to X$, where B(n) is the ball of radius $n$ of a finitely generated
nonabelian torsion-free nilpotent group $G$. We also prove an analogue of
Bourgain's discretization theorem for Carnot groups and show that Carnot groups
have nontrivial Markov convexity. These give the first examples of metric
spaces that have nontrivial Markov convexity but cannot biLipschitzly embed
into Banach spaces of nontrivial Markov convexity.


title:
Broadband Epsilon-Near-Zero Metamaterials with Step-Like
  Metal-Dielectric Multilayer Structures

abstract:
  The concept of the broadband epsilon-near-zero meta-atom consisting of
layered stacks with specified metallic filling ratio and thickness is proposed
based on the Bergman spectral representation of the effective permittivity. The
step-like metal-dielectric multilayer structures are designed to achieve
realistic broadband epsilon-near-zero meta-atoms in optical frequency range.
These meta-atoms can be integrated as building blocks for unconventional
optical components with exotic electromagnetic properties over a wide frequency
range, such as the demonstrated broadband directional emission and phase front
shaping.


title: An Optimized Photon Pair Source for Quantum Circuits

abstract:
  We implement an ultrafast pulsed type-II parametric down conversion source in
a periodically poled KTP waveguide at telecommunication wavelengths with almost
identical properties between signal and idler. As such, our source resembles
closely a pure, genuine single mode photon pair source with indistinguishable
modes. We measure the joint spectral intensity distribution and second order
correlation functions of the marginal beams and find with both methods very low
effective mode numbers corresponding to a Schmidt number below 1.16. We further
demonstrate the indistinguishability as well as the purity of signal and idler
photons by Hong-Ou-Mandel interferences between signal and idler and between
signal/idler and a coherent field, respectively. Without using narrowband
spectral filtering, we achieve a visibility for the interference between signal
and idler of 94.8% and determine a purity of more than 80% for the heralded
single photon states. Moreover, we measure raw heralding efficiencies of 20.5%
and 15.5% for the signal and idler beams corresponding to detector-loss
corrected values of 80% and 70%.


title:
Spatially uniform single-qubit gate operations with near-field
  microwaves and composite pulse compensation

abstract:
  We present a microfabricated surface-electrode ion trap with a pair of
integrated waveguides that generate a standing microwave field resonant with
the 171Yb+ hyperfine qubit. The waveguides are engineered to position the wave
antinode near the center of the trap, resulting in maximum field amplitude and
uniformity along the trap axis. By calibrating the relative amplitudes and
phases of the waveguide currents, we can control the polarization of the
microwave field to reduce off-resonant coupling to undesired Zeeman sublevels.
We demonstrate single-qubit pi-rotations as fast as 1 us with less than 6 %
variation in Rabi frequency over an 800 um microwave interaction region. Fully
compensating pulse sequences further improve the uniformity of X-gates across
this interaction region.


title:
Analytical theory for the initial mass function: III time dependence and
  star formation rate

abstract:
  The present paper extends our previous theory of the stellar initial mass
function (IMF) by including the time-dependence, and by including the impact of
magnetic field. The predicted mass spectra are similar to the time independent
ones with slightly shallower slopes at large masses and peak locations shifted
toward smaller masses by a factor of a few. Assuming that star-forming clumps
follow Larson type relations, we obtain core mass functions in good agreement
with the observationally derived IMF, in particular when taking into account
the thermodynamics of the gas. The time-dependent theory directly yields an
analytical expression for the star formation rate (SFR) at cloud scales. The
SFR values agree well with the observational determinations of various Galactic
molecular clouds. Furthermore, we show that the SFR does not simply depend
linearly on density, as sometimes claimed in the literature, but depends also
strongly on the clump mass/size, which yields the observed scatter. We stress,
however, that {\it any} SFR theory depends, explicitly or implicitly, on very
uncertain assumptions like clump boundaries or the mass of the most massive
stars that can form in a given clump, making the final determinations uncertain
by a factor of a few. Finally, we derive a fully time-dependent model for the
IMF by considering a clump, or a distribution of clumps accreting at a constant
rate and thus whose physical properties evolve with time. In spite of its
simplicity, this model reproduces reasonably well various features observed in
numerical simulations of converging flows. Based on this general theory, we
present a paradigm for star formation and the IMF.


title: Explaining millimeter-sized particles in brown dwarf disks

abstract:
  Planets have been detected around a variety of stars, including low-mass
objects, such as brown dwarfs. However, such extreme cases are challenging for
planet formation models. Recent sub-millimeter observations of disks around
brown dwarf measured low spectral indices of the continuum emission that
suggest that dust grains grow to mm-sizes even in these very low mass
environments. To understand the first steps of planet formation in scaled-down
versions of T-Tauri disks, we investigate the physical conditions that can
theoretically explain the growth from interstellar dust to millimeter-sized
grains in disks around brown dwarf. We modeled the evolution of dust particles
under conditions of low-mass disks around brown dwarfs. We used coagulation,
fragmentation and disk-structure models to simulate the evolution of dust, with
zero and non-zero radial drift. For the non-zero radial drift, we considered
strong inhomogeneities in the gas surface density profile that mimic long-lived
pressure bumps in the disk. We studied different scenarios that could lead to
an agreement between theoretical models and the spectral slope found by
millimeter observations. We find that fragmentation is less likely and rapid
inward drift is more significant for particles in brown dwarf disks than in
T-Tauri disks. We present different scenarios that can nevertheless explain
millimeter-sized grains. As an example, a model that combines the following
parameters can fit the millimeter fluxes measured for brown dwarf disks: strong
pressure inhomogeneities of $\sim$ 40% of amplitude, a small radial extent
$\sim$ 15 AU, a moderate turbulence strength $\alpha_{\mathrm{turb}}= 10^{-3}$,
and average fragmentation velocities for ices $v_f = 10 m s^{-1}$.


title:
Deriving precise parameters for cool solar-type stars. Optimizing the
  iron line list

abstract:
  Temperature, surface gravity, and metallicitity are basic stellar atmospheric
parameters necessary to characterize a star. We aim to improve the description
of the spectroscopic temperatures especially for the cooler stars where the
differences with the Infrared Flux Method are higher, as presented in previous
work. Our spectroscopic analysis is based on the iron excitation and ionization
balance, assuming Kurucz model atmospheres in LTE. The abundance analysis is
determined using the code MOOG. We optimize the line list using a cool star
with high resolution and high signal-to-noise spectrum, as a reference in order
to check for weak, isolated lines. We test the quality of the new line list by
re-deriving stellar parameters for 451 stars with high resolution and
signal-to-noise HARPS spectra, that were analyzed in a previous work with a
larger line list. The comparison in temperatures between this work and the
latest IRFM shows that the differences for the cooler stars are significantly
smaller and more homogeneously distributed than in previous studies for stars
with temperatures below 5000 K. We use the new line list to re-derive
parameters for some of the cooler stars that host planets. Finally, we present
the impact of the new temperatures on the [Cr I/Cr II] and [Ti I/Ti II]
abundance ratios that previously showed systematic trends with temperature.


title:
Sharp local well-posedness of KdV type equations with dissipative
  perturbations

abstract:
  In this work, we study the initial value problems associated to some linear
perturbations of KdV equations. Our focus is in the well-posedness issues for
initial data given in the $L^2$-based Sobolev spaces. We derive bilinear
estimate in a space with weight in the time variable and obtain sharp local
well-posedness results.


title:
Homotopy theory of non-symmetric operads II: change of base category and
  left properness

abstract:
  We prove, under mild assumptions, that a Quillen equivalence between
symmetric monoidal model categories gives rise to a Quillen equivalence between
their model categories of (non-symmetric) operads, and also between model
categories of algebras over operads. We also show left properness results on
model categories of operads and algebras over operads. As an application, we
prove homotopy invariance for (unital) associative operads.


title: Random colorings and automorphism breaking in locally finite graphs

abstract:
  A colouring of a graph G is called distinguishing if its stabiliser in Aut G
is trivial. It has been conjectured that, if every automorphism of a locally
finite graph moves infinitely many vertices, then there is a distinguishing
2-colouring. We study properties of random 2-colourings of locally finite
graphs and show that the stabiliser of such a colouring is almost surely
nowhere dense in Aut G and a null set with respect to the Haar measure on the
automorphism group. We also investigate random 2-colourings in several classes
of locally finite graphs where the existence of a distinguishing 2-colouring
has already been established. It turns out that in all of these cases a random
2-colouring is almost surely distinguishing.


title:
Resampling Approach to the Estimation of the Aircraft Circulation Plan
  Reliability

abstract:
  The paper illustrates an application of the Resampling approach [2] for the
estimation of the aircraft circulation plan reliability. Resampling is an
intensive computer statistical method, which can be used effectively in the
case of small samples. Algorithm of the Resampling method for the given task is
illustrated and variance of obtained estimators is calculated, which is the
measure of the method effectiveness.


title:
Quark sector of S3 models: classification and comparison with
  experimental data

abstract:
  S3 models offer a low energy approach to describe the observed pattern of
masses and mixing, of both quarks and leptons. In this work, we first revisit
an S3 model with only one Higgs electroweak doublet, where the flavour symmetry
must be broken in order to produce an acceptable pattern of masses and mixing
for fermions. Then, we analyse different S3 models, where the flavour symmetry
is preserved as an exact, but hidden symmetry of the low energy spectra, after
the electroweak symmetry breaking. The latter models require the addition of
two more Higgs electroweak doublets which are accommodated in an S3 doublet. We
also explore the consequences of adding a fourth Higgs electroweak doublet,
thus occupying all three irreducible representations of S3. We show how the
various S3-invariant mass matrices of the different models can reproduce the
two texture zeroes and Nearest Neighbour Interaction matrix forms, which have
been found to provide a viable and universal treatment of mixing for both
quarks and leptons. We also find analytical and exact expressions for the CKM
matrix of the models in terms of quark mass ratios. Finally, we compare the
expressions of the CKM matrix of the different S3 models with the most up to
date values of masses and mixing in the quark sector, via a chi^2 analysis. We
find that the analytical expressions we derived reproduce remarkably well the
most recent experimental data of the CKM matrix, suggesting that S3 is a
symmetry of the quark sector.


title:
The microscopic phase density functional approach to the construction of
  the kinetic and hydrodynamic description for the system of self-propelled
  particles

abstract:
  We use the method of the microscopic phase density to get the kinetic
equation for the system of self-propelled particles with Vicsek-like alignment
rule. The hydrodynamic equations are derived for the ordered phase taking into
account the mean-field force only. The equation for the hydrodynamic velocity
plays the role of the Euler equation for the self-propelled Vicsek fluid. The
hydrodynamics of such ideal self-propelled fluid demonstrates the dynamical
transition from disordered initial state to the completely ordered motion. To
take the noise into account we consider how the framework of the local
equilibrium approximation affects the hydrodynamic equations and the viscous
tensor and show that in such approximation the shear viscosity vanishes.


title: Supersymmetric Optical Structures

abstract:
  We show that supersymmetry can provide a versatile platform in synthesizing a
new class of optical structures with desired properties and functionalities. By
exploiting the intimate relationship between superpatners, one can
systematically construct index potentials capable of exhibiting the same
scattering and guided wave characteristics. In particular, in the Helmholtz
regime, we demonstrate that one-dimensional supersymmetric pairs display
identical reflectivities and transmittivities for any angle of incidence.
Optical SUSY is then extended to two-dimensional systems where a link between
specific azimuthal mode subsets is established. Finally we explore
supersymmetric photonic lattices where discreteness can be utilized to design
lossless integrated mode filtering arrangements.


title:
Topological effects and particle-physics analogies beyond the massless
  Dirac-Weyl fermion in graphene nanorings

abstract:
  Armchair and zigzag edge terminations in planar hexagonal and trigonal
graphene nanorings are shown to underlie one-dimensional topological states
associated with distinctive energy gaps and patterns (e.g., linear dispersion
of the energy of an hexagonal ring with an armchair termination versus
parabolic dispersion for a zigzag terminated one) in the bands of the
tight-binding spectra as a function of the magnetic field. A relativistic
Dirac-Kronig-Penney model analysis of the tight-binding Aharonov-Bohm behavior
reveals that the graphene quasiparticle in an armchair hexagonal ring is a
condensed-matter realization of an ultrarelativistic fermion with a
position-dependent mass term, akin to the zero-energy fermionic solitons with
fractional charge familiar from quantum field theory and from the theory of
polyacetylene. The topological origins of the above behavior are highlighted by
contrasting it with the case of a trigonal armchair ring, where we find that
the quasiparticle excitations behave as familiar Dirac fermions with a constant
mass. Furthermore, the spectra of a zigzag hexagonal ring correspond to the
low-kinetic-energy nonrelativistic regime of a leptonlike massive fermion. A
onedimensional relativistic Lagrangian formalism coupling a fermionic and a
scalar bosonic field via a Yukawa interaction, in conjunction with the breaking
of the Z2 reflectional symmetry of the scalar field, is shown to unify the
above dissimilar behaviors.


title:
The drastic outcomes from voting alliances in three-party bottom-up
  democratic voting (1990 $\rightarrow$ 2013)

abstract:
  The drastic effect of local alliances in three-party competition is
investigated in democratic hierarchical bottom-up voting. The results are
obtained analytically using a model which extends a sociophysics frame
introduced in 1986 \cite{psy} and 1990 \cite{lebo} to study two-party systems
and the spontaneous formation of democratic dictatorship. It is worth stressing
that the 1990 paper was published in the Journal of Statistical Physics, the
first paper of its kind in the journal. It was shown how a minority in power
can preserve its leadership using bottom-up democratic elections. However such
a bias holds only down to some critical value of minimum support. The results
were used latter to explain the sudden collapse of European communist parties
in the nineties. The extension to three-party competition reveals the
mechanisms by which a very small minority party can get a substantial
representation at higher levels of the hierarchy when the other two competing
parties are big. Additional surprising results are obtained, which enlighten
the complexity of three-party democratic bottom-up voting. In particular, the
unexpected outcomes of local voting alliances are singled out. Unbalanced
democratic situations are exhibited with strong asymmetries between the actual
bottom support of a party and its associated share of power at the top
leadership. Subtle strategies are identified for a party to maximize its hold
on the top leadership. The results are also valid to describe opinion dynamics
with three competing opinions.


title: H\"older equivalence of the value function for control-affine systems

abstract:
  We prove the continuity and the H\"older equivalence w.r.t.\ an Euclidean
distance of the value function associated with the $L^1$ cost of the
control-affine system $\dot q = \drift(q)+\sum_{j=1}^m u_j f_j(q)$, satisfying
the strong H\"ormander condition. This is done by proving a result in the same
spirit as the Ball-Box theorem for driftless (or sub-Riemannian) systems. The
techniques used are based on a reduction of the control-affine system to a
linear but time-dependent one, for which we are able to define a generalization
of the nilpotent approximation and through which we derive estimates for the
shape of the reachable sets. Finally, we also prove the continuity of the value
function associated with the $L^1$ cost of time-dependent systems of the form
$\dot q = \sum_{j=1}^m u_j f_j^t(q)$.


title:
A minimal interface problem arising from a two component Bose Einstein
  condensate via $\G$-convergence

abstract:
  We consider the energy modeling a two component Bose-Einstein condensate in
the limit of strong coupling and strong segregation. We prove the
$\Gamma$-convergence to a perimeter minimization problem, with a weight given
by the density of the condensate. In the case of equal mass for the two
components, this leads to symmetry breaking for the ground state. The proof
relies on a new formulation of the problem in terms of the total density and
spin functions, which turns the energy into the sum of two weighted
Cahn-Hilliard energies. Then, we use techniques coming from geometric measure
theory to construct upper and lower bounds. In particular, we make use of the
slicing technique introduced in Ambrosio-Tororelli (CPAM, 1990).


title:
Well-posedness of the Stokes-Coriolis system in the half-space over a
  rough surface

abstract:
  This paper is devoted to the well-posedness of the stationary $3$d
Stokes-Coriolis system set in a half-space with rough bottom and Dirichlet data
which does not decrease at space infinity. Our system is a linearized version
of the Ekman boundary layer system. We look for a solution of infinite energy
in a space of Sobolev regularity. Following an idea of G\'erard-Varet and
Masmoudi, the general strategy is to reduce the problem to a bumpy channel
bounded in the vertical direction thanks a transparent boundary condition
involving a Dirichlet to Neumann operator. Our analysis emphasizes some strong
singularities of the Stokes-Coriolis operator at low tangential frequencies.
One of the main features of our work lies in the definition of a Dirichlet to
Neumann operator for the Stokes-Coriolis system with data in the Kato space
$H^{1/2}_{uloc}$.


title:
Fabrication and modeling of piezoelectric transducers for High-Frequency
  medical imaging

abstract:
  We have studied the processing of piezoelectric thick films using
electrophoretic deposition (EPD) for high-frequency ultrasound applications.
Lead-zirconium-titanate (PZT) particles synthetized by solid states synthesis
were dispersed in ethanol using ammonium polyacrylate (PAA). The
electrophoretic deposition of PZT particles was performed at a constant-current
mode. PZT thick-films deposited at 1 mA for 60 seconds were sintered at 900oC
for 2 hours in a PbO-controlled atmosphere. The scanning-electron microscopy
(SEM) analysis shows that the thickness of PZT layer is uniform and that the
pores are homogeneously distributed within the layer. The complex electrical
impedance was measured and fitted by KLM scheme in order to deduce the
dielectric, mechanical and piezoelectric parameters of the thick-films. The
density and thickness of PZT thick films are used as inputs and the thickness
coupling factor kt, dielectric constant at constant strain and resonant
frequency are deduced. The results show that homogeneous PZT thick-film
structures with tailored thickness and density prepared by EPD and sintering
having a resonant frequency around 20 MHz can be used for noninvasive medical
ultrasound imaging and diagnostics.


title:
Onsager phase factor of quantum oscillations in the organic metal
  theta-(BEDT-TTF)4CoBr4(C6H4Cl2)

abstract:
  De Haas-van Alphen oscillations are studied for Fermi surfaces illustrating
the Pippard's model, commonly observed in multiband organic metals. Field- and
temperature-dependent amplitude of the various Fourier components, linked to
frequency combinations arising from magnetic breakdown between different bands,
are considered. Emphasis is put on the Onsager phase factor of these
components. It is demonstrated that, in addition to the usual Maslov index,
field-dependent phase factors must be considered to precisely account for the
data at high magnetic field. We present compelling evidence of the existence of
such contributions for the organic metal theta-(BEDT-TTF)4CoBr4(C6H4Cl2).