title:
Radiative Branching Ratios for Excited States of $^{174}$YbF:
  Application to Laser Cooling

abstract:
  We excite YbF molecules to low-lying vibrational levels of the $A^2\Pi_{1/2}$
state, and of the nearby perturber state sometimes called [18.6]0.5. By
dispersing the fluorescence, we measure branching ratios for the radiative
decay to vibrational levels of the $X^2\Sigma^+$ state. These ratios help to
determine the optimum laser cooling scheme for the molecule. Our results
establish the practicality of a scheme that was previously suggested [Tarbutt
et al., New J. Phys. 15 (2013) 053034] and show how the scheme can be modified
to provide a stronger radiative cooling force.


title: Estimation in a change-point nonlinear quantile model

abstract:
  This paper considers a nonlinear quantile model with change-points. The
quantile estimation method, which as a particular case includes median model,
is more robust with respect to other traditional methods when model errors
contain outliers. Under relatively weak assumptions, the convergence rate and
asymptotic distribution of change-point and of regression parameter estimators
are obtained. Numerical study by Monte Carlo simulations shows the performance
of the proposed method for nonlinear model with change-points.


title: Set Stabilizability of Quantum Systems

abstract:
  We explore set-stabilizability by constrained controls, and both
controllability and stabilizability can be regarded as the special case of
set-stabilizability. We not only clarify how to define an equilibrium point of
Schr$\ddot{o}$dinger Equations, but also establish the necessary and sufficient
conditions for stabilizability of quantum systems. Unfortunately, it is
revealed that the necessary conditions are quite strict for stabilizability of
some concrete quantum systems like nuclear spin systems, and this further
justifies the introduction of set-stabilizability notion. It is also
exemplified that set-stabilizability can be used for investigating quantum
information processing problems including quantum information storage and
entangled states generation.


title:
Negative Orlicz-Sobolev norms and strongly nonlinear systems in fluid
  mechanics

abstract:
  We prove a version of the negative norm theorem in Orlicz-Sobolev spaces. A
study of continuity properties of the Bogovskii -operator between Orlicz spaces
is a crucial step, of independent interest, in our approach. Applications to
the problem of pressure reconstruction for Non-Newtonian fluids governed by
constitutive laws, which are not necessarily power type, are presented. A key
inequality for a numerical analysis of the underlying elliptic system is also
derived.


title: Crystal phases of soft spheres systems in a slab geometry

abstract:
  We have identified the ground state configurations of soft particles
(interacting via inverse power potentials) confined between two hard,
impenetrable walls. To this end we have used a highly reliable optimization
scheme at {\it vanishing} temperature while varying the wall separation over a
representative range. Apart from the expected layered triangular and square
structures (which are compatible with the three dimensional bulk fcc lattice),
we have identified a cascade of highly complex intermediate structures. Taking
benefit of the general scaling properties of inverse power potentials, we could
identify -- for a given softness value -- one single master curve which relates
the energy to the wall separation, irrespective of the density of the system.
Via extensive Monte Carlo simulations, we have performed closer investigations
of these intermediate structures at {\it finite} temperature: we could provide
evidence to which extent these particle arrangements remain stable over a
relatively large temperature range.


title: On Convergence in the Spatial AK Growth Models

abstract:
  Recent research in economic theory attempts to study optimal economic growth
and spatial location of economic activity in a unified framework. So far, the
key result of this literature - asymptotic convergence, even in the absence of
decreasing returns to capital - relies on specific assumptions about the
objective of the social planner. We show that this result does not depend on
such restrictive assumptions and obtains for a broader class of objective
functions. We also generalize this finding, allowing for the time-varying
technology parameter, and provide an explicit solution for the dynamics of
spatial distribution of the capital stock.


title: Comment on "Asking Photons Where Have They Been"

abstract:
  We argue that, in the recent letter by A. Danan et al. [PRL 111, 240402
(2013), arXiv:1304.7469], if weak measurements are performed such that complete
destructive interference is not disturbed, claims such as "some photons have
been inside the inner interferometer but they never entered and never left"
should not arise. Standard quantum mechanics not only explains the physics
better than the two-state vector formulation the authors advocate, but it can
tell a very different story.


title: The Abelian Higgs model and a minimal length in an un-particle scenario

abstract:
  We consider both the Abelian Higgs model and the impact of a minimal length
in the un-particle sector. It is shown that even if the Higgs field takes a
non-vanishing v.e.v., gauge interaction keeps its long range character leading
to an effective gauge symmetry restoration. The effect of a quantum gravity
induced minimal length on a physical observable is then estimated by using a
physically-based alternative to the usual Wilson loop approach. Interestingly,
we obtain an ultraviolet finite interaction energy described by a confluent
hyper-geometric function, which shows a remarkable richness of behavior.


title:
Damped solitons in an extended nonlinear Schrodinger equation with a
  spatial stimulated Raman scattering and decreasing dispersion

abstract:
  Dynamics of solitons is considered in the framework of an extended nonlinear
Schrodinger equation (NLSE), which is derived from a system of the Zakharov's
type for the interaction between high- and low-frequency (HF and LF) waves. The
resulting NLSE includes a pseudo-stimulated-Raman-scattering (pseudo-SRS) term,
i.e., a spatial-domain counterpart of the SRS term, which is a known ingredient
of the temporal-domain NLSE in optics. Also included is inhomogeneity of the
spatial second-order dispersion (SOD) and linear losses of HF waves. It is
shown that wavenumber downshift by the pseudo-SRS may be compensated by upshift
provided by SOD whose local strength is an exponentially decaying function of
the coordinate. An analytical soliton solution with a permanent shape is found
in an approximate form, and is verified by comparison with numerical results


title:
The Design of a Network-On-Chip Architecture Based On An Avionic
  Protocol

abstract:
  When the Network-On-Chip (NoC) paradigm was introduced, many researchers have
proposed many novelistic NoC architectures, tools and design strategies. In
this paper we introduce a new approach in the field of designing
Network-On-Chip (NoC). Our inspiration came from an avionic protocol which is
the AFDX protocol. The proposed NoC architecture is a switch centric
architecture, with exclusive shortcuts between hosts and utilizes the
flexibility, the reliability and the performances offered by AFDX.


title:
The relation between cross-section, decay width and imaginary potential
  of heavy quarkonium in a quark-gluon plasma

abstract:
  Heavy quarkonium suppression was proposed long ago as a signal of the
formation of a deconfined phase in heavy ion collisions. Originally the
mechanism responsible for this suppression was thought to be color screening.
However perturbative computations and recent lattice studies suggest the
existence of an imaginary part of the potential which could have a more
important role for suppression than screening. In this work we review some
general aspects of effective field theories for heavy quarkonium in the medium
and discuss the physical phenomena behind the imaginary part of the potential
and the decay width of heavy quarkonium and their corresponding cross sections.


title:
Mass-loss histories of Type IIn supernova progenitors within decades
  before their explosion

abstract:
  We present results of a systematic study of the mass-loss properties of Type
IIn supernova progenitors within decades before their explosion. We apply an
analytic light curve model to 11 Type IIn supernova bolometric light curves to
derive the circumstellar medium properties. We reconstruct the mass-loss
histories based on the estimated circumstellar medium properties. The estimated
mass-loss rates are mostly higher than 1e-3 Msun/yr and they are consistent
with those obtained by other methods. The mass-loss rates are often found to be
constantly high within decades before their explosion. This indicates that
there exists some mechanism to sustain the high mass-loss rates of Type IIn
supernova progenitors for at least decades before their explosion. Thus, the
shorter eruptive mass loss events observed in some Type IIn supernova
progenitors are not always responsible for creating their dense circumstellar
media. In addition, we find that Type IIn supernova progenitors may tend to
increase their mass-loss rates as they approach to the time of their explosion.
We also show a detailed comparison between our analytic prediction and
numerical results.


title: Azimuthally sensitive femtoscopy in event-by-event hydrodynamics

abstract:
  We analyze the pion femtoscopy correlations in noncentral Au-Au and Pb-Pb
collisions. The azimuthally sensitive Hanbury Brown-Twiss (HBT) method is used
to extract the interferometry radii depending on the azimuthal angle with
respect to the second and third-order event plane. The results are in
semiquantitative agreement with the STAR collaboration data on the HBT radii
with respect to the second-order reaction plane, with the preliminary PHENIX
collaboration data on the HBT radii with respect to the third-order reaction
plane in Au-Au collisions at 200GeV, and with the preliminary ALICE
collaboration data for the HBT radii with respect to the second-order event
plane for Pb-Pb collisions at 2.76TeV.


title:
Could time-symmetric interactions reconcile relativity and quantum
  non-locality?

abstract:
  We present a simple model demonstrating that time-symmetric relativistic
interactions can account for correlations violating the Bell inequalities while
avoiding conspiracies as well as the commitment to instantaneous influences.
Based on an explicit statistical analysis of this model, we emphasize the
essential virtues and problems of such an account and discuss its relation to
Bell's theorem.


title:
Goodness-of-fit for log-linear network models: Dynamic Markov bases
  using hypergraphs

abstract:
  Social networks and other large sparse data sets pose significant challenges
for statistical inference, as many standard statistical methods for testing
model fit are not applicable in such settings. Algebraic statistics offers a
theoretically justified approach to goodness-of-fit testing that relies on the
theory of Markov bases and is intimately connected with the geometry of the
model as described by its fibers.
  Most current practices require the computation of the entire basis, which is
infeasible in many practical settings. We present a dynamic approach to explore
the fiber of a model, which bypasses this issue, and is based on the
combinatorics of hypergraphs arising from the toric algebra structure of
log-linear models.
  We demonstrate the approach on the Holland-Leinhardt $p_1$ model for random
directed graphs that allows for reciprocated edges.


title:
Total and Partial Fragmentation Cross-Section of 500 MeV/nucleon Carbon
  Ions on Different Target Materials

abstract:
  By using an experimental setup based on thin and thick double-sided
microstrip silicon detectors, it has been possible to identify the
fragmentation products due to the interaction of very high energy primary ions
on different targets. Here we report total and partial cross-sections measured
at GSI (Gesellschaft fur Schwerionenforschung), Darmstadt, for 500 MeV/n energy
$^{12}C$ beam incident on water (in flasks), polyethylene, lucite, silicon
carbide, graphite, aluminium, copper, iron, tin, tantalum and lead targets. The
results are compared to the predictions of GEANT4 (v4.9.4) and FLUKA (v11.2)
Monte Carlo simulation programs.


title: Isometries of Minkowski geometries

abstract:
  In this paper we review the known facts on isometries of Minkowski geometries
and prove some new results on them. We give the normal forms of two special
classes of operators and also characterize the isometry group of Minkowski
$3$-spaces in which the unit sphere does not contain an ellipse.


title:
On distinguishing of non-signaling boxes via completely locality
  preserving operations

abstract:
  We consider discriminating between bipartite boxes with 2 binary inputs and 2
binary outputs (2x2) using the class of completely locality preserving
operations i.e. those, which transform boxes with local hidden variable model
(LHVM) into boxes with LHVM, and have this property even when tensored with
identity operation. Following approach developed in entanglement theory we
derive linear program which gives an upper bound on the probability of success
of discrimination between different isotropic boxes. In particular we provide
an upper bound on the probability of success of discrimination between
isotropic boxes with the same mixing parameter. As a counterpart of
entanglement monotone we use the non-locality cost. Discrimination is
restricted by the fact that non-locality cost does not increase under
considered class of operations. We also show that with help of allowed class of
operations one can distinguish perfectly any two extremal boxes in 2x2 case and
any local extremal box from any other extremal box in case of two inputs and
two outputs of arbitrary cardinalities.


title: Gluon propagator with dynamical quarks

abstract:
  We review recent work on the effects of quark loops on the gluon propagator
in the Landau gauge, relying mainly on the Schwinger-Dyson equations that
describe the two-point sector of QCD. Particularly important in this context is
the detailed study of how the standard gluon mass generation mechanism, which
is responsible for the infrared finiteness of the quenched gluon propagator, is
affected by the inclusions of dynamical quarks. This issue is especially
relevant and timely, given the qualitative picture that emerges from recent
unquenched lattice simulations. Our results demonstrate clearly that the gluon
mass generation persists, and that the corresponding saturation points of the
unquenched gluon propagators are progressively suppressed, as the number of
quark flavors increases.


title:
Open spin chains with generic integrable boundaries: Baxter equation and
  Bethe ansatz completeness from SOV

abstract:
  We solve the longstanding problem to define a functional characterization of
the spectrum of the transfer matrix associated to the most general spin-1/2
representations of the 6-vertex reflection algebra for general inhomogeneous
chains. The corresponding homogeneous limit reproduces the spectrum of the
Hamiltonian of the spin-1/2 open XXZ and XXX quantum chains with the most
general integrable boundaries. The spectrum is characterized by a second order
finite difference functional equation of Baxter type with an inhomogeneous term
which vanishes only for some special but yet interesting non-diagonal boundary
conditions. This functional equation is shown to be equivalent to the known
separation of variable (SOV) representation hence proving that it defines a
complete characterization of the transfer matrix spectrum. The polynomial
character of the Q-function allows us then to show that a finite system of
equations of generalized Bethe type can be similarly used to describe the
complete transfer matrix spectrum.

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


title:
Electroweak and Higgs Measurements Using Tau Final States with the LHCb
  Detector

abstract:
  Spin correlations for tau lepton decays are included in the Pythia 8 event
generation software and the spin correlations for the decays of tau leptons
produced from electroweak and Higgs bosons are calculated. Decays of the tau
lepton using sophisticated resonance models are included in Pythia 8 for all
channels with experimentally observed branching fractions greater than 0.04%.
The mass distributions for the decay products of these channels are validated
and the technical implementation of these decays is described.
  A measurement of the inclusive Z to di-tau cross-section using 1.0 inverse fb
of data from pp collisions at sqrt(s) = 7 TeV collected with the LHCb detector
is presented. Reconstructed final states containing two muons, a muon and an
electron, a muon and a charged hadron, or an electron and a charged hadron are
selected as candidates. The cross-section for Z bosons with a mass between 60
and 120 GeV decaying into tau leptons with pseudo-rapidities between 2.0 and
4.5 and transverse momenta greater than 20 GeV is measured to be 72.3 +- 3.5 +-
2.9 +- 2.5 pb. The first uncertainty is statistical, the second uncertainty is
systematic, and the third is to due the integrated luminosity uncertainty.
  Limits on the production of neutral Higgs bosons decaying into tau lepton
pairs with pseudo-rapidities between 2.0 and 4.5 are set at a 95% confidence
level using the same LHCb dataset. A model independent upper limit on the
production of neutral Higgs bosons decaying into tau leptons is set and ranges
between 8.6 pb for a Higgs boson mass of 90 GeV to 0.7 pb for a Higgs boson
mass of 250 GeV. An upper limit on tan-beta in the CP-odd Higgs mass and
tan-beta plane is set for the mh-max scenario of the minimal supersymmetric
model and varies from 34 for a CP-odd Higgs boson mass of 90 GeV to 70 for a
CP-odd Higgs boson mass of 140 GeV.


title:
Elemental Abundance Analysis of the Early Type Members of the Open
  Cluster M6: Preliminary Results

abstract:
  Differences in chemical composition among main sequence stars within a given
cluster are probably due to differences in their masses and other effects such
as radiative diffusion, magnetic field, rotation, mixing mechanisms, mass loss,
accretion and multiplicity. The early type main-sequence members of open
clusters of different ages allow to study the competition between radiative
diffusion and mixing mechanisms. We have analysed low and high resolution
spectra covering the spectral range 4500 - 5840 Angs. of late B, A, and F type
members of the open Cluster M6 (age about 100 Myr). The spectra were obtained
using the FLAMES/GIRAFFE spectrograph mounted at UT2, the 8 meter class VLT
telescope. The effective temperatures, surface gravities and microturbulent
velocities of the stars were derived using both photometric and spectral
methods. We have also performed a chemical abundance analysis using synthetic
spectra. The abundances of the elements were determined for C, O, Mg, Si, Ca,
Sc, Ti, Cr, Mn, Fe, Ni, Y, Ba. The star-to-star variations in elemental
abundances among the members of the open cluster M6 were discussed.


title:
Prediction of non-identical particle correlations for the Beam Energy
  Scan program

abstract:
  Femtoscopy of two non-identical particles in heavy ion collisions enables one
to study the space-time asymmetry in the particle's emission process.
Theoretical studies based on EPOS model performed for collision energies from
the Beam Energy Scan program in STAR allow us to investigate the dependence of
source sizes and dynamics effects. Obtained information will enable us to
predict the collective behaviour of femtoscopic particle's source.


title: Three planetary companions around M67 stars

abstract:
  For the past six years we have carried out a search for massive planets
around main sequence and evolved stars in the open cluster (OC) M67, using
radial velocity (RV) measurements obtained with HARPS at ESO (La Silla), SOPHIE
at OHP and HRS at HET. Additional RV data come from CORALIE at the Euler Swiss
Telescope. We aim to perform a long-term study on giant planet formation in
open clusters and determine how it depends on stellar mass and chemical
composition.
  We report the detection of three new extrasolar planets: two in orbit around
the two G dwarfs YBP1194 and YBP1514, and one around the evolved star S364. The
orbital solution for YBP1194 yields a period of 6.9 days, an eccentricity of
0.24, and a minimum mass of 0.34 Mj. YBP1514 shows periodic RV variations of
5.1 days, a minimum mass of 0.40 Mj, and an eccentricity of 0.39. The best
Keplerian solution for S364 yields a period of 121.7 days, an eccentricity of
0.35 and a minimum mass of 1.54 Mj. An analysis of H_alpha core flux
measurements as well as of the line bisectors spans revealed no correlation
with the RV periods, indicating that the RV variations are best explained by
the presence of a planetary companion. Remarkably, YBP1194 is one of the best
solar twins identified so far, and YBP1194b is the first planet found around a
solar twin that belongs to a stellar cluster. In contrast with early reports
and in agreement with recent findings, our results show that massive planets
around stars of open clusters are as frequent as those around field stars.


title: QCD phase transition with a power law chameleon scalar field in the bulk

abstract:
  In this work, a brane world model with a perfect fluid on brane and a scalar
field on bulk has been used to study quark-hadron phase transition. The bulk
scalar field has an interaction with brane matter. This interaction comes into
non-conservation relation which describe an energy transfer between bulk and
brane. Since quark-hadron transition curly depends on the form of evolution
equations therefore modification of energy conservation equation and Friedmann
equation comes into some interesting results about the time of transition. The
evolution of physical quantities relevant to quantitative of early times namely
energy density $\rho$ temperature $T$ and scale factor $a$ have been considered
utilizing two formalisms as crossover formalism and first order phase
transition formalism. The results show that the quark-hadron phase transition
in occurred about nanosecond after big bang and the general behavior
temperature is similar in both of two formalism.


title:
Impact of Transceiver Power Consumption on the Energy Efficiency of
  Zero-Forcing Detector in Massive MIMO Systems

abstract:
  We consider the impact of transceiver power consumption on the energy
efficiency (EE) of the Zero Forcing (ZF) detector in the uplink of massive MIMO
systems, where a base station (BS) with $M$ antennas communicates coherently
with $K$ single antenna user terminals (UTs). We consider the problem of
maximizing the EE with respect to (M,K) for a fixed sum spectral efficiency.
Through analysis we study the impact of system parameters on the optimal EE.
System parameters consists of the average channel gain to the users and the
power consumption parameters (PCPs) (e.g., power consumed by each RF
antenna/receiver at BS). When the average user channel gain is high or else the
BS/UT design is power inefficient, our analysis reveals that it is optimal to
have a few BS antennas and a single user, i.e., non-massive MIMO regime.
Similarly, when the channel gain is small or else the BS/UT design is power
efficient, it is optimal of have a larger (M,K), i.e., massive MIMO regime.
Tight analytical bounds on the optimal EE are proposed for both these regimes.
The impact of the system parameters on the optimal EE is studied and several
interesting insights are drawn.


title: Heralded Quantum Entanglement between Distant Matter Qubits

abstract:
  We propose a scheme to realize heralded quantum entanglement between two
distant matter qubits using two $\Lambda$ atom systems. Our proposal does not
need any photon interference. We also present a general theory of outcome state
of non-monochromatic incident light and finite interaction time.


title: Mesogranulation and small-scale dynamo action in the quiet Sun

abstract:
  Regions of quiet Sun generally exhibit a complex distribution of small-scale
magnetic field structures, which interact with the near-surface turbulent
convective motions. Furthermore, it is probable that some of these magnetic
fields are generated locally by a convective dynamo mechanism. In addition to
the well-known granular and supergranular convective scales, various
observations have indicated that there is an intermediate scale of convection,
known as mesogranulation, with vertical magnetic flux concentrations
accumulating preferentially at mesogranular boundaries. Our aim is to
investigate the small-scale dynamo properties of a convective flow that
exhibits both granulation and mesogranulation, comparing our findings with
solar observations. Adopting an idealised model for a localised region of quiet
Sun, we use numerical simulations of compressible magnetohydrodynamics, in a 3D
Cartesian domain, to investigate the parametric dependence of this system
(focusing particularly upon the effects of varying the aspect ratio and the
Reynolds number). In purely hydrodynamic convection, we find that
mesogranulation is a robust feature of this system provided that the domain is
wide enough to accommodate these large-scale motions. The mesogranular peak in
the kinetic energy spectrum is more pronounced in the higher Reynolds number
simulations. We investigate the dynamo properties of this system in both the
kinematic and the nonlinear regimes and we find that the dynamo is always more
efficient in larger domains, when mesogranulation is present. Furthermore, we
use a filtering technique in Fourier space to demonstrate that it is indeed the
larger scales of motion that are primarily responsible for driving the dynamo.
In the nonlinear regime, the magnetic field distribution compares very
favourably to observations, both in terms of the spatial distribution and the
measured field strengths.


title: A distance on curves modulo rigid transformations

abstract:
  We propose a geometric method for quantifying the difference between
parametrized curves in Euclidean space by introducing a distance function on
the space of parametrized curves up to rigid transformations (rotations and
translations). Given two curves, the distance between them is defined as the
infimum of an energy functional which, roughly speaking, measures the extent to
which the jet field of the first curve needs to be rotated to match up with the
jet field of the second curve. We show that this energy functional attains a
global minimum on the appropriate function space, and we derive a set of
first-order ODEs for the minimizer.


title: The abstract Lewy-Stampacchia inequality and applications

abstract:
  We prove an abstract and general version of the Lewy-Stampacchia inequality.
We then show how to reproduce more classical versions of it and, more
importantly, how it can be used in conjunction with Laplacian comparison
estimates to produce large class of functions with bounded Laplacian on spaces
with a lower bound on the Ricci curvature.


title:
An Importance Sampling Scheme on Dual Factor Graphs. I. Models in a
  Strong External Field

abstract:
  We propose an importance sampling scheme to estimate the partition function
of the two-dimensional ferromagnetic Ising model and the two-dimensional
ferromagnetic $q$-state Potts model, both in the presence of an external
magnetic field. The proposed scheme operates in the dual Forney factor graph
and is capable of efficiently computing an estimate of the partition function
under a wide range of model parameters. In particular, we consider models that
are in a strong external magnetic field.

categories: stat.CO cond-mat.stat-mech cs.IT math.IT


title: Communication on structure of biological networks

abstract:
  Networks are widely used to represent interaction pattern among the
components in complex systems. Structures of real networks from differ- ent
domains may vary quite significantly. Since there is an interplay be- tween
network architecture and dynamics, structure plays an important role in
communication and information spreading on a network. Here we investigate the
underlying undirected topology of different biological networks which support
faster spreading of information and are better in communication. We analyze the
good expansion property by using the spectral gap and communicability between
nodes. Different epidemic models are also used to study the transmission of
information in terms of disease spreading through individuals (nodes) in those
networks. More- over, we explore the structural conformation and properties
which may be responsible for better communication. Among all biological
networks studied here, the undirected structure of neuronal networks not only
pos- sesses the small-world property but the same is expressed remarkably to a
higher degree than any randomly generated network which possesses the same
degree sequence. A relatively high percentage of nodes, in neuronal networks,
form a higher core in their structure. Our study shows that the underlying
undirected topology in neuronal networks is significantly qualitatively
different than the same from other biological networks and that they may have
evolved in such a way that they inherit a (undirected) structure which is
excellent and robust in communication.


title: Magnetic Properties and Large Coercivity of MnxGa Nanostructures

abstract:
  To investigate structure-property correlations, high-coercivity MnxGa
nanoparticles were synthesized by the method of sequential deposition of Ga and
Mn fluxes using molecular beam epitaxy. Spontaneous nanostructuring was
assisted by the use of an Au precursor and thermal annealing, and the growth
properties, structure and magnetic properties were characterized. Atomic force
microscopy revealed average particle dimensions of 100 nm and X-ray diffraction
revealed a dominant tetragonal D022 crystal structures. Magnetic
characterization at room temperature identified the presence of two magnetic
phases, dominated by a high-coercivity (2.3 T) component in addition to a
low-coercivity component.


title: Check of reality for complex algebraic functions

abstract:
  Consider a real algebraic curve with set of real points $R\neq\emptyset$ and
complexification $P\supset R$. Let $f$ be an algebraic function on $P$ with
devisor of critical points $D\subset P$. We prove that $f$ is real after a
linear-factorial transformation, if $D$ is symmetrical with respect to $R$ and
$f(p)=f(p')$ for symmetrical points $p,p'\in D$. In particulary, this gives a
proof of Boris and Michael Shapiro conjecture (2002).


title:
Optical Absorption Measurement at 1550 nm on a Highly-Reflective
  Si/SiO$_2$ Coating Stack

abstract:
  Future laser-interferometric gravitational wave detectors (GWDs) will
potentially employ test mass mirrors from crystalline silicon and a laser
wavelength of $1550\,\rm{nm}$, which corresponds to a photon energy below the
silicon bandgap. Silicon might also be an attractive high-refractive index
material for the dielectric mirror coatings. Films of amorphous silicon (a-Si),
however, have been found to be significantly more absorptive at $1550\,\rm{nm}$
than crystalline silicon (c-Si). Here, we investigate the optical absorption of
a Si/SiO$_2$ dielectric coating produced with the ion plating technique. The
ion plating technique is distinct from the standard state-of-the-art ion beam
sputtering technique since it uses a higher processing temperature of about
250$^\circ$C, higher particle energies, and generally results in higher
refractive indices of the deposited films. Our coating stack was fabricated for
a reflectivity of $R=99.95\,\%$ for s-polarized light at $1550\,\rm{nm}$ and
for an angle of incidence of 44$^\circ$. We used the photothermal self-phase
modulation technique to measure the coating absorption in s-polarization and
p-polarization. We obtained $\alpha^{\rm coat}_{s}=(1035 \pm 42)\,\rm{ppm}$ and
$\alpha^{\rm coat}_{p}=(1428 \pm 97)\,\rm{ppm}$. These results correspond to an
absorption coefficient which is lower than literature values for a-Si which
vary from $100\,\rm{/cm}$ up to $2000\,\rm{/cm}$. It is, however, still orders
of magnitude higher than expected for c-Si and thus still too high for GWD
applications.


title: Spoiled Onions: Exposing Malicious Tor Exit Relays

abstract:
  Several hundred Tor exit relays together push more than 1 GiB/s of network
traffic. However, it is easy for exit relays to snoop and tamper with
anonymised network traffic and as all relays are run by independent volunteers,
not all of them are innocuous.
  In this paper, we seek to expose malicious exit relays and document their
actions. First, we monitored the Tor network after developing a fast and
modular exit relay scanner. We implemented several scanning modules for
detecting common attacks and used them to probe all exit relays over a period
of four months. We discovered numerous malicious exit relays engaging in
different attacks. To reduce the attack surface users are exposed to, we
further discuss the design and implementation of a browser extension patch
which fetches and compares suspicious X.509 certificates over independent Tor
circuits.
  Our work makes it possible to continuously monitor Tor exit relays. We are
able to detect and thwart many man-in-the-middle attacks which makes the
network safer for its users. All our code is available under a free license.


title: Blind deconvolution of density-matrix renormalization-group spectra

abstract:
  We present a numerical method for calculating piecewise smooth spectral
functions of correlated quantum systems in the thermodynamic limit from the
spectra of finite systems computed using the dynamical or correction-vector
density-matrix renormalization group method. The key idea is to consider this
problem as a blind deconvolution with an unknown kernel which causes both a
broadening and finite-size corrections of the spectrum. In practice, the method
reduces to a least-square optimization under non-linear constraints which
enforce the positivity and piecewise smoothness of spectral functions. The
method is demonstrated on the single-particle density of states of
one-dimensional paramagnetic Mott insulators represented by the half-filled
Hubbard model on an open chain. Our results confirm that the density of states
has a step-like shape but no square-root singularity at the spectrum onset.


title: A nonlinear general Neumann problem involving two critical

abstract:
  We discuss the existence of solutions of nonlinear problem involving,two
critical Sobolev exponents. we will ll out the su cient conditions to nd
solutions for the problem in presence of a nonlinear Neumann boundary data with
a critical nonlinearity. \


title: On the directional Lelong-Demailly numbers of positive currents

abstract:
  In this paper we study the existence of the directional Lelong-Demailly
numbers of positive plurisubharmonic or plurisuperharmonic currents. We prove
the independence of these numbers to the system of coordinates. Moreover these
numbers will be given by locally integrable functions.


title: Canonical structure of higher derivative theories

abstract:
  The canonical structure of theories whose Lagrangian contains higher powers
of time derivatives is often obscured by the nonlinear relationship between the
velocities and momenta. We use the Dirac formalism and define a generalized
Legendre transform to overcome some of the difficulties associated with
inverting the relation between velocities and momenta. We are then able to
define a standard single valued symplectic structure on phase space and a
compatible single valued Hamiltonian. We demonstrate the application of our
formalism in several examples.


title: A tree-growth model to optimize silviculture

abstract:
  In this paper, we present the description of a simplified model of the
dynamic of a mono-specific even-aged forest. The model studied is a tree-growth
model based on a system of two ordinary differential equations concerning the
tree basal area and the number of trees. The analytical study of this model
permits us to predict the behavior of the system solutions. We are trying to
highlight the influence of economic parameters and growth parameters on the
system solutions, in the framework of the optimization of silviculture.


title:
On the radiative and thermodynamic properties of the extragalactic far
  infrared background radiation using COBE FIRAS instrument data

abstract:
  Using the explicit form of the function to describe the average spectrum of
the extragalactic far infrared background (FIRB) radiation measured by the COBE
FIRAS instrument in the 0.15 - 2.4 THz frequency interval, the radiative and
thermodynamic properties, such as the total emissivity, total radiation power
per unit area, total energy density, number density of photons, Helmholtz free
energy density, entropy density, heat capacity at constant volume, pressure,
enthalpy density, and internal energy density are calculated. The calculated
value of the total intensity received in the 0.15 - 2.4 THz frequency interval
is 13.6 nW m^-2 sr^-1, and comprises about 19.4 % of the total intensity
expected from the energy released by stellar nucleosynthesis over cosmic
history. The radiative and thermodynamic functions of the extragalactic far
infrared background (FIRB) radiation are calculated at redshift z = 1.5.


title: Radiative and mechanical feedback into the molecular gas of NGC 253

abstract:
  Starburst galaxies are undergoing intense periods of star formation.
Understanding the heating and cooling mechanisms in these galaxies can give us
insight to the driving mechanisms that fuel the starburst. Molecular emission
lines play a crucial role in the cooling of the excited gas. With SPIRE on the
Herschel Space Observatory we have observed the rich molecular spectrum towards
the central region of NGC 253. CO transitions from J=4-3 to 13-12 are observed
and together with low-J line fluxes from ground based observations, these lines
trace the excitation of CO. By studying the CO excitation ladder and comparing
the intensities to models, we investigate whether the gas is excited by UV
radiation, X-rays, cosmic rays, or turbulent heating. Comparing the $^{12}$CO
and $^{13}$CO observations to large velocity gradient models and PDR models we
find three main ISM phases. We estimate the density, temperature,and masses of
these ISM phases. By adding $^{13}$CO, HCN, and HNC line intensities, we are
able to constrain these degeneracies and determine the heating sources. The
first ISM phase responsible for the low-J CO lines is excited by PDRs, but the
second and third phases, responsible for the mid to high-J CO transitions,
require an additional heating source. We find three possible combinations of
models that can reproduce our observed molecular emission. Although we cannot
determine which of these are preferable, we can conclude that mechanical
heating is necessary to reproduce the observed molecular emission and cosmic
ray heating is a negligible heating source. We then estimate the mass of each
ISM phase; $6\times 10^7$ M$_\odot$ for phase 1 (low-J CO lines), $3\times
10^7$ M$_\odot$ for phase 2 (mid-J CO lines), and $9\times 10^6$ M$_\odot$ for
phase 3 (high-J CO lines) for a total system mass of $1\times10^{8}$ M$_\odot$.


title:
Generating Functions with $\tau$-Invariance and Vertex Representations
  of Quantum Affine Algebras $U_{r,s}(\widehat{\mathfrak{g}})$ (I):
  Simply-laced Cases

abstract:
  We put forward the exact version of two-parameter generating functions with
$\tau$-invariance, which allows us to give a unified and inherent definition
for the Drinfeld realization of two-parameter quantum affine algebras for all
the untwisted types. As verification, we first construct their level-one vertex
representations of $U_{r,s}(\widehat{\mathfrak{g}})$ for simply-laced types,
which in turn well-detect the effectiveness of our definitions both for
$(r,s)$-generating functions and $(r,s)$-Drinfeld realization in the framework
of establishing the two-parameter vertex representation theory.


title:
Rabi model as a quantum coherent heat engine: From quantum biology to
  superconducting circuits

abstract:
  We propose a multilevel quantum heat engine with a working medium described
by a generalized Rabi model which consists of a two-level system coupled to a
single mode bosonic field. The model is constructed to be a continuum limit of
a quantum biological description of light harvesting complexes so that it can
amplify quantum coherence by a mechanism which is a quantum analog of classical
Huygen's clocks. The engine operates in quantum Otto cycle where the working
medium is coupled to classical heat baths in the isochoric processes of the
four stroke cycle; while either the coupling strength or the resonance
frequency is changed in the adiabatic stages. We found that such an engine can
produce work with an efficiency close to Carnot bound when it operates at low
temperatures and in the ultrastrong coupling regime. Interplay of quantum
coherence and quantum correlations on the engine performance is discussed in
terms of second order coherence, quantum mutual information and logarithmic
negativity of entanglement. We point out that the proposed quantum Otto engine
can be implemented experimentally with the modern circuit quantum
electrodynamic systems where flux qubits can be coupled ultrastrongly to
superconducting transmission line resonators.


title:
Linear Programming Tools for Analyzing Strategic Games of
  Independence-Friendly Logic and Applications

abstract:
  In recent work, semantic games of independence-friendly logic were studied in
strategic form in terms of (mixed strategy) Nash equilibria. The class of
strategic games of independence-friendly logic is contained in the class of
win-loss, zero-sum two-player games. In this note we draw on the theory of
linear programming to develop tools to analyze the value of such games. We give
two applications of these tools to independence-friendly logic under the
so-called equilibrium semantics.


title: Large subgraphs without short cycles

abstract:
  We study two extremal problems about subgraphs excluding a family $\F$ of
graphs. i) Among all graphs with $m$ edges, what is the smallest size $f(m,\F)$
of a largest $\F$--free subgraph? ii) Among all graphs with minimum degree
$\delta$ and maximum degree $\Delta$, what is the smallest minimum degree
$h(\delta,\Delta,\F)$ of a spanning $\F$--free subgraph with largest minimum
degree? These questions are easy to answer for families not containing any
bipartite graph. We study the case where $\F$ is composed of all even cycles of
length at most $2r$, $r\geq 2$. In this case, we give bounds on $f(m,\F)$ and
$h(\delta,\Delta,\F)$ that are essentially asymptotically tight up to a
logarithmic factor. In particular for every graph $G$, we show the existence of
subgraphs with arbitrarily high girth, and with either many edges or large
minimum degree. These subgraphs are created using probabilistic embeddings of a
graph into extremal graphs.


title:
Variance reduction for steady-state simulation and sensitivity analysis
  of stochastic chemical systems

abstract:
  We address the problem of estimating steady-state quantities associated to
systems of stochastic chemical kinetics. In most cases of interest these
systems are analytically intractable, and one has to resort to computational
methods to estimate stationary values of cost functions. In this work we
consider a previously introduced variance reduction method and present an
algorithm for its application in the context of stochastic chemical kinetics.
Using two numerical examples, we test the efficiency of the method for the
calculation of steady-state parametric sensitivities and evaluate its
performance in comparison to other estimation methods.


title:
Determining polarizability tensors for an arbitrary small
  electromagnetic scatterer

abstract:
  In this paper, we present a method to retrieve tensor polarizabilities of
general bi-anisotropic particles from their far-field responses to plane-wave
illuminations. The necessary number of probing excitations and the directions
where the scattered fields need to be calculated or measured have been found.
When implemented numerically, the method does not require any spherical
harmonic expansion nor direct calculation of dipole moments, but only
calculations of co- and cross-polarized scattering cross sections for a number
of plane-wave excitations. With this simple approach, the polarizabilities can
be found also from experimentally measured cross sections. The method is
exemplified considering two bi-anisotropic particles, a reciprocal omega
particle and a non-reciprocal particle containing a ferrite inclusion coupled
to metal strips.


title:
A domination algorithm for $\{0,1\}$-instances of the travelling
  salesman problem

abstract:
  We present an approximation algorithm for $\{0,1\}$-instances of the
travelling salesman problem which performs well with respect to combinatorial
dominance. More precisely, we give a polynomial-time algorithm which has
domination ratio $1-n^{-1/29}$. In other words, given a
$\{0,1\}$-edge-weighting of the complete graph $K_n$ on $n$ vertices, our
algorithm outputs a Hamilton cycle $H^*$ of $K_n$ with the following property:
the proportion of Hamilton cycles of $K_n$ whose weight is smaller than that of
$H^*$ is at most $n^{-1/29}$. Our analysis is based on a martingale approach.
Previously, the best result in this direction was a polynomial-time algorithm
with domination ratio $1/2-o(1)$ for arbitrary edge-weights. We also prove a
hardness result showing that, if the Exponential Time Hypothesis holds, there
exists a constant $C$ such that $n^{-1/29}$ cannot be replaced by $\exp(-(\log
n)^C)$ in the result above.


title:
The existential fragment of S1S over element and successor is the
  co-Buchi languages

abstract:
  Buchi's theorem, in establishing the equivalence between languages definable
in S1S over element and < and the omega-regular languages also demonstrated
that S1S over element and < is no more expressive than its existential
fragment. It is also easy to see that S1S over element and < is equi-expressive
with S1S over element and successor. However, it is not immediately obvious
whether it is possible to adapt Buchi's argument to establish equivalence
between expressivity in S1S over element and successor and its existential
fragment. In this paper we show that it is not: the existential fragment of S1S
over element and successor is strictly less expressive, and is in fact
equivalent to the co-Buchi languages.


title: Treating Time Travel Quantum Mechanically

abstract:
  The fact that closed timelike curves (CTCs) are permitted by general
relativity raises the question as to how quantum systems behave when time
travel to the past occurs. Research into answering this question by utilising
the quantum circuit formalism has given rise to two theories: Deutschian-CTCs
(D-CTCs) and "postselected" CTCs (P-CTCs). In this paper the quantum circuit
approach is thoroughly reviewed, and the strengths and shortcomings of D-CTCs
and P-CTCs are presented in view of their non-linearity and time travel
paradoxes. In particular, the "equivalent circuit model"---which aims to make
equivalent predictions to D-CTCs, while avoiding some of the difficulties of
the original theory---is shown to contain errors. The discussion of D-CTCs and
P-CTCs is used to motivate an analysis of the features one might require of a
theory of quantum time travel, following which two overlapping classes of new
theories are identified. One such theory, the theory of "transition
probability" CTCs (T-CTCs), is fully developed. The theory of T-CTCs is shown
not to have certain undesirable features---such as time travel paradoxes, the
ability to distinguish non-orthogonal states with certainty, and the ability to
clone or delete arbitrary pure states---that are present with D-CTCs and
P-CTCs. The problems with non-linear extensions to quantum mechanics are
discussed in relation to the interpretation of these theories, and the physical
motivations of all three theories are discussed and compared.


title:
An explicit formula for computing Bernoulli numbers of the second kind
  in terms of Stirling numbers of the first kind

abstract:
  In the paper, the author finds an explicit formula for computing Bernoulli
numbers of the second kind in terms of Stirling numbers of the first kind.


title: Performance Analysis of a Network of Event-based Systems

abstract:
  We consider a scenario where multiple event-based systems use a wireless
network to communicate with their respective controllers. These systems use a
contention resolution mechanism (CRM) to arbitrate access to the network. We
present a Markov model for the network interactions between the event-based
systems. Using this model, we obtain an analytical expression for the
reliability, or the probability of successfully transmitting a packet, in this
network. There are two important aspects to our model. Firstly, our model
captures the joint interactions of the event-triggering policy and the CRM.
This is required because event-triggering policies typically adapt to the CRM
outcome. Secondly, the model is obtained by decoupling interactions between the
different systems in the network, drawing inspiration from Bianchi's analysis
of IEEE 802.11. This is required because the network interactions introduce a
correlation between the system variables. We present Monte-Carlo simulations
that validate our model under various network configurations, and verify our
performance analysis as well.


title:
Low-Complexity Robust Data-Adaptive Dimensionality Reduction Based on
  Joint Iterative Optimization of Parameters

abstract:
  This paper presents a low-complexity robust data-dependent dimensionality
reduction based on a modified joint iterative optimization (MJIO) algorithm for
reduced-rank beamforming and steering vector estimation. The proposed robust
optimization procedure jointly adjusts the parameters of a rank-reduction
matrix and an adaptive beamformer. The optimized rank-reduction matrix projects
the received signal vector onto a subspace with lower dimension. The
beamformer/steering vector optimization is then performed in a
reduced-dimension subspace. We devise efficient stochastic gradient and
recursive least-squares algorithms for implementing the proposed robust MJIO
design. The proposed robust MJIO beamforming algorithms result in a faster
convergence speed and an improved performance. Simulation results show that the
proposed MJIO algorithms outperform some existing full-rank and reduced-rank
algorithms with a comparable complexity.


title: Multi-wavelength variability properties of Fermi blazar S5 0716+714

abstract:
  S5 0716+714 is a typical BL Lacertae object. In this paper we present the
analysis and results of long term simultaneous observations in the radio,
near-infrared, optical, X-ray and $\gamma$-ray bands, together with our own
photometric observations for this source. The light curves show that the
variability amplitudes in $\gamma$-ray and optical bands are larger than those
in the hard X-ray and radio bands and that the spectral energy distribution
(SED) peaks move to shorter wavelengths when the source becomes brighter, which
are similar to other blazars, i.e., more variable at wavelengths shorter than
the SED peak frequencies. Analysis shows that the characteristic variability
timescales in the 14.5 GHz, the optical, the X-ray, and the $\gamma$-ray bands
are comparable to each other. The variations of the hard X-ray and 14.5 GHz
emissions are correlated with zero-lag, so are the V band and $\gamma$-ray
variations, which are consistent with the leptonic models. Coincidences of
$\gamma$-ray and optical flares with a dramatic change of the optical
polarization are detected. Hadronic models do not have the same nature
explanation for these observations as the leptonic models. A strong optical
flare correlating a $\gamma$-ray flare whose peak flux is lower than the
average flux is detected. Leptonic model can explain this variability
phenomenon through simultaneous SED modeling. Different leptonic models are
distinguished by average SED modeling. The synchrotron plus synchrotron
self-Compton (SSC) model is ruled out due to the extreme input parameters.
Scattering of external seed photons, such as the hot dust or broad line region
emission, and the SSC process are probably both needed to explain the
$\gamma$-ray emission of S5 0716+714.


title:
Consciousness and Learning based on DNA Recombination and Memristor
  Quality of Microtubules

abstract:
  This paper is a completion of an earlier model proposed by us. In the model
different memories are attached at cell surface determinants which are the
result of DNA recombination. Our earlier experiments strongly suggest that DNA
recombination actually takes place during a short period of early development
in the brain in a limited number of neurons. In the present paper a model is
presented in which switchboard neurons play a key role in the storage and
retrieving of memory. And as a consequence, they play a major role in the
process of learning and form the basic material for consciousness. In the
original model there was insufficient explanation for the realization of the
internal connection of one cell surface determinant to the other. We realized
that tubulin should play a role in these intracellular connections. The tubulin
molecules can form a connective wire because of a change of shape of the
individual tubulin dimers. This way the fast switch is realized by the switch
of the tubulin dimer configuration. Because the cell should remember which
switch was activated and which one was not or less activated, we postulate the
memristor quality of microtubules.


title:
Extreme values and the level-crossing problem. An application to the
  Feller process

abstract:
  We review the question of the extreme values attained by a random process. We
relate it to level crossings either to one boundary (first-passage problems)
and two boundaries (escape problems). The extremes studied are the maximum, the
minimum, the maximum absolute value and the range or span. We specialize in
diffusion processes and present detailed results for the Wiener and Feller
processes.


title:
The impact of the ghost-gluon vertex on the ghost Schwinger-Dyson
  equations

abstract:
  We derive an approximate dynamical equation for the form-factor of the
ghost-gluon vertex that contributes to the Schwinger-Dyson equation of the
ghost dressing function in the Landau gauge. In particular, we consider the
"one-loop dressed" approximation of the corresponding equation governing the
evolution of the ghost-gluon vertex, using fully dressed propagators and
tree-level vertices in the relevant diagrams. Within this approximation, we
then compute the aforementioned form factor for two special kinematic
configurations, namely the soft gluon limit, in which the momentum carried by
the gluon leg is zero, and the soft ghost limit, where the momentum of the
anti-ghost leg vanishes. The results obtained display a considerable departure
from the tree-level value, and are in rather good agreement with available
lattice data. We next solve numerically the coupled system formed by the
equation of the ghost dressing function and that of the the vertex form factor,
in the soft ghost limit. Our results demonstrate clearly that the
nonperturbative contribution from the ghost-gluon vertex accounts for the
missing strength in the kernel of the ghost equation, and allows for an
impressive coincidence with the lattice results, without the need to
artificially enhance the coupling constant of the theory.


title: Cosmic Ray Acceleration in Magnetic Reconnection Sites

abstract:
  Cosmic Ray (CR) acceleration still challenges the researchers. Fast particles
may be accelerated in astrophysical environments by a variety of processes.
Acceleration in magnetic reconnection sites in particular, has lately attracted
the attention of researchers not only for its potential importance in the solar
system context, but also in other astrophysical environments, like compact
stellar sources, AGNs and GRBs, and even in diffusive media like the ISM and
the IGM, especially when the environment is magnetically dominated. In this
talk we review this process and also present three-dimensional collisional MHD
simulations with the injection of thousands of test particles showing from the
evolution of their energy spectrum that they can be efficiently accelerated by
reconnection through a first-order Fermi process within large scale magnetic
current sheets (especially when local turbulence is present which makes
reconnection fast and the acceleration layer thicker).


title: Info-computational constructivism in modelling of life as cognition

abstract:
  This paper addresses the open question formulated as: Which levels of
abstraction are appropriate in the synthetic modelling of life and cognition?
within the framework of info-computational constructivism, treating natural
phenomena as computational processes on informational structures. At present we
lack the common understanding of the processes of life and cognition in living
organisms with the details of co-construction of informational structures and
computational processes in embodied, embedded cognizing agents, both living and
artifactual ones. Starting with the definition of an agent as an entity capable
of acting on its own behalf, as an actor in Hewitt Actor model of computation,
even so simple systems as molecules can be modelled as actors exchanging
messages (information). We adopt Kauffmans view of a living agent as something
that can reproduce and undergoes at least one thermodynamic work cycle. This
definition of living agents leads to the Maturana and Varelas identification of
life with cognition. Within the info-computational constructive approach to
living beings as cognizing agents, from the simplest to the most complex living
systems, mechanisms of cognition can be studied in order to construct synthetic
model classes of artifactual cognizing agents on different levels of
organization.


title: Diffractive Dissociation into Three-Pion Final States at COMPASS

abstract:
  In order to study diffractive dissociation reactions, COMPASS has taken data
with a 190 GeV/$c$ pion beam impinging on a liquid hydrogen target in 2008 and
2009. At squared four-momentum transfers to the target t' between 0.1
GeV$^2/c^2$ and 1.0 GeV$^2/c^2$ the number of events with three pions in the
final state is about an order of magnitude larger than that acquired by any
previous experiment. In COMPASS, the three-pion final state can be studied in
the two channels $\pi^-\pi^-\pi^+$ and $\pi^-\pi^0\pi^0$. The large data sample
in particular for the $\pi^-\pi^-\pi^+$ channel allows to find even small
signals at the sub-percent level. The progress of the partial-wave analysis
will be shown. Compared to previous COMPASS results, the analysis is now
performed in bins of t', and the set of partial waves has been extended now
including waves up to spin 6. The information from the t' dependence of the
individual partial waves is very helpful in separating resonant and
non-resonant contributions. As a consistency check results from the
$\pi^-\pi^-\pi^+$ channel will be compared to the $\pi^-\pi^0\pi^0$ channel.


title: Iterative pre-distortion of the non-linear satellite channel

abstract:
  Digital Video Broadcasting - Satellite - Second Generation (DVB-S2) is the
current European standard for satellite broadcast and broadband communications.
It relies on high order modulations up to 32-amplitude/phase-shift-keying
(APSK) in order to increase the system spectral efficiency. Unfortunately, as
the modulation order increases, the receiver becomes more sensitive to physical
layer impairments, and notably to the distortions induced by the power
amplifier and the channelizing filters aboard the satellite. Pre-distortion of
the non-linear satellite channel has been studied for many years. However, the
performance of existing pre-distortion algorithms generally becomes poor when
high-order modulations are used on a non-linear channel with a long memory. In
this paper, we investigate a new iterative method that pre-distorts blocks of
transmitted symbols so as to minimize the Euclidian distance between the
transmitted and received symbols. We also propose approximations to relax the
pre-distorter complexity while keeping its performance acceptable.


title:
Free-carrier driven spatio-temporal dynamics in amplifying silicon
  waveguides

abstract:
  We theoretically investigate the free-carrier induced spatio-temporal
dynamics of continuous waves in silicon waveguides embedded in an amplifying
medium. Optical propagation is governed by a cubic Ginzburg-Landau equation
coupled with an ordinary differential equation accounting for the free-carrier
dynamics. We find that, owing to free-carrier dispersion, countinuous waves are
modulationally unstable in both anomalous and normal dispersion regimes and
chaotically generate unstable accelerating pulses.


title: Regularity for the fractional Gelfand problem up to dimension 7

abstract:
  We study the problem $(-\Delta)^su=\lambda e^u$ in a bounded domain
$\Omega\subset\mathbb R^n$, where $\lambda$ is a positive parameter. More
precisely, we study the regularity of the extremal solution to this problem.
  Our main result yields the boundedness of the extremal solution in dimensions
$n\leq7$ for all $s\in(0,1)$ whenever $\Omega$ is, for every $i=1,...,n$,
convex in the $x_i$-direction and symmetric with respect to $\{x_i=0\}$. The
same holds if $n=8$ and $s\gtrsim0'28206...$, or if $n=9$ and
$s\gtrsim0'63237...$. These results are new even in the unit ball $\Omega=B_1$.


title:
Fast dynamics and spectral properties of a multilongitudinal-mode
  semiconductor laser: evolution of an ensemble of driven, globally coupled
  nonlinear modes

abstract:
  We analyze the fast transient dynamics of a multi-longitudinal mode
semiconductor laser on the basis of a model with intensity coupling. The
dynamics, coupled to the constraints of the system and the below-threshold
initial conditions, imposes a faster growth of the side modes in the initial
stages of the transient, thereby leading the laser through a sequence of states
where the modal intensity distribution dramatically differs from the asymptotic
one. A detailed analysis of the below-threshold, deterministic dynamical
evolution allows us to explain the modal dynamics in the strongly coupled
regime where the total intensity peak and relaxation oscillations take place,
thus providing an explanation for the modal dynamics observed in the slow,
hidden evolution towards the asymptotic state (cf. Phys. Rev. A 85, 043823
(2012)). The dynamics of this system can be interpreted as the transient
response of a driven, globally coupled ensemble of nonlinear modes evolving
towards an equilibrium state. Since the qualitative dynamics do not depend on
the details of the interaction but only on the structure of the coupling, our
results hold for a whole class of globally, bilinearly coupled oscillators.


title: The LAUE project and its main results

abstract:
  We will describe the LAUE project, supported by the Italian Space Agency,
whose aim is to demonstrate the capability to build a focusing optics in the
hard X-/soft gamma-ray domain (80--600 keV). To show the lens feasibility, the
assembling of a Laue lens petal prototype with 20 m focal length is ongoing.
Indeed, a feasibility study, within the LAUE project, has demonstrated that a
Laue lens made of petals is feasible. Our goal is a lens in the 80-600 keV
energy band. In addition to a detailed description of the new LARIX facility,
in which the lens is being assembled, we will report the results of the project
obtained so far.


title:
Conjectures on Bridgeland stability for Fukaya categories of Calabi-Yau
  manifolds, special Lagrangians, and Lagrangian mean curvature flow

abstract:
  Let $M$ be a Calabi-Yau $m$-fold, and consider compact, graded Lagrangians
$L$ in $M$. Thomas and Yau math.DG/0104196, math.DG/0104197 conjectured that
there should be a notion of "stability" for such $L$, and that if $L$ is stable
then Lagrangian mean curvature flow $\{L^t:t\in[0,\infty)\}$ with $L^0=L$
should exist for all time, and $L^\infty=\lim_{t\to\infty}L^t$ should be the
unique special Lagrangian in the Hamiltonian isotopy class of $L$. This paper
is an attempt to update the Thomas-Yau conjectures, and discuss related issues.
  It is a folklore conjecture that there exists a Bridgeland stability
condition $(Z,\mathcal P)$ on the derived Fukaya category $D^b\mathcal F(M)$ of
$M$, such that an isomorphism class in $D^b\mathcal F(M)$ is $(Z,\mathcal
P)$-semistable if (and possibly only if) it contains a special Lagrangian,
which must then be unique.
  We conjecture that if $(L,E,b)$ is an object in an enlarged version of
$D^b\mathcal F(M)$, where $L$ is a compact, graded Lagrangian in $M$ (possibly
immersed, or with "stable singularities"), $E\to M$ a rank one local system,
and $b$ a bounding cochain for $(L,E)$ in Lagrangian Floer cohomology, then
there is a unique family $\{(L^t,E^t,b^t):t\in[0,\infty)\}$ such that
$(L^0,E^0,b^0)=(L,E,b)$, and $(L^t,E^t,b^t)\cong(L,E,b)$ in $D^b\mathcal F(M)$
for all $t$, and $\{L^t:t\in[0,\infty)\}$ satisfies Lagrangian MCF with
surgeries at singular times $T_1,T_2,\dots,$ and in graded Lagrangian integral
currents we have $\lim_{t\to\infty}L^t=L_1+\cdots+L_n$, where $L_j$ is a
special Lagrangian integral current of phase $e^{i\pi\phi_j}$ for
$\phi_1>\cdots>\phi_n$, and $(L_1,\phi_1),\ldots,(L_n,\phi_n)$ correspond to
the decomposition of $(L,E,b)$ into $(Z,\mathcal P)$-semistable objects.
  We also give detailed conjectures on the nature of the singularities of
Lagrangian MCF that occur at the finite singular times $T_1,T_2,\ldots.$


title: MRRR-based Eigensolvers for Multi-core Processors and Supercomputers

abstract:
  The real symmetric tridiagonal eigenproblem is of outstanding importance in
numerical computations; it arises frequently as part of eigensolvers for
standard and generalized dense Hermitian eigenproblems that are based on a
reduction to tridiagonal form. For its solution, the algorithm of Multiple
Relatively Robust Representations (MRRR or MR3 in short) - introduced in the
late 1990s - is among the fastest methods. To compute k eigenpairs of a real
n-by-n tridiagonal T, MRRR only requires O(kn) arithmetic operations; in
contrast, all the other practical methods require O(k^2 n) or O(n^3) operations
in the worst case. This thesis centers around the performance and accuracy of
MRRR.


title:
Electronic transport and device prospects of monolayer molybdenum
  disulphide grown by chemical vapour deposition

abstract:
  Layered transition metal dichalcogenides display a wide range of attractive
physical and chemical properties and are potentially important for various
device applications. Here we report the electronic transport and device
properties of monolayer molybdenum disulphide (MoS2) grown by chemical vapour
deposition (CVD). We show that these devices have the potential to suppress
short channel effects and have high critical breakdown electric field. However,
our study reveals that the electronic properties of these devices are at
present, severely limited by the presence of a significant amount of band tail
trapping states. Through capacitance and ac conductance measurements, we
systematically quantify the density-of-states and response time of these
states. Due to the large amount of trapped charges, the measured effective
mobility also leads to a large underestimation of the true band mobility and
the potential of the material. Continual engineering efforts on improving the
sample quality are needed for its potential applications.


title:
Packing circles within circular containers: a new heuristic algorithm
  for the balance constraints case

abstract:
  In this work we propose a heuristic algorithm for the layout optimization for
disks installed in a rotating circular container. This is a unequal circle
packing problem with additional balance constraints. It proved to be an NP-hard
problem, which justifies heuristics methods for its resolution in larger
instances. The main feature of our heuristic is based on the selection of the
next circle to be placed inside the container according to the position of the
system's center of mass. Our approach has been tested on a series of instances
up to 55 circles and compared with the literature. Computational results show
good performance in terms of solution quality and computational time for the
proposed algorithm.


title: Constructing Fewer Open Cells by GCD Computation in CAD Projection

abstract:
  A new projection operator based on cylindrical algebraic decomposition (CAD)
is proposed. The new operator computes the intersection of projection factor
sets produced by different CAD projection orders. In other words, it computes
the gcd of projection polynomials in the same variables produced by different
CAD projection orders. We prove that the new operator still guarantees
obtaining at least one sample point from every connected component of the
highest dimension, and therefore, can be used for testing semi-definiteness of
polynomials. Although the complexity of the new method is still doubly
exponential, in many cases, the new operator does produce smaller projection
factor sets and fewer open cells. Some examples of testing semi-definiteness of
polynomials, which are difficult to be solved by existing tools, have been
worked out efficiently by our program based on the new method.


title: Bases normales autoduales et groupes unitaires en caract\'eristique 2

abstract:
  Let k be a field of characteristic 2 and let L/k be a finite Galois extension
with Galois group G. We show the equivalence of the following two properties:
  (*) The group G is generated by elements of order 2 and by elements of odd
order.
  (**) There exists an element x of L such that Tr(x) = 1 and T(x.g(x)) = 0 for
every non trivial element g of G.


title: An operator based approach to irregular frames of translates

abstract:
  We consider translates of functions in $L^2(\RRd)$ along an irregular set of
points. Introducing a notion of pseudo-Gramian function for the irregular case,
we obtain conditions for a family of irregular translates to be a Bessel
sequence or Riesz sequence.
  We find a representation of the canonical dual of a frame sequence $\{\phi(
\cdot - \lambda_k)\}_{k\in \ZZ}$ - where $\phi$ is a bandlimited function - in
terms of its Fourier transform.


title: The life cycle of Drosophila orphan genes

abstract:
  Orphans are genes restricted to a single phylogenetic lineage and emerge at
high rates. While this predicts an accumulation of genes, the gene number has
remained remarkably constant through evolution. This paradox has not yet been
resolved. Because orphan genes have been mainly analyzed over long evolutionary
time scales, orphan loss has remained unexplored. Here we study the patterns of
orphan turnover among close relatives in the Drosophila obscura group. We show
that orphans are not only emerging at a high rate, but that they are also
rapidly lost. Interestingly, recently emerged orphans are more likely to be
lost than older ones. Furthermore, highly expressed orphans with a strong
male-bias are more likely to be retained. Since both lost and retained orphans
show similar evolutionary signatures of functional conservation, we propose
that orphan loss is not driven by high rates of sequence evolution, but
reflects lineage specific functional requirements.


title: Crystals and liquid crystals confined to curved geometries

abstract:
  This review introduces the elasticity theory of two-dimensional crystals and
nematic liquid crystals on curved surfaces, the energetics of topological
defects (disclinations, dislocations and pleats) in these ordered phases, and
the interaction of defects with the underlying curvature. This chapter
concludes with two cases of three-dimensional nematic phases confined to spaces
with curved boundaries, namely a torus and a spherical shell.


title: Counting rational points near planar curves

abstract:
  We find an asymptotic formula for the number of rational points near planar
curves. More precisely, if $f:\mathbb{R}\rightarrow\mathbb{R}$ is a
sufficiently smooth function defined on the interval $[\eta,\xi]$, then the
number of rational points with denominator no larger than $Q$ that lie within a
$\delta$-neighborhood of the graph of $f$ is shown to be asymptotically
equivalent to $(\xi-\eta)\delta Q^2$.


title:
Interface size dependence of the Josephson critical behaviour in
  pyrolytic graphite

abstract:
  We have studied the transport properties of TEM lamellae obtained from a
pyrolytic graphite sample with electrical contacts at the edges of the embedded
interfaces. The temperature dependence of the resistance as well as the
current-voltage characteristic curves are compatible with the existence of
Josephson coupled superconducting regions. The transition temperature at which
the Josephson behavior sets in, decreases with the interface width and vanishes
for width below 200~nm. This unexpected behavior is apparently due to the
influence of weak localization effects on the superconducting critical
temperature.


title: $W$-algebras and higher analogs of the Kniznik-Zamolodchikov equations

abstract:
  The key role in the derivation of the Knizhnik-Zamolodchikov equations in the
$WZW$-theory is played by the energy-momentum tensor, that is constructed from
a central Casimir element of the second order in a universal enveloping algebra
of a corresponding Lie algebra. In the paper a possibility of construction of
analogs of Knizhnik-Zamolodchikov equations using higher order central elements
is investigated. The Gelfand elements of the third order for a simple Lie
algebra of series $A$ and Capelli elements of the fourth order for the a simple
Lie algebra of series $B$, $D$ are considered. In the first case the
construction is not possible a the second case the desired equation is derived.


title: Cavity cooling of an atomic array

abstract:
  While cavity cooling of a single trapped emitter was demonstrated, cooling of
many particles in an array of harmonic traps needs investigation and poses a
question of scalability. This work investigates the cooling of a one
dimensional atomic array to the ground state of motion via the interaction with
the single mode field of a high-finesse cavity. The key factor ensuring the
cooling is found to be the mechanical inhomogeneity of the traps. Furthermore
it is shown that the pumped cavity mode does not only mediate the cooling but
also provides the necessary inhomogeneity if its periodicity differs from the
one of the array. This configuration results in the ground state cooling of
several tens of atoms within a few milliseconds, a timescale compatible with
current experimental conditions. Moreover, the cooling rate scaling with the
atom number reveals a drastic change of the dynamics with the size of the
array: atoms are either cooled independently, or via collective modes. In the
latter case the cavity mediated atom interaction destructively slows down the
cooling as well as increases the mean occupation number, quadratically with the
atom number. Finally, an order of magnitude speed up of the cooling is
predicted as an outcome the optimization scheme based on the adjustment of the
array versus the cavity mode periodicity.


title:
Submillimeter Array and Very Large Array Observations in the
  Hypercompact HII region G35.58-0.03

abstract:
  The formation of hypercompact (HC) HII regions is an important stage in
massive star formation. Spectral line and continuum observations can explore
its dynamic conditions. We present high angular resolution observations carried
out with the Submillimeter Array (SMA) and the Very Large Array (VLA) toward
the HC HII region G35.58-0.03. With the 1.3 mm SMA and 1.3 cm VLA, we detected
a total of about 25 transitions of 8 different species and their isotopologues
(CO, CH$_3$CN, SO$_2$, CH$_3$CCH, OCS, CS, H, and NH$_{3}$). G35.58-0.03
consists of an HC HII core with electron temperature $T_e^*\geqq5500$ K,
emission measure EM $\approx 1.9\times10^{9}$ pc cm$^{-6}$, local volume
electron density $n_e=3.3\times10^{5}$ cm$^{-3}$, and a same width of radio
recombination line FWHM $\approx$ 43.2 km s$^{-1}$ for both H30$\alpha$ and
H38$\beta$ at its intrinsic core size $\sim$3714 AU. The H30$\alpha$ line shows
evidence of an ionized outflow driving a molecular outflow. Based on the
derived Lyman continuum flux, there should be an early-type star equivalent to
O6.5 located inside the HII region. From the continuum spectral energy
distribution from 3.6 cm, 2.0 cm, 1.3 cm, 1.3 mm and 0.85 mm to 0.45 mm, we
distinguished the free-free emission (25% $\sim$ 55%) from the warm dust
component (75% $\sim$ 45%) at 1.3 mm. The molecular envelope shows evidence of
infall and outflow with an infall rate 0.05 M$_{ \odot}$ yr$^{-1}$ and a mass
loss rate $5.2\times10^{-3}$ ${\rm M_{ \odot} yr^{-1}}$. The derived momentum
($\sim0.05$ M$_{\odot}$ km s$^{-1}$) is consistent between the infalling and
outflowing gas per year. It is suggested that the infall is predominant and the
envelope mass of dense core is increasing rapidly, but the accretion in the
inner part might already be halted.


title:
Frequency response of an atomic resonance driven by weak
  free-electron-laser fluctuating pulses

abstract:
  Motivated by recent experiments pertaining to the interaction of weak
SASE-FEL pulses with atoms and molecules, we investigate the conditions under
which such interactions can be described in the framework of a simple
phase-diffusion model with decorrelated atom-field dynamics. The nature of the
fluctuations that are inevitably present in SASE-FEL pulses is shown to play a
pivotal role in the success of the decorrelation. Our analysis is performed in
connection with specific recent experimental results from FLASH in the soft
X-ray regime.


title:
Strict inequality of Robin eigenvalues for elliptic differential
  operators on Lipschitz domains

abstract:
  On a bounded Lipschitz domain we consider two selfadjoint operator
realizations of the same second order elliptic differential expression subject
to Robin boundary conditions, where the coefficients in the boundary conditions
are functions. We prove that inequality between these functions on the boundary
implies strict inequality between the eigenvalues of the two operators,
provided that the inequality of the functions in the boundary conditions is
strict on an arbitrarily small nonempty, open set.


title:
On the Cartesian Skeleton and the Factorization of the Strong Product of
  Digraphs

abstract:
  The three standard products (the Cartesian, the direct and the strong
product) of undirected graphs have been wellinvestigated, unique prime factor
decomposition (PFD) are known and polynomial time algorithms have been
established for determining the prime factors.
  For directed graphs, unique PFD results with respect to the standard products
are known. However, there is still a lack of algorithms, that computes the PFD
of directed graphs with respect to the direct and the strong product in
general. In this contribution, we focus on the algorithmic aspects for
determining the PFD of directed graphs with respect to the strong product.
Essential for computing the prime factors is the construction of a so-called
Cartesian skeleton. This article introduces the notion of the Cartesian
skeleton of directed graphs as a generalization of the Cartesian skeleton of
undirected graphs. We provide new, fast and transparent algorithms for its
construction. Moreover, we present a first polynomial time algorithm for
determining the PFD with respect to the strong product of arbitrary connected
digraphs.


title: Infinite and finite dimensional Hilbert tensors

abstract:
  For an $m$-order $n-$dimensional Hilbert tensor (hypermatrix)
$\mathcal{H}_n=(\mathcal{H}_{i_1i_2\cdots i_m})$, $$\mathcal{H}_{i_1i_2\cdots
i_m}=\frac1{i_1+i_2+\cdots+i_m-m+1},\ i_1,\cdots, i_m=1,2,\cdots,n$$ its
spectral radius is not larger than $n^{m-1}\sin\frac{\pi}{n}$, and an upper
bound of its $E$-spectral radius is $n^{\frac{m}2}\sin\frac{\pi}{n}$. Moreover,
its spectral radius is strictly increasing and its $E$-spectral radius is
nondecreasing with respect to the dimension $n$. When the order is even, both
infinite and finite dimensional Hilbert tensors are positive definite. We also
show that the $m$-order infinite dimensional Hilbert tensor (hypermatrix)
$\mathcal{H}_\infty=(\mathcal{H}_{i_1i_2\cdots i_m})$ defines a bounded and
positively $(m-1)$-homogeneous operator from $l^1$ into $l^p$ ($1<p<\infty$),
and the norm of corresponding positively homogeneous operator is smaller than
or equal to $\frac{\pi}{\sqrt6}$.


title: Exact scattering matrix of graphs in magnetic field and quantum noise

abstract:
  We consider arbitrary quantum wire networks modelled by finite, noncompact,
connected quantum graphs in the presence of an external magnetic field.
  We find a general formula for the total scattering matrix of the network in
terms of its local scattering properties and its metric structure. This is
applied to a quantum ring with $N$ external edges. Connecting the external
edges of the ring to heat reservoirs, we study the quantum transport on the
graph in ambient magnetic field. We consider two types of dynamics on the ring:
the free Schr\"odinger and the free massless Dirac equations. For each case, a
detailed study of the thermal noise is performed analytically.
  Interestingly enough, in presence of a magnetic field, the standard linear
Johnson-Nyquist law for the low temperature behaviour of the thermal noise
becomes nonlinear. The precise regime of validity of this effect is discussed
and a typical signature of the underlying dynamics is observed.


title: On the equations of motion of dislocations in quasicrystals

abstract:
  In this work we investigate the theory of dynamics of dislocations in
quasicrystals. We consider three models: the elastodynamic model of wave type,
the elasto-hydrodynamic model, and the elastodynamic model of wave-telegraph
type. Similarities and differences between the three models are pointed out and
discussed. Using the framework of linear incompatible elastodynamic theory, the
equations of motion of dislocations are deduced for these three models.
Especially, the equations of motion for the phonon and phason elastic
distortion tensors and elastic velocity vectors are derived, where the source
fields are given in terms of the phonon and phason dislocation density and
dislocation current tensors in analogy to the classical theory of
elastodynamics of dislocations. The equations of motion for the displacement
fields are also obtained.


title:
Local and Parallel Finite Element Algorithm Based On Multilevel
  Discretization for Eigenvalue Problem

abstract:
  A local and parallel algorithm based on the multilevel discretization is
proposed in this paper to solve the eigenvalue problem by the finite element
method. With this new scheme, solving the eigenvalue problem in the finest grid
is transferred to solutions of the eigenvalue problems on the coarsest mesh and
a series of solutions of boundary value problems by using the local and
parallel algorithm. The computational work in each processor can reach the
optimal order. Therefore, this type of multilevel local and parallel method
improves the overall efficiency of solving the eigenvalue problem. Some
numerical experiments are presented to validate the efficiency of the new
method.


title: Variable Density Turbulence Tunnel Facility

abstract:
  The Variable Density Turbulence Tunnel (VDTT) at the Max Planck Institute for
Dynamics and Self-Organization in G\"ottingen, Germany produces very high
turbulence levels at moderate flow velocities, low power consumption and
adjustable kinematic viscosity between $10^{-4} m^2/s$ and $10^{-7} m^2/s$. The
Reynolds number can be varied by changing the pressure or flow rate of the gas
or by using different non-flammable gases including air. The highest kinematic
viscosities, and hence lowest Reynolds numbers, are reached with air or
nitrogen at 0.1 bar. To reach the highest Reynolds numbers the tunnel is
pressurized to 15 bar with the dense gas sulfur hexafluoride (SF$_6$).
  Turbulence is generated at the upstream ends of two measurement sections with
grids, and the evolution of this turbulence is observed as it moves down the
length of the sections. We describe the instrumentation presently in operation,
which consists of the tunnel itself, classical grid turbulence generators, and
state-of-the-art nano-fabricated hot-wire anemometers provided by Princeton
University [Vallikivi et al. (2011) Exp. Fluids 51, 1521]. We report
measurements of the characteristic scales of the flow and of turbulent spectra
up to Taylor Reynolds number $R_\lambda \approx 1600$, higher than any other
grid-turbulence experiment. We also describe instrumentation under development,
which includes an active grid and a Lagrangian particle tracking system that
moves down the length of the tunnel with the mean flow. In this configuration,
the properties of the turbulence are adjustable and its structure is resolvable
up to $R_\lambda \approx 8000$.


title:
Computational Analysis of a Spiral Thermoelectric Nanoantenna for Solar
  Energy Harvesting Applications

abstract:
  Thermo-electrical nanoantennas have been proposed as an alternative option
for conversion solar energy harvesting applications. In this work, the response
of a spiral broadband antenna has been obtained from numerical and theoretical
simulations perspectives. The results show that this device exhibits a
responsivity of 20mV/W under 117W/cm2, for a single-frequency radiation. We
discuss strategies for enhanced efficiency.


title:
Compact Deterministic Self-Stabilizing Leader Election: The Exponential
  Advantage of Being Talkative

abstract:
  This paper focuses on compact deterministic self-stabilizing solutions for
the leader election problem. When the protocol is required to be \emph{silent}
(i.e., when communication content remains fixed from some point in time during
any execution), there exists a lower bound of Omega(\log n) bits of memory per
node participating to the leader election (where n denotes the number of nodes
in the system). This lower bound holds even in rings. We present a new
deterministic (non-silent) self-stabilizing protocol for n-node rings that uses
only O(\log\log n) memory bits per node, and stabilizes in O(n\log^2 n) rounds.
Our protocol has several attractive features that make it suitable for
practical purposes. First, the communication model fits with the model used by
existing compilers for real networks. Second, the size of the ring (or any
upper bound on this size) needs not to be known by any node. Third, the node
identifiers can be of various sizes. Finally, no synchrony assumption, besides
a weakly fair scheduler, is assumed. Therefore, our result shows that, perhaps
surprisingly, trading silence for exponential improvement in term of memory
space does not come at a high cost regarding stabilization time or minimal
assumptions.


title: What are the fundamental structures of concurrency? We still don't know!

abstract:
  Process algebra has been successful in many ways; but we don't yet see the
lineaments of a fundamental theory. Some fleeting glimpses are sought from
Petri Nets, physics and geometry.


title:
The dimensions and Euler characteristics of M. Kontsevich's graph
  complexes

abstract:
  We provide a generating function for the (graded) dimensions of M.
Kontsevich's graph complexes of ordinary graphs. This generating function can
be used to compute the Euler characteristic in each loop order. Furthermore, we
show that graphs with multiple edges can be omitted from these graph complexes.


title: Multiple Ionization under Strong XUV to X-ray Radiation

abstract:
  We review the main aspects of multiple photoionization processes in atoms
exposed to intense, short wavelength radiation. The main focus is the
theoretical framework for the description of such processes as well as the
conditions under which direct multiphoton multiple ionization processes can
dominate over the sequential ones. We discuss in detail the mechanisms
available in different wavelength ranges from the infrared to the hard X-rays.
The effect of field fluctuations, present at this stage in all SASE
free-electron-laser (FEL) facilities, as well as the effect of the interaction
volume integration, are also discussed.


title: Potentially Du Bois spaces

abstract:
  We investigate properties of potentially Du Bois singularities, that is,
those that occur on the underlying space of a Du Bois pair. We show that a
normal variety $X$ with potentially Du Bois singularities and Cartier canonical
divisor $K_X$ is necessarily log canonical, and hence Du Bois. As an immediate
corollary, we obtain the Lipman-Zariski conjecture for varieties with
potentially Du Bois singularities.
  We also show that for a normal surface singularity, the notions of Du Bois
and potentially Du Bois singularities coincide. In contrast, we give an example
showing that in dimension at least three, a normal potentially Du Bois
singularity $x \in X$ need not be Du Bois even if one assumes the canonical
divisor $K_X$ to be $\mathbb{Q}$-Cartier.


title: Ultrafilters maximal for finite embeddability

abstract:
  In [1] the authors showed some basic properties of a pre-order that arose in
combinatorial number theory, namely the finite embeddability between sets of
natural numbers, and they presented its generalization to ultrafilters, which
is related to the algebraical and topological structure of the Stone-\v{C}ech
compactification of the discrete space of natural numbers. In this present
paper we continue the study of these pre-orders. In particular, we prove that
there exist ultrafilters maximal for finite embeddability, and we show that the
set of such ultrafilters is the closure of the minimal bilateral ideal in the
semigroup $(\bN,\oplus)$, namely $\overline{K(\bN,\oplus)}$. As a consequence,
we easily derive many combinatorial properties of ultrafilters in
$\overline{K(\bN,\oplus)}$. We also give an alternative proof of our main
result based on nonstandard models of arithmetic.


title:
Dispersion modeling and analysis for multilayered open coaxial
  waveguides

abstract:
  This paper presents a detailed modeling and analysis regarding the dispersion
characteristics of multilayered open coaxial waveguides. The study is motivated
by the need of improved modeling and an increased physical understanding about
the wave propagation phenomena on very long power cables which has a potential
industrial application with fault localization and monitoring. The
electromagnetic model is based on a layer recursive computation of
axial-symmetric fields in connection with a magnetic frill generator excitation
that can be calibrated to the current measured at the input of the cable. The
layer recursive formulation enables a stable and efficient numerical
computation of the related dispersion functions as well as a detailed analysis
regarding the analytic and asymptotic properties of the associated
determinants. Modal contributions as well as the contribution from the
associated branch-cut (non-discrete radiating modes) are defined and analyzed.
Measurements and modeling of pulse propagation on an 82 km long HVDC power
cable are presented as a concrete example. In this example, it is concluded
that the contribution from the second TM mode as well as from the branch-cut is
negligible for all practical purposes. However, it is also shown that for
extremely long power cables the contribution from the branch-cut can in fact
dominate over the quasi-TEM mode for some frequency intervals. The main
contribution of this paper is to provide the necessary analysis tools for a
quantitative study of these phenomena.


title: The Gaia-ESO Survey: Kinematic structure in the Gamma Velorum Cluster

abstract:
  Context: A key science goal of the Gaia-ESO survey (GES) is to use the
kinematics of low-mass stars in young clusters to probe their dynamical
histories and how they populate the field as they become unbound. The
clustering of low-mass stars around the massive W-R binary gamma^2 Velorum was
one of the first GES targets. Aims: To empirically determine the radial
velocity (RV) precision of GES data, construct a kinematically unbiased sample
of cluster members and characterise their dynamical state. Methods: Targets
were selected from colour-magnitude diagrams and intermediate resolution
spectroscopy used to derive RVs and assess membership from the strength of the
Li6708A line. The RV distribution was analysed using a maximum likelihood
technique that accounts for unresolved binaries. Results: The GES RV precision
is about 0.25km/s and sufficient to resolve velocity structure in the low-mass
population around gamma^2 Vel. The structure is well fitted by two kinematic
components with roughly equal numbers of stars; the first has an intrinsic
dispersion of 0.34+/-0.16km/s, consistent with virial equilibrium. The second
has a broader dispersion of 1.60+/-0.37km/s and is offset from the first by
~2km/s. The first population is older by 1-2Myr based on a greater level of Li
depletion seen among its M-stars and is probably more centrally concentrated
around gamma^2 Vel. Conclusions: We consider several formation scenarios,
concluding that the two kinematic components are a bound remnant of the
original, denser cluster that formed gamma^2 Vel, and a dispersed population
from the wider Vela OB2 association, of which gamma^2 Vel is the most massive
member. The apparent youth of gamma^2 Vel compared to the older (>=10Myr)
low-mass population surrounding it suggests a scenario where the massive binary
formed in a clustered environment after the formation of the bulk of the
low-mass stars.[abridged]


title: Shaped extensions of singular spectrum analysis

abstract:
  Extensions of singular spectrum analysis (SSA) for processing of
non-rectangular images and time series with gaps are considered. A circular
version is suggested, which allows application of the method to the data given
on a circle or on a cylinder, e.g. cylindrical projection of a 3D ellipsoid.
The constructed Shaped SSA method with planar or circular topology is able to
produce low-rank approximations for images of complex shapes. Together with
Shaped SSA, a shaped version of the subspace-based ESPRIT method for frequency
estimation is developed. Examples of 2D circular SSA and 2D Shaped ESPRIT are
presented.


title:
A sub nrad beam pointing monitoring and stabilization system for
  controlling input beam jitter in GW interferometers

abstract:
  In this paper a simple and very effective control system to monitor and
suppress the beam jitter noise at the input of an optical system, called Beam
Pointing Control (BPC) system, will be described showing the theoretical
principle and an experimental demonstration for the application of large scale
gravitational wave interferometers, in particular for the Advanced Virgo
detector. For this purpose the requirements for the control accuracy and the
sensing noise will be computed by taking into account the Advanced Virgo
optical configuration and the outcomes will be compared with the experimental
measurement obtained in the laboratory. The system has shown unprecedented
performance in terms of control accuracy and sensing noise. The BPC system has
achieved a control accuracy of ~ $10^{-8}$ rad for the tilt and ~ $10^{-7}$ m
for the shift and a sensing noise of less than 1 nrad/$\sqrt{Hz}$ resulting
compliant with the Advance Virgo gravitational wave interferometer
requirements.


title: Homogeneous G-algebras II

abstract:
  G-algebras, or Groebner bases algebras, were considered by Levandovsky, these
algebras include very important families of algebras, like the Weyl algebras
and the universal enveloping algebra of a finite dimensional Lie algebra. These
algebras are not graded in a natural way, but they are filtered. Going to the
associated graded algebra is the standard way to study their properties. In a
previous paper we studied an homogeneous version of the G-algebras, which
results naturally graded, and through a des homogenization property, we obtain
an ordinary G-algebra. The main results in our first paper were the following:
Homogeneous G-algebras are Koszul of finite global dimension, Artin Schelter
regular, noetherian and have a Poincare Birkoff basis. We give the structure of
their Yoneda algebras by generators and relations. In the second part of the
paper we consider the quantum polynomial ring and prove, for the finitely
generated graded modules, cohomology formulas analogous to those we have in the
usual polynomial ring. In the third part we use the results of the previous
part to study the cohomology of the homogeneous G-algebras. Part four was
dedicated to the study of the relations between an homogeneous G-algebra B and
its des homogenization B/(Z-1)B=A, Applications to the study of finite
dimensional Lie algebras and Weyl algebras were given. In the last sections of
the paper we study the relations, at the level of modules, among the
homogenized algebra B, its graded localization B_{z}, the des homogenization
A=B/(Z-1)B and the Yoneda algebra B^{!}. In this paper we investigate the
relations among all these algebras at the level of derived categories.


title: Classical and motivic Adams charts

abstract:
  This document contains large-format Adams charts that compute 2-complete
stable homotopy groups, both in the classical context and in the motivic
context over C. The charts are essentially complete through the 61-stem and
contain partial results to the 70-stem. In the classical context, we believe
that these are the most accurate charts of their kind.
  We also include Adams charts for the motivic homotopy groups of the cofiber
of tau.