title: First results of X-shooter observations of IGR sources

abstract:
  X-shooter is a second generation ESO-VLT instrument that had its first light
in October 2009. It is a single object medium-resolution spectrograph whose
main feature is the capability of covering simultaneously in a single
observation the range from 3000 to 24000 Angstrom. This unique capability is
very well suited to investigate the complex spectra of the optical counterparts
of X/gamma ray sources which usually display signatures of different components
in emission and absorption. In July 2012 we observed with X-shooter a small
sample of counterparts of bright IGR sources in order to better determine their
physical properties. We present the first results of these observations.


title: $\alpha$-Large Families and Applications to Banach Space Theory

abstract:
  The notion of $\alpha$-large families of finite subsets of an infinite set is
defined for every countable ordinal number $\alpha$, extending the known notion
of large families. The definition of the $\alpha$-large families is based on
the transfinite hierarchy of the Schreier families $\mathcal{S}_{\alpha},
\alpha<\omega_1$. We prove the existence of such families on the cardinal
number $2^{\aleph_0}$ and we study their properties. As an application, based
on those families we construct a reflexive space
$\mathfrak{X}_{2^{\aleph_0}}^{\alpha}$, $\alpha<\omega_1$ with density the
continuum, such that every bounded non norm convergent sequence $\{x_k\}_k$ has
a subsequence generating $\ell_1^{\alpha}$ as a spreading model.


title:
Langmuir dark solitons in dense ultrarelativistic electron-positron
  gravito-plasma in pulsar magnetosphere

abstract:
  Nonlinear propagation of electrostatic modes in ultrarelativistic dense
elelectron-positron gravito-plasma at the polar cap region of pulsar
magnetosphere is considered. A nonlinear Schr\"{o}dinger equation is obtained
from the reductive perturbation method which predicts the existence of Langmuir
dark solitons. Relevance of the propagating dark solitons to the pulsar radio
emission is discussed.


title:
The flattening of globular clusters: internal rotation or velocity
  anisotropy?

abstract:
  Internal rotation is considered to play a major role in determining the
structure and dynamics of some globular clusters. We present a dynamical
analysis of the photometry and three-dimensional kinematics of 47 Tuc and omega
Cen, by means of a new family of self-consistent axisymmetric rotating models.
The combined use of line-of-sight velocities and proper motions allows us to
obtain a global description of the internal dynamical structure of the objects
together with an estimate of their dynamical distances. The well-relaxed
cluster 47 Tuc is very well interpreted by our dynamical models; in particular,
internal rotation is found to explain the observed morphology. For the
partially relaxed cluster omega Cen, the selected model provides a good
representation of its complex three-dimensional kinematics, in general
qualitative agreement with the observed anisotropy profile, which is
characterized by tangential anisotropy in the outer parts; discrepancies are
found between the observed and the expected ellipticity profile and are
ascribed to the presence of a high degree of radial anisotropy in the
intermediate region and to its interplay with rotation.


title:
Longitudinal dielectric permeability into quantum degenerate plasma with
  frequency of collisions proportional to the module of a wave vector

abstract:
  Formulas for the longitudinal dielectric permeability in quantum degenerate
collisional plasma with the frequency of collisions proportional to the module
of the wave vector, in Mermin's approach, are received. Equation of
Shr\"{o}dinger - Boltzmann with integral of collisions relaxation type in
Mermin's approach is applied. It is spent numerical and graphic comparison of
the real and imaginary parts of dielectric function of non-degenerate and
maxwellian collisional quantum plasma with a constant and a variable
frequencies of collisions. It is shown, that the longitudinal dielectric
function weakly depends on a wave vector.


title:
Magnetic order and low-energy excitations in the quasi-one-dimensional
  antiferromagnet CuSe$_2$O$_5$ with staggered fields

abstract:
  Ground state and low-energy excitations of the quasi-one-dimensional
antiferromagnet CuSe$_2$O$_5$ were experimentally studied using bulk
magnetization, neutron diffraction, muon spin relaxation and antiferromagnetic
resonance measurements. Finite interchain interactions promote long-range
antiferromagnetic order below $T_N=17$ K. The derived spin canted structure is
characterized by the magnetic propagation vector $\mathbf{k}=(1, 0, 0)$ and the
reduced magnetic moment $\bm{m}=[0.13(7), 0.50(1), 0.00(8)]\mu_B$. The values
of the magnetic anisotropies determined from the field and angular dependencies
of the antiferromagnetic resonance comply well with a previous electron
paramagnetic resonance study and correctly account for the observed magnetic
ground state and spin-flop transition.


title: Stick-Slip Mode of Boundary Friction as the First-Order Phase Transition

abstract:
  A tribological system consisting of two contacting blocks has been
considered. One of them is arranged between two springs, the other is driven
periodically. The kinetics of the system has been studied in the boundary
friction mode, when an ultrathin lubricant film is contained between the
atomically smooth surfaces. In order to describe the film state, the expression
for the free energy density is used in the form of an expansion in a power
series in the order parameter, the latter being reduced to the shear modulus of
a lubricant. The stick-slip mode is shown to be realized in a wide range of
parameters, being a result of the periodic first-order phase transitions
between kinetic friction regimes. The behavior of the system governed by
internal and external parameters has been predicted.


title: The Packing Coloring of Distance Graphs $D(k,t)$

abstract:
  The packing chromatic number $\chi_{\rho}(G)$ of a graph $G$ is the smallest
integer $p$ such that vertices of $G$ can be partitioned into disjoint classes
$X_{1}, ..., X_{p}$ where vertices in $X_{i}$ have pairwise distance greater
than $i$. For $k < t$ we study the packing chromatic number of infinite
distance graphs $D(k, t)$, i.e. graphs with the set $\Z$ of integers as vertex
set and in which two distinct vertices $i, j \in \Z$ are adjacent if and only
if $|i - j| \in \{k, t\}$.
  We generalize results by Ekstein et al. for graphs $D (1, t)$. For
sufficiently large $t$ we prove that $\chi_{\rho}(D(k, t)) \leq 30$ for both
$k$, $t$ odd, and that $\chi_{\rho}(D(k, t)) \leq 56$ for exactly one of $k$,
$t$ odd. We also give some upper and lower bounds for $\chi_{\rho}(D(k, t))$
with small $k$ and $t$.
  Keywords: distance graph; packing coloring; packing chromatic number


title:
A new determination of the charm mass from the non-analytic
  reconstruction of the heavy quark correlator

abstract:
  Using the new non-analytic reconstruction method obtained from Mellin-Barnes
properties, one can extract the value $m_c(\bar{\text{MS}}) = 1.12 \pm 0.08
\;\; \text{GeV}$ from experimental data of the radiation-corrected measured
hadronic cross section to the calculated lowest-order cross section for muon
pair production in the heavy-quark approximation.


title:
Multi-Robot Informative Path Planning for Active Sensing of
  Environmental Phenomena: A Tale of Two Algorithms

abstract:
  A key problem of robotic environmental sensing and monitoring is that of
active sensing: How can a team of robots plan the most informative observation
paths to minimize the uncertainty in modeling and predicting an environmental
phenomenon? This paper presents two principled approaches to efficient
information-theoretic path planning based on entropy and mutual information
criteria for in situ active sensing of an important broad class of
widely-occurring environmental phenomena called anisotropic fields. Our
proposed algorithms are novel in addressing a trade-off between active sensing
performance and time efficiency. An important practical consequence is that our
algorithms can exploit the spatial correlation structure of Gaussian
process-based anisotropic fields to improve time efficiency while preserving
near-optimal active sensing performance. We analyze the time complexity of our
algorithms and prove analytically that they scale better than state-of-the-art
algorithms with increasing planning horizon length. We provide theoretical
guarantees on the active sensing performance of our algorithms for a class of
exploration tasks called transect sampling, which, in particular, can be
improved with longer planning time and/or lower spatial correlation along the
transect. Empirical evaluation on real-world anisotropic field data shows that
our algorithms can perform better or at least as well as the state-of-the-art
algorithms while often incurring a few orders of magnitude less computational
time, even when the field conditions are less favorable.


title: Death and resurrection of the zeroth principle of thermodynamics

abstract:
  The zeroth principle of thermodynamics in the form "temperature is uniform at
equilibrium" is notoriously violated in relativistic gravity. Temperature
uniformity is often derived from the maximization of the total number of
microstates of two interacting systems under energy exchanges. Here we discuss
a generalized version of this derivation, based on informational notions, which
remains valid in the general context. The result is based on the observation
that the time taken by any system to move to a distinguishable (nearly
orthogonal) quantum state is a universal quantity that depends solely on the
temperature. At equilibrium the net information flow between two systems must
vanish, and this happens when two systems transit the same number of
distinguishable states in the course of their interaction.


title: Massive Binary Stars and Self-Enrichment of Globular Clusters

abstract:
  Globular clusters contain many stars with surface abundance patterns
indicating contributions from hydrogen burning products, as seen in the
anti-correlated elemental abundances of e.g. sodium and oxygen, and magnesium
and aluminium. Multiple generations of stars can explain this phenomenon, with
the second generation forming from a mixture of pristine gas and ejecta from
the first generation. We show that massive binary stars may be a source of much
of the material that makes this second generation of stars. Mass transfer in
binaries is often non-conservative and the ejected matter moves slowly enough
that it can remain inside a globular cluster and remain available for
subsequent star formation. Recent studies show that there are more short-period
massive binaries than previously thought, hence also more stars that interact
and eject nuclear-processed material.


title:
Beam dynamics performances and applications of a low-energy
  electron-beam magnetic bunch compressor

abstract:
  Many front-end applications of electron linear accelerators rely on the
production of temporally-compressed bunches. The shortening of electron bunches
is often realized with magnetic bunch compressors located in high-energy
sections of accelerators. Magnetic compression is subject to collective effects
including space charge and self interaction via coherent synchrotron radiation.
In this paper we explore the application of magnetic compression to low-energy
($\sim 40$ MeV), high-charge (nC) electron bunches with low normalized
transverse emittances ($< 5$ $\mu$m).


title:
Robustness of predator-prey models for confinement regime transitions in
  fusion plasmas

abstract:
  Energy transport and confinement in tokamak fusion plasmas is usually
determined by the coupled nonlinear interactions of small-scale drift
turbulence and larger scale coherent nonlinear structures, such as zonal flows,
together with free energy sources such as temperature gradients.
Zero-dimensional models, designed to embody plausible physical narratives for
these interactions, can help identify the origin of enhanced energy confinement
and of transitions between confinement regimes. A prime zero-dimensional
paradigm is predator-prey or Lotka-Volterra. Here we extend a successful
three-variable (temperature gradient; microturbulence level; one class of
coherent structure) model in this genre [M A Malkov and P H Diamond, Phys.
Plasmas 16, 012504 (2009)], by adding a fourth variable representing a second
class of coherent structure. This requires a fourth coupled nonlinear ordinary
differential equation. We investigate the degree of invariance of the
phenomenology generated by the model of Malkov and Diamond, given this
additional physics. We study and compare the long-time behaviour of the
three-equation and four-equation systems, their evolution towards the final
state, and their attractive fixed points and limit cycles. We explore the
sensitivity of paths to attractors. It is found that, for example, an
attractive fixed point of the three-equation system can become a limit cycle of
the four-equation system. Addressing these questions - which we together refer
to as "robustness" for convenience, is particularly important for models which,
as here, generate sharp transitions in the values of system variables which may
replicate some key features of confinement transitions. Our results help
establish the robustness of the zero-dimensional model approach to capturing
observed confinement phenomenology in tokamak fusion plasmas.


title: Population of persistent high mass X-ray binaries in the Milky Way

abstract:
  We present results of the study of persistent high mass X-ray binaries
(HMXBs) in the Milky Way, obtained from the deep INTEGRAL Galactic plane
survey. This survey provides us a new insight into the population of high mass
X-ray binaries because almost half of the whole sample consists of sources
discovered with INTEGRAL. It is demonstrated for the first time that the
majority of persistent HMXBs have supergiant companions and their luminosity
function steepens somewhere around ~2x10^{36} erg/s. We show that the spatial
density distribution of HMXBs correlates well with the star formation rate
distribution in the Galaxy. The vertical distribution of HMXBs has a
scale-height h~85 pc, that is somewhat larger than the distribution of young
stars in the Galaxy. We propose a simple toy model, which adequately describes
general properties of HMXBs in which neutron stars accrete a matter from the
wind of the its companion (wind-fed NS-HMXBs population). Using the elaborated
model we argue that a flaring activity of so-called supergiant fast X-ray
transients, the recently recognized sub-sample of HMXBs, is likely related with
the magnetic arrest of their accretion.


title: Fast microwave beam splitters from superconducting resonators

abstract:
  Coupled superconducting transmission line resonators have applications in
quantum information processing and fundamental quantum mechanics. A particular
example is the realization of fast beam splitters, which however is hampered by
two-mode squeezer terms. Here, we experimentally study superconducting
microstrip resonators which are coupled over one third of their length. By
varying the position of this coupling region we can tune the strength of the
two-mode squeezer coupling from 2.4% to 12.9% of the resonance frequency of
5.44GHz. Nevertheless, the beam splitter coupling rate for maximally suppressed
two-mode squeezing is 810MHz, enabling the construction of a fast and pure beam
splitter.


title: Measure Transformed Independent Component Analysis

abstract:
  In this paper we derive a new framework for independent component analysis
(ICA), called measure-transformed ICA (MTICA), that is based on applying a
structured transform to the probability distribution of the observation vector,
i.e., transformation of the probability measure defined on its observation
space. By judicious choice of the transform we show that the separation matrix
can be uniquely determined via diagonalization of several measure-transformed
covariance matrices. In MTICA the separation matrix is estimated via
approximate joint diagonalization of several empirical measure-transformed
covariance matrices. Unlike kernel based ICA techniques where the
transformation is applied repetitively to some affine mappings of the
observation vector, in MTICA the transformation is applied only once to the
probability distribution of the observations. This results in performance
advantages and reduced implementation complexity. Simulations demonstrate the
advantages of the proposed approach as compared to other existing
state-of-the-art methods for ICA.


title:
Solution of Leray's problem for stationary Navier-Stokes equations in
  plane and axially symmetric spatial domains

abstract:
  We study the nonhomogeneous boundary value problem for the Navier-Stokes
equations of steady motion of a viscous incompressible fluid in arbitrary
bounded multiply connected plane or axially-symmetric spatial domains. We prove
that this problem has a solution under the sole necessary condition of zero
total flux through the boundary. The problem was formulated by Jean Leray 80
years ago. The proof of the main result uses Bernoulli's law for a weak
solution to the Euler equations.


title: Complex b-manifolds

abstract:
  A complex $b$-structure on a manifold $\M$ with boundary is an involutive
subbundle $\bT^{0,1}\M$ of the complexification of $\bT\M$ with the property
that $\C\bT\M = \bT^{0,1}\M + \bar{\bT^{0,1}\M}$ as a direct sum; the interior
of $\M$ is a complex manifold. The complex $b$-structure determines an elliptic
complex of $b$-operators and induces a rich structure on the boundary of $\M$.
We study the cohomology of the indicial complex of the $b$-Dolbeault complex.


title:
Efficient Estimation of Band Gaps in Transition-Metal Oxides and
  Chalcogenides using Density Functional Theory

abstract:
  The performance of two modern density-functionals, HSE06 and TB-mBJ, on
predicting electronic structures of metal oxides, chalcogenides and nitrides,
is studied in terms of band gaps, band structure and projected
density-of-states. Contrary to GGA, hybrid functionals and GGA+U, both new
functionals are able to predict band gaps with an appreciable accuracy of 25%
and thus allow the screening of various classes of (mixed) metal oxides at
modest computational cost. The calculated electronic structures are largely
unaffected by the choice of basis functions and software implementation.


title: Vanishing ideals over complete multipartite graphs

abstract:
  We study the vanishing ideal of the parametrized algebraic toric associated
to the complete multipartite graph $\G=\mathcal{K}_{\alpha_1,...,\alpha_r}$
over a finite field of order $q$. We give an explicit family of binomial
generators for this lattice ideal, consisting of the generators of the ideal of
the torus, (referred to as type I generators), a set of quadratic binomials
corresponding to the cycles of length 4 in $\G$ and which generate the
\emph{toric algebra of $\G$} (type II generators) and a set of binomials of
degree $q-1$ obtained combinatorially from $\G$ (type III generators). Using
this explicit family of generators of the ideal, we show that its
Castelnuovo--Mumford regularity is equal to
$\max\set{\alpha_1(q-2),...,\alpha_r(q-2), \lceil (n-1)(q-2)/2\rceil}$, where
$n=\alpha_1+... + \alpha_r$.


title:
Bifurcations and dynamics in convection with temperature-dependent
  viscosity in the presence of the O(2) symmetry

abstract:
  We focus the study of a convection problem in a 2D setup in the presence of
the O(2) symmetry. The viscosity in the fluid depends on the temperature as it
changes its value abruptly in an interval around a temperature of transition.
The influence of the viscosity law on the morphology of the plumes is examined
for several parameter settings, and a variety of shapes ranging from spout to
mushroom shaped is found. We explore the impact of the symmetry on the time
evolution of this type of fluid, and find solutions which are greatly
influenced by its presence: at a large aspect ratio and high Rayleigh numbers,
traveling waves, heteroclinic connections and chaotic regimes are found. These
solutions, which are due to the symmetry presence, have not been previously
described in the context of temperature dependent viscosities. However,
similarities are found with solutions described in other contexts such as flame
propagation problems or convection problems with constant viscosity also under
the presence of the O(2) symmetry, thus confirming the determining role of the
symmetry in the dynamics.


title:
Tangential force, Frictional Torque and Heating Rate of a Small Neutral
  Rotating Particle Moving through the Equilibrium Background Radiation

abstract:
  For the first time, based on the fluctuation-electromagnetic theory, we have
calculated the drug force, the radiation heat flux and the frictional torque on
a small rotating particle moving at a relativistic velocity through the
equilibrium background radiation (photon gas). The particle and background
radiation are characterized by different temperatures corresponding to the
local thermodynamic equilibrium in their own reference frames.


title:
Electrostatic tailoring of magnetic interference in quantum point
  contact ballistic Josephson junctions

abstract:
  The magneto-electrostatic tailoring of the supercurrent in quantum point
contact ballistic Josephson junctions is demonstrated. An etched InAs-based
heterostructure is laterally contacted to superconducting niobium leads and the
existence of two etched side gates permits, in combination with the application
of a perpendicular magnetic field, to modify continuously the magnetic
interference pattern by depleting the weak link. For wider junctions the
supercurrent presents a Fraunhofer-like interference pattern with periodicity
h/2e whereas by shrinking electrostatically the weak link, the periodicity
evolves continuously to a monotonic decay. These devices represent novel
tunable structures that might lead to the study of the elusive Majorana
fermions.


title:
Probing the Inner Regions of Protoplanetary Disks with CO Absorption
  Line Spectroscopy

abstract:
  Carbon monoxide (CO) is the most commonly used tracer of molecular gas in the
inner regions of protoplanetary disks. CO can be used to constrain the
excitation and structure of the circumstellar environment. Absorption line
spectroscopy provides an accurate assessment of a single line-of-sight through
the protoplanetary disk system, giving more straightforward estimates of column
densities and temperatures than CO and molecular hydrogen emission line
studies. We analyze new observations of ultraviolet CO absorption from the
Hubble Space Telescope along the sightlines to six classical T Tauri stars. Gas
velocities consistent with the stellar velocities, combined with the
moderate-to-high disk inclinations, argue against the absorbing CO gas
originating in a fast-moving disk wind. We conclude that the far-ultraviolet
observations provide a direct measure of the disk atmosphere or possibly a slow
disk wind. The CO absorption lines are reproduced by model spectra with column
densities in the range N(^{12}CO) ~ 10^{16} - 10^{18} cm^{-2} and N(^{13}CO) ~
10^{15} - 10^{17} cm^{-2}, rotational temperatures T_{rot}(CO) ~ 300 - 700 K,
and Doppler b-values, b ~ 0.5 - 1.5 km s^{-1}. We use these results to
constrain the line-of-sight density of the warm molecular gas (n_{CO} ~ 70 -
4000 cm^{-3}) and put these observations in context with protoplanetary disk
models.


title: Benchmarking community detection methods on social media data

abstract:
  Benchmarking the performance of community detection methods on empirical
social network data has been identified as critical for improving these
methods. In particular, while most current research focuses on detecting
communities in data that has been digitally extracted from large social media
and telecommunications services, most evaluation of this research is based on
small, hand-curated datasets. We argue that these two types of networks differ
so significantly that by evaluating algorithms solely on the former, we know
little about how well they perform on the latter. To address this problem, we
consider the difficulties that arise in constructing benchmarks based on
digitally extracted network data, and propose a task-based strategy which we
feel addresses these difficulties. To demonstrate that our scheme is effective,
we use it to carry out a substantial benchmark based on Facebook data. The
benchmark reveals that some of the most popular algorithms fail to detect
fine-grained community structure.


title:
Average and dispersion of the luminosity-redshift relation in the
  concordance model

abstract:
  Starting from the luminosity-redshift relation recently given up to second
order in the Poisson gauge, we calculate the effects of the realistic
stochastic background of perturbations of the so-called concordance model on
the combined light-cone and ensemble average of various functions of the
luminosity distance, and on their variance, as functions of redshift. We apply
a gauge-invariant light-cone averaging prescription which is free from infrared
and ultraviolet divergences, making our results robust with respect to changes
of the corresponding cutoffs. Our main conclusions, in part already anticipated
in a recent letter for the case of a perturbation spectrum computed in the
linear regime, are that such inhomogeneities not only cannot avoid the need for
dark energy, but also cannot prevent, in principle, the determination of its
parameters down to an accuracy of order $10^{-3}-10^{-5}$, depending on the
averaged observable and on the regime considered for the power spectrum.
However, taking into account the appropriate corrections arising in the
non-linear regime, we predict an irreducible scatter of the data approaching
the 10% level which, for limited statistics, will necessarily limit the
attainable precision. The predicted dispersion appears to be in good agreement
with current observational estimates of the distance-modulus variance due to
Doppler and lensing effects (at low and high redshifts, respectively), and
represents a challenge for future precision measurements.


title:
Balancing time-varying demand-supply in distribution networks: an
  internal model approach

abstract:
  The problem of load balancing in a distribution network under unknown time-
varying demand and supply is studied. A set of distributed controllers which
regulate the amount of flow through the edges is designed to guarantee
convergence of the solution to the steady state solution. The results are then
extended to a class of nonlinear systems and compared with existing results.
Incremental passivity and internal model are the main analytical tools.


title: On the growth of torsion in the cohomology of arithmetic groups

abstract:
  In this paper we consider certain families of arithmetic subgroups of
SO^0(p,q) and SL_3(R), respectively. We study the cohomology of such arithmetic
groups with coefficients in arithmetically defined modules. We show that for
natural sequences of such modules the torsion in the cohomology grows
exponentially.


title:
Right-Handed Neutrino Production at Finite Temperature: Radiative
  Corrections, Soft and Collinear Divergences

abstract:
  The production and decay rate of massive sterile neutrinos at finite
temperature receives next-to-leading order corrections from the gauge
interactions of lepton and Higgs doublets. Using the Closed-Time-Path approach,
we demonstrate that the perturbatively obtained inclusive rate is finite. For
this purpose, we show that soft, collinear and Bose divergences cancel when
adding the tree-level rates from 1<->3 and 2<->2 processes to vertex and
wave-function corrections to 1<->2 processes. These results hold for a general
momentum of the sterile neutrino with respect to the plasma frame. Moreover,
they do not rely on non-relativistic approximations, such that the full
quantum-statistical effects are accounted for to the given order in
perturbation theory. While the neutrino production rate is of relevance for
Leptogenesis, the proposed methods may as well be suitable for application to a
more general class of relativistic transport phenomena.


title: Explicit MBR All-Symbol Locality Codes

abstract:
  Node failures are inevitable in distributed storage systems (DSS). To enable
efficient repair when faced with such failures, two main techniques are known:
Regenerating codes, i.e., codes that minimize the total repair bandwidth; and
codes with locality, which minimize the number of nodes participating in the
repair process. This paper focuses on regenerating codes with locality, using
pre-coding based on Gabidulin codes, and presents constructions that utilize
minimum bandwidth regenerating (MBR) local codes. The constructions achieve
maximum resilience (i.e., optimal minimum distance) and have maximum capacity
(i.e., maximum rate). Finally, the same pre-coding mechanism can be combined
with a subclass of fractional-repetition codes to enable maximum resilience and
repair-by-transfer simultaneously.


title: Safe Schedulability of Bounded-Rate Multi-Mode Systems

abstract:
  Bounded-rate multi-mode systems (BMMS) are hybrid systems that can switch
freely among a finite set of modes, and whose dynamics is specified by a finite
number of real-valued variables with mode-dependent rates that can vary within
given bounded sets. The schedulability problem for BMMS is defined as an
infinite-round game between two players---the scheduler and the
environment---where in each round the scheduler proposes a time and a mode
while the environment chooses an allowable rate for that mode, and the state of
the system changes linearly in the direction of the rate vector. The goal of
the scheduler is to keep the state of the system within a pre-specified safe
set using a non-Zeno schedule, while the goal of the environment is the
opposite. Green scheduling under uncertainty is a paradigmatic example of BMMS
where a winning strategy of the scheduler corresponds to a robust
energy-optimal policy. We present an algorithm to decide whether the scheduler
has a winning strategy from an arbitrary starting state, and give an algorithm
to compute such a winning strategy, if it exists. We show that the
schedulability problem for BMMS is co-NP complete in general, but for two
variables it is in PTIME. We also study the discrete schedulability problem
where the environment has only finitely many choices of rate vectors in each
mode and the scheduler can make decisions only at multiples of a given clock
period, and show it to be EXPTIME-complete.


title:
Effect of Power Losses on Self-Focusing of High Intensity Laser Beam in
  Gases

abstract:
  A theoretical study of power loss from periphery of an ultrashort pulse laser
beam and temporally resolved defocussing produced by laser induced plasma are
performed using paraxial approximation. Our analysis incorporate consideration
of spatial distribution of the laser beam irradiance and the results show that
substantial power losses (10%-80%) occur from the beam periphery limiting
length of a filament. It was also shown that generally accepted concept of
self-focusing critical power is inconsistent with consideration of self-induced
refraction of spatially distributed laser beam. A new criterion for
self-focusing and hypothesis for multiple filamentation are proposed.


title: Quasiclassical theory of disordered multi-channel Majorana quantum wires

abstract:
  Multi-channel spin-orbit quantum wires, when subjected to a magnetic field
and proximity coupled to s-wave superconductor, may support Majorana states. We
study what happens to these systems in the presence of disorder. Inspired by
the widely established theoretical methods of mesoscopic superconductivity, we
develop a la Eilenberger a quasiclassical approach to topological nanowires
valid in the limit of strong spin-orbit coupling. We find that the "Majorana
number", distinguishing between the state with Majorana fermion (symmetry class
B) and no Majorana (class D), is given by the product of two Pfaffians of
gapped quasiclassical Green's functions fixed by right and left terminals
connected to the wire. A numerical solution of the Eilenberger equations
reveals that the class D disordered quantum wires are prone to the formation of
the zero-energy anomaly (class D impurity spectral peak) in the local density
of states which shares the key features of the Majorana peak. In this way we
confirm the robustness of our previous conclusions [Phys. Rev. Lett. 109,
227005 (2012)] on a more restrictive system setup. Generally speaking, we find
that the quasiclassical approach provides a highly efficient means to address
disordered class D superconductors both in the presence and absence of
topological structures.


title: Homotopy of area decreasing maps by mean curvature flow

abstract:
  Let $f:M\to N$ be a smooth area decreasing map between two Riemannian
manifolds $(M,\gm)$ and $(N,\gn)$. Under weak and natural assumptions on the
curvatures of $(M,\gm)$ and $(N,\gn)$, we prove that the mean curvature flow
provides a smooth homotopy of $f$ to a constant map.


title:
Multi-Way Information Exchange Over Completely-Connected Interference
  Networks with a Multi-Antenna Relay

abstract:
  This paper considers a fully-connected interference network with a relay in
which multiple users equipped with a single antenna want to exchange multiple
unicast messages with other users in the network by sharing the relay equipped
with multiple antennas. For such a network, the degrees of freedom (DoF) are
derived by considering various message exchange scenarios: a multi-user
fully-connected Y channel, a two-pair two-way interference channel with the
relay, and a two-pair two-way X channel with the relay. Further, considering
distributed relays employing a single antenna in the two-way interference
channel and the three-user fully-connected Y channel, achievable sum-DoF are
also derived in the two-way interference channel and the three-user
fully-connected Y channel. A major implication of the derived DoF results is
that a relay with multiple antennas or multiple relays employing a single
antenna increases the capacity scaling law of the multi-user interference
network when multiple directional information flows are considered, even if the
networks are fully-connected and all nodes operate in half-duplex. These
results reveal that the relay is useful in the multi-way interference network
with practical considerations.


title: Incomplete Transition Complexity of Basic Operations on Finite Languages

abstract:
  The state complexity of basic operations on finite languages (considering
complete DFAs) has been in studied the literature. In this paper we study the
incomplete (deterministic) state and transition complexity on finite languages
of boolean operations, concatenation, star, and reversal. For all operations we
give tight upper bounds for both description measures. We correct the published
state complexity of concatenation for complete DFAs and provide a tight upper
bound for the case when the right automaton is larger than the left one. For
all binary operations the tightness is proved using family languages with a
variable alphabet size. In general the operational complexities depend not only
on the complexities of the operands but also on other refined measures.


title:
VLA Observations of DG Tau's Radio Jet: A highly collimated thermal
  outflow

abstract:
  The active young protostar DG Tau has an extended jet that has been well
studied at radio, optical, and X-ray wavelengths. We report sensitive new VLA
full-polarization observations of the core and jet between 5 GHz and 8 GHz. Our
high angular resolution observation at 8 GHz clearly shows an unpolarized inner
jet with a size 42 AU (0.35") extending along a position angle similar to the
optical-X ray outer jet. Using our nearly coeval 2012 VLA observations, we find
a spectral-index=+0.46+/-0.05, which combined with the lack of polarization, is
consistent with bremsstrahlung (free-free) emission, with no evidence for a
non-thermal coronal component. By identifying the end of the radio jet as the
optical depth unity surface, and calculating the resulting emission measure, we
find our radio results are in agreement with previous optical line studies of
electron density and consequent mass-loss rate. We also detect a weak radio
knot at 5 GHz located 7" from the base of the jet, coincident with the inner
radio knot detected by Rodriguez et al. (2012) in 2009 but at lower surface
brightness. We interpret this as due to expansion of post-shock ionized gas in
the three years between observations.


title:
Applying an accurate spherical model to gamma-ray burst afterglow
  observations

abstract:
  We present results of model fits to afterglow data sets of GRB970508,
GRB980703 and GRB070125, characterized by long and broadband coverage. The
model assumes synchrotron radiation (including self-absorption) from a
spherical adiabatic blast wave and consists of analytic flux prescriptions
based on numerical results. For the first time it combines the accuracy of
hydrodynamic simulations through different stages of the outflow dynamics with
the flexibility of simple heuristic formulas. The prescriptions are especially
geared towards accurate description of the dynamical transition of the outflow
from relativistic to Newtonian velocities in an arbitrary power-law density
environment. We show that the spherical model can accurately describe the data
only in the case of GRB970508, for which we find a circumburst medium density
consistent with a stellar wind. We investigate in detail the implied spectra
and physical parameters of that burst. For the microphysics we show evidence
for equipartition between the fraction of energy density carried by
relativistic electrons and magnetic field. We also find that for the blast wave
to be adiabatic, the fraction of electrons accelerated at the shock has to be
smaller than 1. We present best-fit parameters for the afterglows of all three
bursts, including uncertainties in the parameters of GRB970508, and compare the
inferred values to those obtained by different authors.


title: Rooted Trees with Probabilities Revisited

abstract:
  Rooted trees with probabilities are convenient to represent a class of random
processes with memory. They allow to describe and analyze variable length codes
for data compression and distribution matching. In this work, the Leaf-Average
Node-Sum Interchange Theorem (LANSIT) and the well-known applications to path
length and leaf entropy are re-stated. The LANSIT is then applied to
informational divergence. Next, the differential LANSIT is derived, which
allows to write normalized functionals of leaf distributions as an average of
functionals of branching distributions. Joint distributions of random variables
and the corresponding conditional distributions are special cases of leaf
distributions and branching distributions. Using the differential LANSIT,
Pinsker's inequality is formulated for rooted trees with probabilities, with an
application to the approximation of product distributions. In particular, it is
shown that if the normalized informational divergence of a distribution and a
product distribution approaches zero, then the entropy rate approaches the
entropy rate of the product distribution.


title:
An exact mapping between the states of arbitrary N-level quantum systems
  and the positions of classical coupled oscillators

abstract:
  The dynamics of states representing arbitrary N-level quantum systems,
including dissipative systems, can be modelled exactly by the dynamics of
classical coupled oscillators. There is a direct one-to-one correspondence
between the quantum states and the positions of the oscillators. Quantum
coherence, expectation values, and measurement probabilities for system
observables can therefore be realized from the corresponding classical states.
The time evolution of an N-level system is represented as the rotation of a
real state vector in hyperspace, as previously known for density matrix states
but generalized here to Schrodinger states. A single rotor in n dimensions is
then mapped directly to n oscillators in one physical dimension. The number of
oscillators needed to represent N-level systems scales linearly with N for
Schrodinger states, in contrast to N^2 for the density matrix formalism.
Although the well-known equivalence (SU(2), SO(3) homomorphism) of 2-level
quantum dynamics to a rotation in real, physical space cannot be generalized to
arbitrary N-level systems, representing quantum dynamics by a system of coupled
harmonic oscillators in one physical dimension is general for any N. Values for
the classical coupling constants are readily obtained from the system
Hamiltonian, allowing construction of classical mechanical systems that can
provide visual insight into the dynamics of abstract quantum systems as well as
a metric for characterizing the interface between quantum and classical
mechanics.


title: Deep optical imaging of the gamma-ray pulsar J1048-5832 with the VLT

abstract:
  (abridged) PSR J1048-5832 is a young Vela-like pulsar that was recently
detected in gamma-rays with Fermi, and also in X-rays with Chandra and
XMM-Newton. It powers a compact PWN visible in X-rays. We present deep optical
observations with the ESO Very Large Telescope to search for optical
counterparts of the pulsar and its nebula and to explore their multi-wavelength
emission properties. The data were obtained in V and R bands and compared with
archival data in other spectral domains. We do not detect the pulsar in the
optical and derive informative upper limits of R > 28.1 mag and V > 28.4 mag
for its brightness. Using a red-clump star method, we estimate an interstellar
extinction towards the pulsar of 2 mag, which is consistent with the absorbing
column density derived form X-rays. The respective distance agrees with the
dispersion measure distance. We reanalyse the Chandra X-ray data and compare
the dereddened upper limits with the unabsorbed X-ray spectrum of the pulsar.
We find that regarding its optical-X-ray spectral properties this gamma-ray
pulsar is not distinct from other pulsars detected in both ranges. However,
like the Vela pulsar, it is very inefficient in the optical and X-rays. Among a
dozen optical sources overlapping with the pulsar X-ray nebula we find one with
V = 26.9 and R = 26.3 mag, whose colour is slightly bluer then that of the
field stars and consistent with the peculiar colours typical for pulsar nebula
features. It positionally coincides with a relatively bright feature of the
pulsar X-ray nebula, resembling the Crab wisp and locating in 2 arcsec from the
pulsar. We suggest this source as a counterpart candidate to the feature. Based
on the substantial interstellar extinction towards the pulsar and its optical
inefficiency, further optical studies should be carried out at longer
wavelengths.


title:
Decomposition by Partial Linearization: Parallel Optimization of
  Multi-Agent Systems

abstract:
  We propose a novel decomposition framework for the distributed optimization
of general nonconvex sum-utility functions arising naturally in the system
design of wireless multiuser interfering systems. Our main contributions are:
i) the development of the first class of (inexact) Jacobi best-response
algorithms with provable convergence, where all the users simultaneously and
iteratively solve a suitably convexified version of the original sum-utility
optimization problem; ii) the derivation of a general dynamic pricing mechanism
that provides a unified view of existing pricing schemes that are based,
instead, on heuristics; and iii) a framework that can be easily particularized
to well-known applications, giving rise to very efficient practical (Jacobi or
Gauss-Seidel) algorithms that outperform existing adhoc methods proposed for
very specific problems. Interestingly, our framework contains as special cases
well-known gradient algorithms for nonconvex sum-utility problems, and many
blockcoordinate descent schemes for convex functions.


title: Nanoplasmonic planar traps - a tool for engineering p-wave interactions

abstract:
  Engineering strong p-wave interactions between fermions is one of the
challenges in modern quantum physics. Such interactions are responsible for a
plethora of fascinating quantum phenomena such as topological quantum liquids
and exotic superconductors. In this letter we propose to combine recent
developments of nanoplasmonics with the progress in realizing laser-induced
gauge fields. Nanoplasmonics allows for strong confinement leading to a
geometric resonance in the atom-atom scattering. In combination with the
laser-coupling of the atomic states, this is shown to result in the desired
interaction. We illustrate how this scheme can be used for the stabilization of
strongly correlated fractional quantum Hall states in ultracold fermionic
gases.


title:
Interplay of IR-Improved DGLAP-CS Theory and NLO Parton Shower MC
  Precision

abstract:
  We present the interplay between the new IR-improved DGLAP-CS theory and the
precision of NLO parton shower/ME matched MC`s as it is realized by the new MC
Herwiri1.031 in interface to MC@NLO. We discuss phenomenological implications
using comparisons with recent LHC data on single heavy gauge boson production.


title:
A remark about polynomials with specified local minima and no other
  critical points

abstract:
  The following observation must surely be "well-known", but it seems worth
giving a simple and quite explicit proof. Take any finite subset X of Rn, n>1.
Then, there is a polynomial function P:Rn -> R which has local minima on the
set X, and has no other critical points. Applied to the negative gradient flow
of P, this implies that there is a polynomial vector field with asymptotically
stable equilibria on X and no other equilibria. Some trajectories of this
vector field are not pre-compact; a complementary observation says that, again
for arbitrary X, one can find a vector field with asymptotically stable
equilibria on X, no other equilibria except saddles, and all omega-limit sets
consisting of singletons.


title: Blowing up extremal K\"ahler manifolds II

abstract:
  This is a continuation of the work of Arezzo-Pacard-Singer and the author on
blowups of extremal K\"ahler manifolds. We prove the conjecture stated in [32],
and we relate this result to the K-stability of blown up manifolds. As an
application we prove that if a K\"ahler manifold M of dimension greater than 2
admits a cscK metric, then the blowup of M at a point admits a cscK metric if
and only if it is K-stable, as long as the exceptional divisor is sufficiently
small.


title: High Galactic latitude runaway stars as tracers of the spiral arms

abstract:
  A direct observation of the spiral structure of the Galaxy is hindered by our
position in the middle of the Galactic plane. We propose a method based on the
analysis of the birthplaces of high Galactic latitude runaway stars to map the
spiral arms and determine their dynamics. As a proof of concept, the method is
applied to a local sample of early-type stars and a sample of runaways stars to
obtain estimates of the pattern speed and the spiral arm's phase angle. We also
estimate the performance of this method once the data gathered by Gaia, in
particular for runaway stars observed on the other side of the Galaxy, is
available.


title: Formality and symplectic structures of almost abelian solvmanifolds

abstract:
  In this paper we study some properties of almost abelian solvmanifolds using
minimal models associated to a fibration. In particular we state a necessary
and sufficient condition to formality and a method for finding symplectic
strucures of this kind of solvmanifolds.


title: ALICE Physics Summary

abstract:
  The ALICE experiment at the LHC has collected data in proton-proton (pp)
collisions at $\sqrt{s}$ = 0.9, 2.76, 7 and 8 TeV, in lead-lead (Pb--Pb)
collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV and in proton-lead (p-Pb)
collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV. A summary overview of recent
experimental physics results obtained by ALICE is presented in this paper with
a selection of few representative measurements.


title: Gravity waves on the surface of topological superfluid 3He-B

abstract:
  We have observed waves on the free surface of 3He-B sample at temperatures
below 0.2mK. The waves are excited by vibrations of the cryostat and detected
by coupling the surface to the Bose-Einstein condensate of magnon
quasiparticles in the superfluid. The two lowest gravity-wave modes in our
cylindrical container are identified. Damping of the waves increases with
temperature linearly with the density of thermal quasiparticles, as expected.
Additionally finite damping of the waves in the zero-temperature limit and
enhancement of magnetic relaxation of magnon condensates by the surface waves
are observed. We discuss whether the latter effects may be related to Majorana
fermions bound to the surface of the topological superfluid.


title: Build your own analemma

abstract:
  Earth's analemma is the lopsided figure eight marked out over a year by the
position of the Sun in the sky observed at the same clock time each day. It
shows how solar time deviates from clock time. The analemma's shape results
from the tilt of Earth's axis of rotation relative to the plane of its orbit
around the Sun and from the elliptical shape of that orbit. This tutorial paper
uses vector analysis of the Earth-Sun geometry and a numerically generated
quantitative description of Earth's motion around the Sun to construct Earth's
analemma. To visualize the geometry and the motion that give rise to the
analemma is challenging, but this construction is a project within the
capability of physics students who have had basic undergraduate mechanics.


title: Flux and color variations of the doubly imaged quasar UM673

abstract:
  With the aim of characterizing the flux and color variations of the multiple
components of the gravitationally lensed quasar UM673 as a function of time, we
have performed multi-epoch and multi-band photometric observations with the
Danish 1.54m telescope at the La Silla Observatory.
  The observations were carried out in the VRi spectral bands during four
seasons (2008--2011). We reduced the data using the PSF (Point Spread Function)
photometric technique as well as aperture photometry.
  Our results show for the brightest lensed component some significant decrease
in flux between the first two seasons (+0.09/+0.11/+0.05 mag) and a subsequent
increase during the following ones (-0.11/-0.11/-0.10 mag) in the V/R/i
spectral bands, respectively. Comparing our results with previous studies, we
find smaller color variations between these seasons as compared with previous
ones. We also separate the contribution of the lensing galaxy from that of the
fainter and close lensed component.


title: 3.3 {\mu}m PAH observations of the central kiloparsecs of Centaurus A

abstract:
  Aims. The aim of this work is to further investigate the nature of PAH
excitation and emission especially in the context of tracing star formation in
a variety of extragalactic environments. Here we turn our attention to the
energetic environment of the closest AGN in our sample, Centaurus A. Methods.
Using ISAAC on the ESO VLT UT1 (Antu) we have made high spatial resolution 3.3
{\mu}m imaging observations of the central kiloparsec of CenA. These
observations have been compared with star formation tracers in the near- and
mid-infrared, as well as with mid-infrared tracers of nuclear activity.
Results. The nucleus is not devoid of PAH emission, implying that the PAH
particles are not destroyed in the nucleus as might be expected for such a
harsh environment. However, we see the feature to continuum ratio decrease
towards the AGN. As well, the 3.3 {\mu}m PAH feature emission generally traces
the sites of star formation in Cen A, but in detail there are spatial offsets,
consistent with an earlier study of the starburst galaxies NGC 253 and NGC
1808. However, the feature-to-continuum ratio does not drop at the positions of
star formation as was previously seen in that earlier study. The cause for this
difference remains uncertain. Finally, our data reveal possible evidence for a
nearly face-on, circular or spiral, dust structure surrounding the nucleus.


title:
The K-band luminosity functions of super star clusters in luminous
  infrared galaxies, their slopes, and the effects of blending

abstract:
  Super star clusters (SSCs) are typically found in interacting galaxies and
trace an extreme form of star-formation. We present a K-band study of SSC
candidates in a sample of local luminous infrared galaxies (LIRGs) using two
adaptive optics instruments (VLT/NACO and Gemini/ALTAIR/NIRI). In addition to
facilitating SSC detections in obscured environments, this work introduces SSC
studies in hosts with higher star-formation rates (SFRs) than most previous
studies. We find that the luminosity functions (LFs) of the clusters are
reasonably well-fitted by a single power-law with the values of the index
\alpha ranging between 1.5 to 2.4 with an average value of \alpha ~ 1.9. This
value appears to be less steep than the average \alpha ~ 2.2 in normal spiral
galaxies. Due to the host galaxy distances involved (median $D_L$ ~ 70 Mpc)
blending effects have to be taken into account, and are investigated using
Monte Carlo simulations of blending effects for LFs and a photometric SSC
analysis of the well-studied Antennae system which is artificially redshifted
to distances of our sample. While blending tends to flatten LFs our analyses
show that \Delta \alpha is less than ~ 0.1 in our sample. The simulations also
show that in the luminosity range, $M_K < -13$, considered in this work the
extracted SSC luminosities are generally dominated by a single dominant star
cluster rather than several knots of SF. We present resolution- and
distance-dependent SSC surface density confusion limits and show how blending
rates and aperture sizes affect the LFs. The smallest possible apertures should
be used in crowded regions.


title: Binomial regular sequences and free sums

abstract:
  Recently several authors have proved results on Ehrhart series of free sums
of rational polytopes. In this note we treat these results from an algebraic
viewpoint. Instead of attacking combinatorial statements directly, we derive
them from structural results on affine monoids and their algebras that allow
conclusions for Hilbert and Ehrhart series. We characterize when a binomial
regular sequence generates a prime ideal or even normality is preserved for the
residue class ring.


title: Graphene-based plasmonic switches at near infrared frequencies

abstract:
  The concept, analysis, and design of series switches for graphene-strip
plasmonic waveguides at near infrared frequencies are presented. Switching is
achieved by using graphene's field effect to selectively enable or forbid
propagation on a section of the graphene strip waveguide, thereby allowing good
transmission or high isolation, respectively. The electromagnetic modeling of
the proposed structure is performed using full-wave simulations and a
transmission line model combined with a matrix-transfer approach, which takes
into account the characteristics of the plasmons supported by the different
graphene-strip waveguide sections of the device. The performance of the switch
is evaluated versus different parameters of the structure, including
surrounding dielectric media, electrostatic gating and waveguide dimensions.


title: Observation, Characterization and Modeling of Memristor Current Spikes

abstract:
  Memristors have been compared to neurons (usually specifically the synapses)
since 1976 but no experimental evidence has been offered for support for this
position. Here we highlight that memristors naturally form fast-response,
highly reproducible and repeatable current spikes which can be used in
voltage-driven neuromorphic architecture. Ease of fitting current spikes with
memristor theories both suggests that the spikes are part of the memristive
effect and provides modeling capability for the design of neuromorphic
circuits.


title: Primes In Cubic Arithmetic Progressions

abstract:
  This work proposes a proof of the simplest cubic primes counting problem. It
shows that the subset of primes {p = n^3 + 2 is prime : n => 1} is an infinite
subset of primes. Further, the expected order of magnitude of the cubic primes
counting function is established.


title:
Taste-split staggered actions: eigenvalues, chiralities and Symanzik
  improvement

abstract:
  The eigenvalue spectra of staggered fermions with an Adams and/or Hoelbling
mass term are studied. The chiralities of the eigenmodes reflect whether the
chirality linked to the unflavored approximate (\gamma_5 \times 1) or the
flavored exact (\gamma_5 \times \xi_5) staggered symmetry is considered, and
which one of the RR, LR, RL, LL eigenmode definitions is used. In either case a
sensitivity to the topological charge of the gauge background is found. We
discuss how to remove the leading cut-off effects of these actions by means of
a properly tuned improvement term and/or the overlap procedure. The combination
of Symanzik improvement and link smearing radically improves the properties of
the physical branch.


title:
Scaling limits of spatial compartment models for chemical reaction
  networks

abstract:
  We study the effects of fast spatial movement of molecules on the dynamics of
chemical species in a spatially heterogeneous chemical reaction network using a
compartment model. The reaction networks we consider are either single- or
multi-scale. When reaction dynamics is on a single-scale, fast spatial movement
has a simple effect of averaging reactions over the distribution of all the
species. When reaction dynamics is on multiple scales, we show that spatial
movement of molecules has different effects depending on whether the movement
of each type of species is faster or slower than the effective reaction
dynamics on this molecular type. We obtain results for both when the system is
without and with conserved quantities, which are linear combinations of species
evolving only on the slower time scale.


title: Parimagnetism in RCo$_2$ series (R=Dy, Ho, and Tm)

abstract:
  X-ray circular magnetic dichroism (XMCD), longitudinal ($\chi_{ac}$) and
transverse (TS) ac magnetic susceptibility have been measured in several
members of the $R$Co$_2$ series ($R$ = Dy, Ho, and Tm) as a function of
temperature and applied magnetic field. We show that parimagnetism is a general
behavior along the $R$Co$_2$ ferrimagnetic series ($R$ being a heavy rare earth
ion). XMCD results evidence the presence of two compensation temperatures,
defining two different parimagnetic configurations, which is a fully unexpected
result. The inverse $\chi_{ac}$ curve exhibits a deviation from Curie-Weiss
behavior which is recovered under applied magnetic field. The large excess of
polarizability above the critical temperature proves the existence of an
enhanced effective moment due to the presence of short range magnetic
correlations, which are also observed in TS measurements. The combination of TS
and XMCD measurements allows to depict new magnetic phase diagrams for the
$R$Co$_2$ series. A new scenario allowing to understand the observed
phenomenology as a Griffiths phase-like behavior is proposed, where the
amorphous $R$Co$_2$ represents the undiluted system case.


title: Extremal Sasakian Geometry on S^3-bundles over Riemann Surfaces

abstract:
  In this paper we study the Sasakian geometry on S^3-bundles over a Riemann
surface of genus g>0 with emphasis on extremal Sasaki metrics. We prove the
existence of a countably infinite number of inequivalent contact structures on
the total space of such bundles that admit 2-dimensional Sasaki cones each with
a Sasaki metric of constant scalar curvature (CSC). This CSC Sasaki metric is
most often irregular. We further study the extremal subset in the Sasaki cone
showing that if 0<g<5 it exhausts the entire cone. Examples are given where
exhaustion fails.


title: Bulging deformations of convex $RP^2$-manifolds

abstract: We define deformations of $RP^2$-manifolds.


title: On graphic lambda calculus and the dual of the graphic beta move

abstract:
  This is a short description of graphic lambda calculus, with special emphasis
on a duality suggested by the two different appearances of knot diagrams, in
lambda calculus and emergent algebra sectors of the graphic lambda calculus
respectively. This duality leads to the introduction of the dual of the graphic
beta move. While the graphic beta move corresponds to beta reduction in untyped
lambda calculus, the dual graphic beta move appears in relation to emergent
algebras.


title: Long baseline neutrino experiments, mass hierarchy and delta(CP)

abstract:
  We investigate the possibilities offered by the long baseline experiments
T2K, No$\nu$a, LBNE and LAGUNA for the evaluation of the neutrino mass
hierarchy and CP violating phase $\delta_{CP}$. We consider a neutrino and
antineutrino energy in the interval [0.5,12] GeV. It is found that the clearest
possible distinction between the two hierarchy signatures is provided by LAGUNA
for an (anti)neutrino energy $E_{(\bar\nu)\nu}\simeq 0.5$ GeV in the
$(\bar\nu_{\mu} \rightarrow \bar\nu_{\mu}) \nu_{\mu}\rightarrow \nu_{\mu}$
disappearance channel. For LBNE at $E_{\bar\nu}\simeq 1$ GeV the
$\bar\nu_{\mu}\rightarrow \bar\nu_{\mu}$ channel may also provide a
distinction, although not so clear, and for No$\nu$a this may be even less
clear. These results are essentially the same for the $\theta_{23}$ first and
second octant solutions. As for $\delta_{CP}$ determination, LAGUNA also offers
the best chances at $E_{\bar\nu}\simeq 0.5$ GeV in the
$\bar\nu_{\mu}\rightarrow \bar\nu_{e}$ channel with $\theta_{23}$ in either
octant. Regarding nonstandard interactions, the best possibility for their
investigation resides in No$\nu$a whose source-far detector distance can become
a magic baseline if the hierarchy is normal for channels $\nu_{\mu}\rightarrow
\nu_{\mu}$, $\bar\nu_{\mu}\rightarrow \bar\nu_{e}$, $\bar\nu_{\mu}\rightarrow
\bar\nu_{\mu}$ with energy (8.9-9.1) GeV, (11.6-12) GeV, (8.8-12) GeV. If the
hierarchy is inverse, magic baselines for No$\nu$a occur for
$\nu_{\mu}\rightarrow \nu_{e}$, $\nu_{\mu}\rightarrow \nu_{\mu}$, and
$\bar\nu_{\mu}\rightarrow \bar\nu_{\mu}$ with energy (11.8-12) GeV, (8.9-12.3)
GeV, (8.8-8.9) GeV. For LAGUNA a magic baseline appears for the
$\bar\nu_{\mu}\rightarrow \bar\nu_{\mu}$ channel only at (4.7-5.0) GeV in
inverse hierarchy. We have also investigated a possible complementarity between
T2K and No$\nu$a.


title: Internal models for nonlinear output agreement and optimal flow control

abstract:
  This paper studies the problem of output agreement in networks of nonlinear
dynamical systems under time-varying disturbances. Necessary and sufficient
conditions for output agreement are derived for the class of incrementally
passive systems. Following this, it is shown that the optimal distribution
problem in dynamic inventory systems with time-varying supply and demand can be
cast as a special version of the output agreement problem. We show in
particular that the time-varying optimal distribution problem can be solved by
applying an internal model controller to the dual variables of a certain convex
network optimization problem.


title:
Floquet topological quantum phase transitions in the transverse
  Wen-plaquette model

abstract:
  Our aim in this work is to study the nonequilibrium behavior of the
topological quantum phase transition in the transverse Wen-plaquette model. We
show that under the effect of a nonadiabatic driving the system exhibits a new
topological phase and a rich phase diagram. We define generalized topological
order parameters by considering cycle-averaged expectation values of string
operators in a Floquet state


title:
Decoupling Crossover in Asymmetric Broadside Coupled Split Ring
  Resonators at Terahertz Frequencies

abstract:
  We investigate the electromagnetic response of asymmetric broadside coupled
split ring resonators (ABC-SRRs) as a function of the relative in-plane
displacement between the two component SRRs. The asymmetry is defined as the
difference in the capacitive gap widths (\Delta g) between the two resonators
comprising a coupled unit. We characterize the response of ABC-SRRs both
numerically and experimentally via terahertz time-domain spectroscopy. As with
symmetric BC-SRRs (\Delta g=0 \mu m), a large redshift in the LC resonance is
observed with increasing displacement, resulting from changes in the capacitive
and inductive coupling. However, for ABC-SRRs, in-plane shifting between the
two resonators by more than 0.375Lo (Lo=SRR sidelength) results in a transition
to a response with two resonant modes, associated with decoupling in the
ABC-SRRs. For increasing \Delta g, the decoupling transition begins at the same
relative shift (0.375Lo), though with an increase in the oscillator strength of
the new mode. This strongly contrasts with symmetric BC-SRRs which present only
one resonance for shifts up to 0.75Lo. Since all BC-SRRs are effectively
asymmetric when placed on a substrate, an understanding of ABC-SRR behavior is
essential for a complete understanding of BC-SRR based metamaterials.


title:
An Estimate of Lambda in Resummed Quantum Gravity in the Context of
  Asymptotic Safety and Planck Scale Cosmology: Constraints on SUSY GUTS

abstract:
  We use the amplitude-based resummation of Feynman`s formulation of Einstein`s
theory to arrive at a UV finite approach to quantum gravity. We show that we
recover the UV fixed point recently claimed by the exact field-space
renormalization group approach. We use our approach in the context of the
attendant Planck scale cosmology formulation of Bonanno and Reuter to estimate
the value of the cosmological constant as \rho_\Lambda=(0.0024 eV)^4. We show
that the closeness of this estimate to experiment constrains susy GUT models.


title:
Information Measures for Long-Range Correlated Sequences: the Case of
  the 24 Human Chromosome Sequences

abstract:
  A new approach to estimate the Shannon entropy of a long-range correlated
sequence is proposed. The entropy is written as the sum of two terms
corresponding respectively to power-law (\emph{ordered}) and exponentially
(\emph{disordered}) distributed blocks (clusters). The approach is illustrated
on the 24 human chromosome sequences by taking the nucleotide composition as
the relevant information to be encoded/decoded. Interestingly, the nucleotide
composition of the \emph{ordered} clusters is found, on the average, comparable
to the one of the whole analyzed sequence, while that of the \emph{disordered}
clusters fluctuates. From the information theory standpoint, this means that
the power-law correlated clusters carry the same information of the whole
analysed sequence. Furthermore, the fluctuations of the nucleotide composition
of the disordered clusters are linked to relevant biological properties, such
as segmental duplications and gene density.


title:
Beyond Markov Chains, Towards Adaptive Memristor Network-based Music
  Generation

abstract:
  We undertook a study of the use of a memristor network for music generation,
making use of the memristor's memory to go beyond the Markov hypothesis. Seed
transition matrices are created and populated using memristor equations, and
which are shown to generate musical melodies and change in style over time as a
result of feedback into the transition matrix. The spiking properties of simple
memristor networks are demonstrated and discussed with reference to
applications of music making. The limitations of simulating composing memristor
networks in von Neumann hardware is discussed and a hardware solution based on
physical memristor properties is presented.


title:
NbTiN superconducting nanowire detectors for visible and telecom
  wavelengths single photon counting on Si3N4 photonic circuits

abstract:
  We demonstrate niobium titanium nitride superconducting nanowires patterned
on stoichiometric silicon nitride waveguides for detecting visible and infrared
photons. The use of silicon nitride on insulator on silicon substrates allows
us to simultaneously realize photonic circuits for visible and infrared light
and integrate them with nanowire detectors directly on-chip. By implementing a
traveling wave detector geometry in this material platform, we achieve
efficient single photon detection for both wavelength regimes. Our detectors
are an ideal match for integrated quantum optics as they provide crucial
functionality on a wideband transparent waveguide material.


title: Evolution of unknotting strategies for knots and braids

abstract:
  This paper explores the problem of unknotting closed braids and classical
knots in mathematical knot theory. We apply evolutionary computation methods to
learn sequences of moves that simplify knot diagrams, and show that this can be
effective both when the evolution is carried out for individual knots and when
a generic sequence of moves is evolved for a set of knots.


title:
Absorption Efficiencies of Forsterite. I: DDA Explorations in Grain
  Shape and Size

abstract:
  We compute the absorption efficiency (Qabs) of forsterite using the discrete
dipole approximation (DDA) in order to identify and describe what
characteristics of crystal grain shape and size are important to the shape,
peak location, and relative strength of spectral features in the 8-40 {\mu}m
wavelength range. Using the DDSCAT code, we compute Qabs for non-spherical
polyhedral grain shapes with a_eff = 0.1 {\mu}m. The shape characteristics
identified are: 1) elongation/reduction along one of three crystallographic
axes; 2) asymmetry, such that all three crystallographic axes are of different
lengths; and 3) the presence of crystalline faces that are not parallel to a
specific crystallographic axis, e.g., non-rectangular prisms and (di)pyramids.
Elongation/reduction dominates the locations and shapes of spectral features
near 10, 11, 16, 23.5, 27, and 33.5 {\mu}m, while asymmetry and tips are
secondary shape effects. Increasing grain sizes (0.1-1.0 {\mu}m) shifts the 10,
11 {\mu}m features systematically towards longer wavelengths and relative to
the 11 {\mu}m feature increases the strengths and slightly broadens the longer
wavelength features. Seven spectral shape classes are established for
crystallographic a-, b-, and c-axes and include columnar and platelet shapes
plus non-elongated or equant grain shapes. The spectral shape classes and the
effects of grain size have practical application in identifying or excluding
columnar, platelet or equant forsterite grain shapes in astrophysical environs.
Identification of the shape characteristics of forsterite from 8-40 {\mu}m
spectra provides a potential means to probe the temperatures at which
forsterite formed.


title: Boundary behavior of the Kobayashi metric near a point of infinite type

abstract:
  Under a potential-theoretical hypothesis named $f$-Property with $f$
satisfying $\displaystyle\int_t^\infty \dfrac{da}{a f(a)}<\infty$, we show that
the Kobayashi metric $K(z,X)$ on a weakly pseudoconvex domain $\Om$, satisfies
the estimate $K(z,X)\ge Cg(\delta_\Om(x)^{-1})|X|$ for any $X\in T^{1,0}\Om$
where $(g(t))^{-1}$ denotes the above integral and $\delta_\Om(z)$ is the
distance from $z$ to $b\Om$.


title:
Time--distance inversions for horizontal and vertical flows on
  supergranular scales applied to MDI and HMI data

abstract:
  We study the possibility of consistent extension of MDI full-disc
helioseismic campaigns with the growing data set of HMI observations. To do so,
we down-sample and filter the HMI Dopplegrams so that the resulting spatial
power spectrum is similar to the spatial power spectrum of MDI full-disc
Dopplergrams. The set of co-spatial and co-temporal datacube pairs from both
instruments containing no missing and no bad frames were processed using the
same codes and inverted independently for all three components of the plasma
flow in the near surface layers. The results from the two instruments are
highly correlated, however systematically larger (by ~20%) flow magnitudes are
derived from HMI. We comment that this may be an effect of the different
formation depth of the Doppler signal


title:
Lower bound for the geometric type from a generalized estimate in the
  $\dib$-Neumann problem - a new approach by peak functions

abstract:
  We give a simple proof of the fact that an "$f$-estimate" for the
$\bar\partial$-Neumann problem implies a lower bound on the geomatric type of
the boundary along any complex one dimensional variety. The proof uses the
existence of peak functions which is in turn a consequence of the $f$-estimate.


title: Probe Scheduling for Efficient Detection of Silent Failures

abstract:
  Most discovery systems for silent failures work in two phases: a continuous
monitoring phase that detects presence of failures through probe packets and a
localization phase that pinpoints the faulty element(s). This separation is
important because localization requires significantly more resources than
detection and should be initiated only when a fault is present.
  We focus on improving the efficiency of the detection phase, where the goal
is to balance the overhead with the cost associated with longer failure
detection times. We formulate a general model which unifies the treatment of
probe scheduling mechanisms, stochastic or deterministic, and different cost
objectives - minimizing average detection time (SUM) or worst-case detection
time (MAX).
  We then focus on two classes of schedules. {\em Memoryless schedules} -- a
subclass of stochastic schedules which is simple and suitable for distributed
deployment. We show that the optimal memorlyess schedulers can be efficiently
computed by convex programs (for SUM objectives) or linear programs (for MAX
objectives), and surprisingly perhaps, are guaranteed to have expected
detection times that are not too far off the (NP hard) stochastic optima. {\em
Deterministic schedules} allow us to bound the maximum (rather than expected)
cost of undetected faults, but like stochastic schedules, are NP hard to
optimize. We develop novel efficient deterministic schedulers with provable
approximation ratios.
  An extensive simulation study on real networks, demonstrates significant
performance gains of our memoryless and deterministic schedulers over previous
approaches. Our unified treatment also facilitates a clear comparison between
different objectives and scheduling mechanisms.


title:
A First-Passage Kinetic Monte Carlo Method for Reaction-Drift-Diffusion
  Processes

abstract:
  Stochastic reaction-diffusion models are now a popular tool for studying
physical systems in which both the explicit diffusion of molecules and noise in
the chemical reaction process play important roles. The Smoluchowski
diffusion-limited reaction model (SDLR) is one of several that have been used
to study biological systems. Exact realizations of the underlying stochastic
process described by the SDLR model can be generated by the recently proposed
First-Passage Kinetic Monte Carlo (FPKMC) method. This exactness relies on
sampling analytical solutions to one and two-body diffusion equations in
simplified protective domains.
  In this work we extend the FPKMC to allow for drift arising from fixed,
background potentials. As the corresponding Fokker-Planck equations that
describe the motion of each molecule can no longer be solved analytically, we
develop a hybrid method that discretizes the protective domains. The
discretization is chosen so that the drift-diffusion of each molecule within
its protective domain is approximated by a continuous-time random walk on a
lattice. New lattices are defined dynamically as the protective domains are
updated, hence we will refer to our method as Dynamic Lattice FPKMC or
DL-FPKMC. We focus primarily on the one-dimensional case in this manuscript,
and demonstrate the numerical convergence and accuracy of our method in this
case for both smooth and discontinuous potentials. We also present applications
of our method, which illustrate the impact of drift on reaction kinetics.


title: Linear sequences and weighted ergodic theorems

abstract:
  We present a simple way to produce good weights for several types of ergodic
theorem including the Wiener-Wintner type multiple return time theorem and the
multiple polynomial ergodic theorem. These weights are deterministic and come
from orbits of certain bounded linear operators on Banach spaces. This extends
the known results for nilsequences and return time sequences of the form
(g(S^ny)) for a measure preserving system (Y,S) and g\in L^\infty(Y), avoiding
in the latter case the problem of finding the full measure set of appropriate
points y.


title: On the gauge features of gravity on a Lie algebroid structure

abstract:
  We present the geometric formulation of gravity based on the mathematical
structure of a Lie Algebroid. We show that this framework provides the
geometrical setting to describe the gauge propriety of gravity.


title:
Quenching and Channeling of Nuclear Recoils in NaI[Tl]: Implications for
  Dark Matter Searches

abstract:
  A new experimental evaluation of the quenching factor for nuclear recoils in
NaI[Tl] is described. Systematics affecting previous measurements are addressed
by careful characterization of the emission spectrum of the neutron source, use
of a small scintillator coupled to an ultra-bialkali high quantum efficiency
photomultiplier, and evaluation of non-linearities in the electron recoil
response via Compton scattering. A trend towards a rapidly diminishing
quenching factor with decreasing sodium recoil energy is revealed.
Additionally, no evidence for crystal lattice channeling of low-energy
recoiling ions is found in a scintillator of known crystallographic
orientation. A discussion on how these findings affect dark matter searches
employing NaI[Tl] (e.g., DAMA/LIBRA) is offered.

categories: physics.ins-det astro-ph.CO hep-ex hep-ph


title:
Comparison of Ant-Inspired Gatherer Allocation Approaches using
  Memristor-Based Environmental Models

abstract:
  Memristors are used to compare three gathering techniques in an
already-mapped environment where resource locations are known. The All Site
model, which apportions gatherers based on the modeled memristance of that
path, proves to be good at increasing overall efficiency and decreasing time to
fully deplete an environment, however it only works well when the resources are
of similar quality. The Leaf Cutter method, based on Leaf Cutter Ant behaviour,
assigns all gatherers first to the best resource, and once depleted, uses the
All Site model to spread them out amongst the rest. The Leaf Cutter model is
better at increasing resource influx in the short-term and vastly out-performs
the All Site model in a more varied environments. It is demonstrated that
memristor based abstractions of gatherer models provide potential methods for
both the comparison and implementation of agent controls.


title: The Coulomb problem on a 3-sphere and Heun polynomials

abstract:
  The paper studies the quantum mechanical Coulomb problem on a 3-sphere. We
present a special parametrization of the ellipto-spheroidal coordinate system
suitable for the separation of variables. After quantization we get the
explicit form of the spectrum and present an algebraic equation for the
eigenvalues of the Runge-Lentz vector. We also present the wave functions
expressed via Heun polynomials.


title: On the Instanton R-matrix

abstract:
  A torus action on a symplectic variety allows one to construct solutions to
the quantum Yang-Baxter equations (R-matrices). For a torus action on cotangent
bundles over flag varieties the resulting R-matrices are the standard rational
solutions of the Yang-Baxter equation, which are well known in the theory of
quantum integrable systems. The torus action on the instanton moduli space
leads to more complicated R-matrices, depending additionally on two equivariant
parameters t_1 and t_2. In this paper we derive an explicit expression for the
R-matrix associated with the instanton moduli space. We study its matrix
elements and its Taylor expansion in the powers of the spectral parameter.
Certain matrix elements of this R-matrix give a generating function for the
characteristic classes of tautological bundles over the Hilbert schemes in
terms of the bosonic cut-and-join operators. In particular we rederive from the
R-matrix the well known Lehn's formula for the first Chern class. We explicitly
compute the first several coefficients for the power series expansion of the
R-matrix in the spectral parameter. These coefficients are represented by
simple contour integrals of some symmetrized bosonic fields.


title: Geometric Boundary Data for the Gravitational Field

abstract:
  An outstanding issue in the treatment of boundaries in general relativity is
the lack of a local geometric interpretation of the necessary boundary data.
For the Cauchy problem, the initial data is supplied by the 3-metric and
extrinsic curvature of the initial Cauchy hypersurface.. This Cauchy data
determines a solution to Einstein's equations which is unique up to a
diffeomorphism. Here, we show how three pieces of boundary data, which are
associated locally with the geometry of the boundary, likewise determine a
solution of the initial-boundary value problem which is unique up to a
diffeomorphism. One piece of this data, constructed from the extrinsic
curvature of the boundary, determines the dynamical evolution of the boundary.
The other two pieces constitute a conformal class of rank-2, positive definite
metrics, which represent the two gravitational degrees of freedom.


title:
Subsingular vectors in Verma modules, and tensor product modules over
  the twisted Heisenberg-Virasoro algebra and W(2,2) algebra

abstract:
  We show that subsingular vectors exist in Verma modules over W(2,2), and
present a subquotient structure of these modules. We prove conditions for
irreducibility of a tensor product of intermediate series module with the
highest weight module. Relations to intertwining operators over vertex operator
algebra associated to W(2,2) is discussed. Also, we study a tensor product of
intermediate series and highest weight module over the twisted
Heisenberg-Virasoro algebra, and present series of irreducible modules with
infinite-dimensional weight spaces.


title: DBI equations and holographic DC conductivity

abstract:
  We provide a simple method for writing the Dirac-Born-Infeld (DBI) equations
of a Dp-brane in an arbitrary static background whose metric depends only on
the holographic radial coordinate z. Using this method we revisit the
Karch-O'Bannon's procedure to calculate the DC conductivity in the presence of
constant electric and magnetic fields for backgrounds where the boundary is
four or three dimensional and satisfies homogeneity and isotropy. We find a
frame-independent expression for the DC conductivity tensor. For particular
backgrounds we recover previous results on holographic metals and strange
metals.


title: The Mori Program and Non-Fano Toric Homological Mirror Symmetry

abstract:
  In the case of toric varieties, we continue the pursuit of Kontsevich's
fundamental insight, Homological Mirror Symmetry, by unifying it with the Mori
program. We give a refined conjectural version of Homological Mirror Symmetry
relating semi-orthogonal decompositions of the $B$-model on toric varieties to
semi-orthogonal decompositions on the $A$-model on the mirror Landau-Ginzburg
models.
  As evidence, we prove a new case of Homological Mirror Symmetry for a toric
surface whose anticanonical bundle is not nef, namely a certain blow-up of
$\P^2$ at three infinitesimally near points.


title: Simplicial Ricci Flow

abstract:
  We construct a discrete form of Hamilton's Ricci flow (RF) equations for a
d-dimensional piecewise flat simplicial geometry, S. These new algebraic
equations are derived using the discrete formulation of Einstein's theory of
general relativity known as Regge calculus. A Regge-Ricci flow (RRF) equation
is naturally associated to each edge, L, of a simplicial lattice. In defining
this equation, we find it convenient to utilize both the simplicial lattice, S,
and its circumcentric dual lattice, S*. In particular, the RRF equation
associated to L is naturally defined on a d-dimensional hybrid block connecting
$\ell$ with its (d-1)-dimensional circumcentric dual cell, L*. We show that
this equation is expressed as the proportionality between (1) the simplicial
Ricci tensor, Rc_L, associated with the edge L in S, and (2) a certain volume
weighted average of the fractional rate of change of the edges, lambda in L*,
of the circumcentric dual lattice, S*, that are in the dual of L. The inherent
orthogonality between elements of S and their duals in S* provide a simple
geometric representation of Hamilton's RF equations. In this paper we utilize
the well established theories of Regge calculus, or equivalently discrete
exterior calculus, to construct these equations. We solve these equations for a
few illustrative examples.


title:
Nonlinear normal modes of a two degree of freedom oscillator with a
  bilateral elastic stop

abstract:
  A study of the non linear modes of a two degree of freedom mechanical system
with bilateral elastic stop is considered. The issue related to the
non-smoothness of the impact force is handled through a regularization
technique. In order to obtain the Nonlinear Normal Mode (NNM), the harmonic
balance method with a large number of harmonics, combined with the asymptotic
numerical method, is used to solve the regularized problem. These methods are
present in the software "package" MANLAB. The results are validated from
periodic orbits obtained analytically in the time domain by direct integration
of the non regular problem. The two NNMs starting respectively from the two
linear normal modes of the associated underlying linear system are discussed.
The energy-frequency plot is used to present a global vision of the behavior of
the modes. The dynamics of the modes are also analyzed comparing each periodic
orbits and modal lines. The first NNM shows an elaborate dynamics with the
occurrence of multiple impacts per period. On the other hand, the second NNM
presents a more simple dynamics with a localization of the displacement on the
first mass.


title:
On the Fundamental Feedback-vs-Performance Tradeoff over the MISO-BC
  with Imperfect and Delayed CSIT

abstract:
  This work considers the multiuser multiple-input single-output (MISO)
broadcast channel (BC), where a transmitter with M antennas transmits
information to K single-antenna users, and where - as expected - the quality
and timeliness of channel state information at the transmitter (CSIT) is
imperfect. Motivated by the fundamental question of how much feedback is
necessary to achieve a certain performance, this work seeks to establish bounds
on the tradeoff between degrees-of-freedom (DoF) performance and CSIT feedback
quality. Specifically, this work provides a novel DoF region outer bound for
the general K-user MISO BC with partial current CSIT, which naturally bridges
the gap between the case of having no current CSIT (only delayed CSIT, or no
CSIT) and the case with full CSIT. The work then characterizes the minimum CSIT
feedback that is necessary for any point of the sum DoF, which is optimal for
the case with M >= K, and the case with M=2, K=3.


title:
Non-compactness of the Neumann operator for the Kohn Laplacian on the
  Heisenberg ball

abstract:
  For $1\leq q \leq n-2$, we provide explicit examples to demonstrate
non-compactness of the Neumann operator for the Kohn Laplacian acting on $L^2$
$(0,q)$-forms on the unit ball in $(2n+1)$-dimensional Heisenberg space.


title: Slow dynamics of the contact process on complex networks

abstract:
  The Contact Process has been studied on complex networks exhibiting different
kinds of quenched disorder. Numerical evidence is found for Griffiths phases
and other rare region effects, in Erd\H os R\'enyi networks, leading rather
generically to anomalously slow (algebraic, logarithmic,...) relaxation. More
surprisingly, it turns out that Griffiths phases can also emerge in the absence
of quenched disorder, as a consequence of sole topological heterogeneity in
networks with finite topological dimension. In case of scale-free networks,
exhibiting infinite topological dimension, slow dynamics can be observed on
tree-like structures and a superimposed weight pattern. In the infinite size
limit the correlated subspaces of vertices seem to cause a smeared phase
transition. These results have a broad spectrum of implications for propagation
phenomena and other dynamical process on networks and are relevant for the
analysis of both models and empirical data.


title:
Sample paths properties of Gaussian fields with equivalent spectral
  densities

abstract:
  We prove that if $X$ and $Y$ are two Gaussian fields with equivalent spectral
densities, they have the same sample paths properties in any separable Banach
space continuously embedded in $\mathcal{C}^0(K)$ where $K$ is a compact set of
$\mathbb{R}^d$.


title: Distribution of postcritically finite polynomials

abstract:
  We prove that Misiurewicz parameters with prescribed combinatorics and
hyperbolic parameters with (d - 1) distinct attracting cycles with given
multipliers are equidistributed with respect to the bifurcation measure in the
moduli space of degree d complex polynomials. Our proof relies on Yuan's
equidistribution results of points of small heights, and uses in a crucial way
Epstein's transversality results.


title:
Semiclassical measure for the solution of the Helmholtz equation with an
  unbounded source

abstract:
  We study the high frequency limit for the dissipative Helmholtz equation when
the source term concentrates on a submanifold of R^n. We prove that the
solution has a unique semi-classical measure, which is precisely described in
terms of the classical properties of the problem. This result is already known
when the micro-support of the source is bounded, we now consider the general
case.


title: Excluding Pairs of Graphs

abstract:
  For a graph $G$ and a set of graphs $\mathcal{H}$, we say that $G$ is {\em
$\mathcal{H}$-free} if no induced subgraph of $G$ is isomorphic to a member of
$\mathcal{H}$. Given an integer $P>0$, a graph $G$, and a set of graphs
$\mathcal{F}$, we say that $G$ {\em admits an $(\mathcal{F},P)$-partition} if
the vertex set of $G$ can be partitioned into $P$ subsets $X_1,..., X_P$, so
that for every $i \in \{1,..., P\}$, either $|X_i|=1$, or the subgraph of $G$
induced by $X_i$ is $\{F\}$-free for some $F \in \mathcal{F}$.
  Our first result is the following. For every pair $(H,J)$ of graphs such that
$H$ is the disjoint union of two graphs $H_1$ and $H_2$, and the complement
$J^c$ of $J$ is the disjoint union of two graphs $J_1^c$ and $J_2^c$, there
exists an integer $P>0$ such that every $\{H,J\}$-free graph has an
$(\{H_1,H_2,J_1,J_2\},P)$-partition. Using a similar idea we also give a short
proof of one of the results of \cite{heroes}.
  Our final result is a construction showing that if $\{H,J\}$ are graphs each
with at least one edge, then for every pair of integers $r,k$ there exists a
graph $G$ such that every $r$-vertex induced subgraph of $G$ is
$\{H,J\}$-split, but $G$ does not admits an $(\{H,J\},k)$-partition.


title: Energy Estimates for Low Regularity Bilinear Schr\"odinger Equations

abstract:
  This paper presents an energy estimate in terms of the total variation of the
control for bilinear infinite dimensional quantum systems with unbounded
potentials. These estimates allow a rigorous construction of propagators
associated with controls of bounded variation. Moreover, upper bounds of the
error made when replacing the infinite dimensional system by its finite
dimensional Galerkin approximations is presented.


title: Nonlinear flows and rigidity results on compact manifolds

abstract:
  This paper is devoted to rigidity results for some elliptic PDEs and related
interpolation inequalities of Sobolev type on smooth compact connected
Riemannian manifolds without boundaries. Rigidity means that the PDE has no
other solution than the constant one at least when a parameter is in a certain
range. This parameter can be used as an estimate for the best constant in the
corresponding interpolation inequality. Our approach relies in a nonlinear flow
of porous medium / fast diffusion type which gives a clear-cut interpretation
of technical choices of exponents done in earlier works. We also establish two
integral criteria for rigidity that improve upon known, pointwise conditions,
and hold for general manifolds without positivity conditions on the curvature.
Using the flow, we are also able to discuss the optimality of the corresponding
constant in the interpolation inequalities.


title: Which notion of energy for bilinear quantum systems?

abstract:
  In this note we investigate what is the best L^p-norm in order to describe
the relation between the evolution of the state of a bilinear quantum system
with the L^p-norm of the external field. Although L^2 has a structure more easy
to handle, the L^1 norm is more suitable for this purpose. Indeed for every
p>1, it is possible to steer, with arbitrary precision, a generic bilinear
quantum system from any eigenstate of the free Hamiltonian to any other with a
control of arbitrary small L^p norm. Explicit optimal costs for the L^1 norm
are computed on an example.


title: Thermodynamics of Higher Spin Black Holes in AdS$_3$

abstract:
  We discuss the thermodynamics of recently constructed three-dimensional
higher spin black holes in SL(N,R)\times SL(N,R) Chern-Simons theory with
generalized asymptotically-anti-de Sitter boundary conditions. From a
holographic perspective, these bulk theories are dual to two-dimensional CFTs
with W_N symmetry algebras, and the black hole solutions are dual to thermal
states with higher spin chemical potentials and charges turned on. Because the
notion of horizon area is not gauge-invariant in the higher spin theory, the
traditional approaches to the computation of black hole entropy must be
reconsidered. One possibility, explored in the recent literature, involves
demanding the existence of a partition function in the CFT, and consistency
with the first law of thermodynamics. This approach is not free from
ambiguities, however, and in particular different definitions of energy result
in different expressions for the entropy. In the present work we show that
there are natural definitions of the thermodynamically conjugate variables that
follow from careful examination of the variational principle, and moreover
agree with those obtained via canonical methods. Building on this intuition, we
derive general expressions for the higher spin black hole entropy and free
energy which are written entirely in terms of the Chern-Simons connections, and
are valid for both static and rotating solutions. We compare our results to
other proposals in the literature, and provide a new and efficient way to
determine the generalization of the Cardy formula to a situation with higher
spin charges.


title:
A statistical testing framework for evaluating the quality of
  measurement processes

abstract:
  In this paper in which we address the evaluation of measurement process
quality, we mainly focus on the evaluation procedure, as far as it is based on
the numerical measurement outcomes. We challenge the approach where the "exact"
value of the observed quantity is compared to the error interval obtained from
the measurements under test and we propose a procedure where reference
measurements are used as "gold standard". To this purpose, we designed a
specific t-test procedure for this purpose, explained here. We also describe
and discuss a numerical simulation experiment demonstrating the behaviour of
our procedure.


title:
An optimality result about sample path properties of Operator Scaling
  Gaussian Random Fields

abstract:
  We study the sample paths properties of Operator scaling Gaussian random
fields. Such fields are anisotropic generalizations of anisotropic self-similar
random fields as anisotropic Fractional Brownian Motion. Some characteristic
properties of the anisotropy are revealed by the regularity of the sample
paths. The sharpest way of measuring smoothness is related to these
anisotropies and thus to the geometry of these fields.


title: A strong optimality result for anisotropic self--similar textures

abstract:
  In previous works, we proposed a method to characterize jointly
self-similarity and anisotropy properties of a large class of self--similar
Gaussian random fields. We provide here a mathematical analysis of our
approach, proving that the sharpest way of measuring smoothness is related to
these anisotropies and thus to the geometry of these fields.


title: Wheel of B2C E-commerce Development in Saudi Arabia

abstract:
  Online retailing (a model of B2C e-commerce) is growing world-wide, with
companies in many countries showing increased sales and productivity as a
result. It has great potential within the global economy. This paper looks at
the current status of online retailing in Saudi Arabia, with particular focus
on what inhibits or enables both the customers and retailers. It also analyses
the status of Government involvement and proposes a layered model, known as the
Wheel of Online Retailing which illustrates how Government intervention can
benefit the e-commerce in Saudi Arabia.


title:
Measurement of the scalar polarizability within the 5P1/2-6S1/2, 410 nm
  transition in atomic indium

abstract:
  We have completed a new measurement of the Stark shift in 115In within the
410 nm 5P1/2- 6S1/2 transition. We measure the Stark shift constant to be kS= -
122.92(33)kHz/(kV/cm)^2, corresponding to a difference in the 6S1/2 and 5P1/2
state polarizabilities, \Delta\alpha_0, of 1000.2 (2.7) a.u.(in atomic units).
This result is a factor of 30 more precise than previous measurements and is in
excellent agreement with a new theoretical value based on an ab initio
calculation of the wave functions in this three-valence-electron system. The
measurement was performed in an indium atomic beam apparatus, used a GaN laser
diode system, and exploited an FM spectroscopy technique to extract laser
transmission spectra under conditions where our interaction region optical
depth was typically less than 10^-3.