title:
Creation and protection of entanglement in systems out of thermal
  equilibrium

abstract:
  We investigate the creation of entanglement between two quantum emitters
interacting with a realistic common stationary electromagnetic field out of
thermal equilibrium. In the case of two qubits we show that the absence of
equilibrium allows the generation of steady entangled states, which is
inaccessible at thermal equilibrium and is realized without any further
external action on the two qubits. We first give a simple physical
interpretation of the phenomenon in a specific case and then we report a
detailed investigation on the dependence of the entanglement dynamics on the
various physical parameters involved. Sub- and super-radiant effects are
discussed, and qualitative differences in the dynamics concerning both creation
and protection of entanglement according to the initial two-qubit state are
pointed out.


title: From Fuchsian differential equations to integrable QFT

abstract:
  We establish an intriguing correspondence between a special set of classical
solutions of the modified sinh-Gordon equation (i.e., Hitchin's "self-duality"
equations) on a punctured Riemann sphere and a set of stationary states in the
finite-volume Hilbert space of the integrable 2D QFT introduced by V.A. Fateev.
Potential applications of this correspondence to the problem of
non-perturbative quantization of classically integrable non-linear sigma models
are briefly discussed. A detailed account of the results announced in this
letter is contained in a separate publication arXiv:1310.4390.


title: Magnetic Field Structure and Activity of the He-burning Giant 37 Comae

abstract:
  We present the first magnetic map of the late-type giant 37 Com. The Least
Squares Deconvolution (LSD) method and Zeeman Doppler Imaging (ZDI) inversion
technique were applied. The chromospheric activity indicators H?_alpha,
S-index, Ca ii IRT and the radial velocity were also measured. The evolutionary
status of the star has been studied on the basis of state-of-the-art stellar
evolutionary models and chemical abundance analysis. 37 Com appears to be in
the core Helium-burning phase.


title:
Stability Analysis for Discontinuous Galerkin approximations of the
  elastodynamics problem

abstract:
  We consider semi-discrete discontinuous Galerkin approximations of a general
elastodynamics problem, in both {\it displacement} and {\it
displacement-stress} formulations. We present the stability analysis of all the
methods in the natural energy norm and derive optimal a-priori error estimates.
For the displacement-stress formulation, schemes preserving the total energy of
the system are introduced and discussed. We include some numerical experiments
in three dimensions to verify the theory.


title:
Non-hysteretic superconducting quantum interference proximity transistor
  with enhanced responsivity

abstract:
  This letter presents fabrication and characterization of an optimized SQUIPT
(superconducting quantum interference proximity transistor). The present
device, characterized with reduced tunnel junction area and shortened
normal-metal section, demonstrates no hysteresis at low temperatures as we
increased the Josephson inductance of the weak link by decreasing its cross
section. It has consequently almost an order of magnitude improved magnetic
field responsivity as compared to the earlier design. The modulation of both
the current and the voltage across the junction have been measured as a
function of magnetic flux piercing the superconducting loop.


title: Introduction to colloidal dispersions in external fields

abstract:
  Progress in the research area of colloidal dispersions in external fields
within the last years is reviewed. Colloidal dispersions play a pivotal role as
model systems for phase transitions in classical statistical mechanics. In
recent years the leading role of colloids to realize model systems has become
evident not only for equilibrium situations but also far away from equilibrium.
By using external fields (such as shear flow, electric, magnetic or
laseroptical fields as well as confinement), a colloidal suspension can be
brought into nonequilibrium in a controlled way. Various kinds of equilibrium
and nonequilibrium phenomena explored by colloidal dispersions are described
providing also a guide and summary to this special issue. Particular emphasis
is put on the comparison of real-space experiments, computer simulations and
statistical theories.


title:
Multi-Object and Long-Slit Spectroscopy of Very Low Mass Brown Dwarfs in
  Orion Nebular Cluster

abstract:
  We present the results of a H- and K-band multi-object and long-slit
spectroscopic survey of substellar mass candidates in the outer regions of the
Orion Nebula Cluster. The spectra were obtained using MOIRCS on the 8.2-m
Subaru telescope and ISLE on the 1.88-m telescope of Okayama Astronomical
Observatory. Eight out of twelve spectra show strong water absorptions and we
confirm that their effective temperatures are < 3000 K (spectral type > M6)
from a chi-square fit to synthetic spectra. We plot our sources on an HR
diagram overlaid with theoretical isochrones of low-mass objects and identify
three new young brown dwarf candidates. One of the three new candidates is a
cool object near the brown dwarf and planetary mass boundary. Based on our
observations and those of previous studies, we determine the stellar (0.08 <
M/Msun < 1) to substellar (0.03 < M/Msun < 0.08) mass number ratio in the outer
regions of the Orion nebular cluster to be 3.5 +/- 0.8. In combination with the
number ratio reported for the central region (3.3+0.8/-0.7), this result
suggests the number ratio does not simply change with the distance from the
center of the Orion nebular cluster.


title: An optimal bound on the number of moves for open Mancala

abstract:
  We determine the optimal bound for the maximum number of moves required to
reach a periodic configuration of open mancala (also called open owari),
inspired by a popular African game. A mancala move can be interpreted as a map
from the set of compositions of a given integer in itself, thus relating our
result to the study of the corresponding finite dynamical system.


title: Reducing complexes in multidimensional persistent homology theory

abstract:
  The Discrete Morse Theory of Forman appeared to be useful for providing
filtration-preserving reductions of complexes in the study of persistent
homology. So far, the algorithms computing discrete Morse matchings have only
been used for one-dimensional filtrations. This paper is perhaps the first
attempt in the direction of extending such algorithms to multidimensional
filtrations. Initial framework related to Morse matchings for the
multidimensional setting is proposed, and a matching algorithm given by King,
Knudson, and Mramor is extended in this direction. The correctness of the
algorithm is proved, and its complexity analyzed. The algorithm is used for
establishing a reduction of a simplicial complex to a smaller but not
necessarily optimal cellular complex. First experiments with filtrations of
triangular meshes are presented.


title: A remark on the invariance of dimension

abstract:
  Combining Kulpa's proof of the cubical Sperner lemma and a dimension
theoretic idea of van Mill we give a very short proof of the invariance of
dimension, i.e. the statement that cubes [0,1]^n, [0,1]^m are homeomorphic if
and only if n=m. This note is adapted from lecture notes for a course on
general topology.


title: Role of detritus in a spatial food web model with diffusion

abstract:
  One of the central themes in modern ecology is the enduring debate on whether
there is a relationship between the complexity of a biological community and
its stability. In this paper, we focus on the role of detritus and spatial
dispersion on the stability of ecosystems. Using Monte Carlo simulations we
analyze two three level models of food webs: a grazing one with the basal
species (i.e. primary producers) having unlimited food resources and a detrital
one in which the basal species uses detritus as a food resource. While the vast
majority of theoretical studies neglects detritus, from our results it follows
that the detrital food web is more stable than its grazing counterpart, because
the interactions mediated by detritus damp out fluctuations in species'
densities. Since the detritus model is the more complex one in terms of
interaction patterns, our results provide new evidence for the advocates of the
complexity as one of the factors enhancing stability of ecosystems.


title: Inference in nonstationary asymmetric GARCH models

abstract:
  This paper considers the statistical inference of the class of asymmetric
power-transformed $\operatorname{GARCH}(1,1)$ models in presence of possible
explosiveness. We study the explosive behavior of volatility when the strict
stationarity condition is not met. This allows us to establish the asymptotic
normality of the quasi-maximum likelihood estimator (QMLE) of the parameter,
including the power but without the intercept, when strict stationarity does
not hold. Two important issues can be tested in this framework: asymmetry and
stationarity. The tests exploit the existence of a universal estimator of the
asymptotic covariance matrix of the QMLE. By establishing the local asymptotic
normality (LAN) property in this nonstationary framework, we can also study
optimality issues.


title: Stochastic isentropic Euler equations

abstract:
  We study the stochastically forced system of isentropic Euler equations of
gas dynamics with a $\gamma$-law for the pressure. We show the existence of
martingale weak entropy solutions; we also discuss the existence and
characterization of invariant measures in the concluding section.


title:
Analysis of the limiting spectral measure of large random matrices of
  the separable covariance type

abstract:
  Consider the random matrix $\Sigma = D^{1/2} X \widetilde D^{1/2}$ where $D$
and $\widetilde D$ are deterministic Hermitian nonnegative matrices with
respective dimensions $N \times N$ and $n \times n$, and where $X$ is a random
matrix with independent and identically distributed centered elements with
variance $1/n$. Assume that the dimensions $N$ and $n$ grow to infinity at the
same pace, and that the spectral measures of $D$ and $\widetilde D$ converge as
$N,n \to\infty$ towards two probability measures. Then it is known that the
spectral measure of $\Sigma\Sigma^*$ converges towards a probability measure
$\mu$ characterized by its Stieltjes Transform.
  In this paper, it is shown that $\mu$ has a density away from zero, this
density is analytical wherever it is positive, and it behaves in most cases as
$\sqrt{|x - a|}$ near an edge $a$ of its support. A complete characterization
of the support of $\mu$ is also provided. \\ Beside its mathematical interest,
this analysis finds applications in a certain class of statistical estimation
problems.


title:
Probing pairing correlations in Sn isotopes using Richardson-Gaudin
  integrability

abstract:
  Pairing correlations in the even-even A=102-130 Sn isotopes are discussed,
based on the Richardson-Gaudin variables in an exact Woods-Saxon plus reduced
BCS pairing framework. The integrability of the model sheds light on the
pairing correlations, in particular on the previously reported sub-shell
structure.


title:
Dynamical Modeling of NGC 6809: Selecting the best model using Bayesian
  Inference

abstract:
  The precise cosmological origin of globular clusters remains uncertain, a
situation hampered by the struggle of observational approaches in conclusively
identifying the presence, or not, of dark matter in these systems. In this
paper, we address this question through an analysis of the particular case of
NGC 6809. While previous studies have performed dynamical modeling of this
globular cluster using a small number of available kinematic data, they did not
perform appropriate statistical inference tests for the choice of best model
description; such statistical inference for model selection is important since,
in general, different models can result in significantly different inferred
quantities. With the latest kinematic data, we use Bayesian inference tests for
model selection and thus obtain the best fitting models, as well as mass and
dynamic mass-to-light ratio estimates. For this, we introduce a new likelihood
function that provides more constrained distributions for the defining
parameters of dynamical models. Initially we consider models with a known
distribution function, and then model the cluster using solutions of the
spherically symmetric Jeans equation; this latter approach depends upon the
mass density profile and anisotropy $\beta$ parameter. In order to find the
best description for the cluster we compare these models by calculating their
Bayesian evidence. We find smaller mass and dynamic mass-to-light ratio values
than previous studies, with the best fitting Michie model for a constant
mass-to-light ratio of $\Upsilon = 0.90^{+0.14}_{-0.14}$ and
$M_{\text{dyn}}=6.10^{+0.51}_{-0.88} \times 10^4 M_{\odot}$. We exclude the
significant presence of dark matter throughout the cluster, showing that no
physically motivated distribution of dark matter can be present away from the
cluster core.


title: Guaranteed Collision Detection With Toleranced Motions

abstract:
  We present a method for guaranteed collision detection with toleranced
motions. The basic idea is to consider the motion as a curve in the
12-dimensional space of affine displacements, endowed with an object-oriented
Euclidean metric, and cover it with balls. The associated orbits of points,
lines, planes and polygons have particularly simple shapes that lend themselves
well to exact and fast collision queries. We present formulas for elementary
collision tests with these orbit shapes and we suggest an algorithm, based on
motion subdivision and computation of bounding balls, that can give a
no-collision guarantee. It allows a robust and efficient implementation and
parallelization. At hand of several examples we explore the asymptotic behavior
of the algorithm and compare different implementation strategies.


title: First results of the CERN Resonant WISP Search (CROWS)

abstract:
  The CERN Resonant WISP Search (CROWS) probes the existence of Weakly
Interacting Sub-eV Particles (WISPs) like axions or hidden sector photons. It
is based on the principle of an optical light shining through the wall
experiment, adapted to microwaves. Critical aspects of the experiment are
electromagnetic shielding, design and operation of low loss cavity resonators
and the detection of weak sinusoidal microwave signals. Lower bounds were set
on the coupling constant $g = 4.5 \cdot 10^{-8} $GeV$^{-1}$ for axion like
particles with a mass of $m_a = 7.2 \mu$eV. For hidden sector photons, lower
bounds were set for the coupling constant $\chi = 4.1 \cdot 10^{-9}$ at a mass
of $m_{\gamma'} = 10.8 \mu$eV. For the latter we were probing a previously
unexplored region in the parameter space.


title: A Geometric Approach to Radial Correlation Type Problems

abstract:
  A radial probability measure is a probability measure with a density (with
respect to the Lebesgue measure) which depends only on the distances to the
origin. Consider the Euclidean space enhanced with a radial probability
measure. A correlation problem concerns showing whether the radial measure of
the intersection of two symmetric convex bodies is greater than the product of
the radial measures of the two convex bodies. A radial measure satisfying this
property is said to satisfy the correlation property. A major question in this
field is about the correlation property of the (standard) Gaussian measure. The
main result in this paper is a theorem suggesting a sufficient condition for a
radial measure to satisfy the correlation property. A consequence of the main
theorem will be a proof of the correlation property of the Gaussian measure.


title: Group rings with Lie metabelian set of symmetric elements

abstract:
  Let $R$ be a commutative ring of characteristic zero and $G$ an arbitrary
group. In the present paper we classify the groups $G$ for which the set of
symmetric elements with respect to the classical involution of the group ring
$RG$ is Lie metabelian.


title: The weak Cartan property for the p-fine topology on metric spaces

abstract:
  We study the p-fine topology on complete metric spaces equipped with a
doubling measure supporting a p-Poincare inequality, 1 < p< oo. We establish a
weak Cartan property, which yields characterizations of the p-thinness and the
p-fine continuity, and allows us to show that the p-fine topology is the
coarsest topology making all p-superharmonic functions continuous. Our
p-harmonic and superharmonic functions are defined by means of scalar-valued
upper gradients and do not rely on a vector-valued differentiable structure.


title: Slicing inequalities for subspaces of $L_p.$

abstract:
  We show that the hyperplane conjecture holds for the classes of
$k$-intersection bodies with arbitrary measures in place of volume.


title: Instability windows and evolution of rapidly rotating neutron stars

abstract:
  We consider an instability of rapidly rotating neutron stars in low-mass
X-ray binaries (LMXBs) with respect to excitation of r-modes (which are
analogous to Earth's Rossby waves controlled by the Coriolis force). We argue
that finite temperature effects in the superfluid core of a neutron star lead
to a resonance coupling and enhanced damping (and hence stability) of
oscillation modes at certain stellar temperatures. Using a simple
phenomenological model we demonstrate that neutron stars with high spin
frequency may spend a substantial amount of time at these `resonance'
temperatures. This finding allows us to explain puzzling observations of hot
rapidly rotating neutron stars in LMXBs and to predict a new class of hot,
non-accreting, rapidly rotating neutron stars, some of which may have already
been observed and tentatively identified as quiescent LMXB (qLMXB) candidates.
We also impose a new theoretical limit on the neutron star spin frequency,
explaining the cut-off spin frequency ~730 Hz, following from the statistical
analysis of accreting millisecond X-ray pulsars. Besides explaining the
observations, our model provides a new tool to constrain superdense matter
properties comparing measured and theoretically predicted resonance
temperatures.


title:
Magnesium in the atmosphere of the planet HD209458b: Observations of the
  thermosphere-exosphere transition region

abstract:
  We report new near ultraviolet HST/STIS observations of atmospheric
absorptions during the planetary transit of HD209458b. We detect absorption in
atomic magnesium (MgI), while no signal has been detected in the lines of
singly ionized magnesium (MgII). We measure the MgI atmospheric absorption to
be 6.2+/-2.9% in the velocity range from -62 to -19 km/s. The detection of
atomic magnesium in the planetary upper atmosphere at a distance of several
planetary radii gives a first view into the transition region between the
thermosphere and the exobase, where atmospheric escape takes place. We estimate
the electronic densities needed to compensate for the photo-ionization by
dielectronic recombination of Mg+ to be in the range of 10^8-10^9 cm^{-3}. Our
finding is in excellent agreement with model predictions at altitudes of
several planetary radii.
  We observe MgI atoms escaping the planet, with a maximum radial velocity (in
the stellar rest frame) of -60 km/s. Because magnesium is much heavier than
hydrogen, the escape of this species confirms previous studies that the
planet's atmosphere is undergoing hydrodynamic escape. We compare our
observations to a numerical model that takes the stellar radiation pressure on
the MgI atoms into account. We find that the MgI atoms must be present at up to
~7.5 planetari radii altitude and estimate an MgI escape rate of ~3x10^7 g/s.
Compared to previous evaluations of the escape rate of HI atoms, this
evaluation is compatible with a magnesium abundance roughly solar. A hint of
absorption, detected at low level of significance, during the post-transit
observations, could be interpreted as a MgI cometary-like tail. If true, the
estimate of the absorption by MgI would be increased to a higher value of about
8.8+/-2.1%.


title:
Direct observation of Dirac cones and a flatband in a honeycomb lattice
  for polaritons

abstract:
  Two-dimensional lattices of coupled micropillars etched in a planar
semiconductor microcavity offer a workbench to engineer the band structure of
polaritons. We report experimental studies of honeycomb lattices where the
polariton low-energy dispersion is analogous to that of electrons in graphene.
Using energy-resolved photoluminescence we directly observe Dirac cones, around
which the dynamics of polaritons is described by the Dirac equation for
massless particles. At higher energies, we observe p orbital bands, one of them
with the nondispersive character of a flatband. The realization of this
structure which holds massless, massive and infinitely massive particles opens
the route towards studies of the interplay of dispersion, interactions, and
frustration in a novel and controlled environment.


title: Characteristics of polar coronal hole jets

abstract:
  High spatial- and temporal-resolution images of coronal hole regions show a
dynamical environment where mass flows and jets are frequently observed. These
jets are believed to be important for the coronal heating and the acceleration
of the fast solar wind. We studied the dynamics of two jets seen in a polar
coronal hole with a combination of imaging from EIS and XRT onboard Hinode. We
observed drift motions related to the evolution and formation of these
small-scale jets, which we tried to model as well. We found observational
evidence that supports the idea that polar jets are very likely produced by
multiple small-scale reconnections occurring at different times in different
locations. These eject plasma blobs that flow up and down with a motion very
similar to a simple ballistic motion. The associated drift speed of the first
jet is estimated to be $\approx$ 27 km s$^{-1}$. The average outward speed of
the first jet is $\approx 171$ km s$^{-1}$, well below the escape speed, hence
if simple ballistic motion is considered, the plasma will not escape the Sun.
The second jet was observed in the south polar coronal hole with three XRT
filters, namely, C$_{-}$poly, Al$_{-}$poly, and Al$_{-}$mesh filters. We
observed that the second jet drifted at all altitudes along the jet with the
same drift speed of $\simeq$ 7 km s$^{-1}$. The enhancement in the light curves
of low-temperature EIS lines in the later phase of the jet lifetime and the
shape of the jet's stack plots suggests that the jet material is falls back,
and most likely cools down. To support this conclusion, the observed drifts
were interpreted within a scenario where reconnection progressively shifts
along a magnetic structure, leading to the sequential appearance of jets of
about the same size and physical characteristics. On this basis, we also
propose a simple qualitative model that mimics the observations.


title: Scalable Frames and Convex Geometry

abstract:
  The recently introduced and characterized scalable frames can be considered
as those frames which allow for perfect preconditioning in the sense that the
frame vectors can be rescaled to yield a tight frame. In this paper we define
$m$-scalability, a refinement of scalability based on the number of non-zero
weights used in the rescaling process, and study the connection between this
notion and elements from convex geometry. Finally, we provide results on the
topology of scalable frames. In particular, we prove that the set of scalable
frames with "small" redundancy is nowhere dense in the set of frames.


title: Forbidding just one intersection, for permutations

abstract:
  We prove that for $n$ sufficiently large, if $A$ is a family of permutations
of $\{1,2,\ldots,n\}$ with no two permutations in $\mathcal{A}$ agreeing
exactly once, then $|\mathcal{A}| \leq (n-2)!$, with equality holding only if
$\mathcal{A}$ is a coset of the stabilizer of 2 points. We also obtain a
Hilton-Milner type result, namely that if $\mathcal{A}$ is such a family which
is not contained within a coset of the stabilizer of 2 points, then it is no
larger than the family $\{\sigma \in S_{n}:\ \sigma(1)=1,\sigma(2)=2,\
\#\{\textrm{fixed points of}\sigma \geq 5\} \neq 1\} \cup \{(1\ 3)(2\ 4),(1\
4)(2\ 3),(1\ 3\ 2\ 4),(1\ 4\ 2\ 3)\}$.
  We conjecture that for $t \in \mathbb{N}$, and for $n$ sufficiently large
depending on $t$, if $\mathcal{A}$ is family of permutations of
$\{1,2,\ldots,n\}$ with no two permutations in $\mathcal{A}$ agreeing exactly
$t-1$ times, then $|\mathcal{A}| \leq (n-t)!$, with equality holding only if
$\mathcal{A}$ is a coset of the stabilizer of $t$ points. This can be seen as a
permutation analogue of a conjecture of Erd\H{o}s on families of $k$-element
sets with a forbidden intersection, proved by Frankl and F\"uredi in [P. Frankl
and Z. F\"uredi, Forbidding Just One Intersection, Journal of Combinatorial
Theory, Series A, Volume 39 (1985), pp. 160-176].


title: Spectral dimension in graph models of causal quantum gravity

abstract:
  The phenomenon of scale dependent spectral dimension has attracted special
interest in the quantum gravity community over the last eight years. It was
first observed in computer simulations of the causal dynamical triangulation
(CDT) approach to quantum gravity and refers to the reduction of the spectral
dimension from 4 at classical scales to 2 at short distances. Thereafter
several authors confirmed a similar result from different approaches to quantum
gravity. Despite the contribution from different approaches, no analytical
model was proposed to explain the numerical results as the continuum limit of
CDT. In this thesis we introduce graph ensembles as toy models of CDT and show
that both the continuum limit and a scale dependent spectral dimension can be
defined rigorously. First we focus on a simple graph ensemble, the random comb.
It does not have any dynamics from the gravity point of view, but serves as an
instructive toy model to introduce the characteristic scale of the graph, study
the continuum limit and define the scale dependent spectral dimension. Having
defined the continuum limit, we study the reduction of the spectral dimension
on more realistic toy models, the multigraph ensembles, which serve as a radial
approximation of CDT. We focus on the (recurrent) multigraph approximation of
the two-dimensional CDT whose ensemble measure is analytically controlled. The
latter comes from the critical Galton-Watson process conditioned on
non-extinction. Next we turn our attention to transient multigraph ensembles,
corresponding to higher-dimensional CDT. Firstly we study their fractal
properties and secondly calculate the scale dependent spectral dimension and
compare it to computer simulations. We comment further on the relation between
Horava-Lifshitz gravity, asymptotic safety, multifractional spacetimes and
CDT-like models.


title:
A new method to simulate the Bingham and related distributions in
  directional data analysis with applications

abstract:
  A new acceptance-rejection method is proposed and investigated for the
Bingham distribution on the sphere using the angular central Gaussian
distribution as an envelope. It is shown to have high efficiency and to be
straightfoward to use. The method can also be extended to Fisher and
Fisher-Bingham distributions on spheres and related manifolds.


title:
Towards an Assessment-oriented Model for External Information System
  Quality Characterization

abstract:
  Information System Quality (ISQ) management discipline requires a set of
assessment mechanisms to evaluate external quality characteristics that are
influenced by the environmental parameters and impacted by the ecosystem
factors. The present paper suggests a new assessment oriented model that takes
into consideration all facets of each external quality feature. The proposed
model, named RatQual, gives a hierarchical categorization for quality. RatQual
is designed to quantify dependent-environment qualities by considering
internal, external and in use aspects. This model is supported by a tool that
automates the assessment process. This tool gives assistance in quality
evolution planning and serves for periodical monitoring operations used to
enhance and improve information system quality.


title: Spurious finite-size instabilities in nuclear energy density functionals

abstract:
  It is known that some well-established parametrizations of the EDF do not
always provide converged results for nuclei and a qualitative link between this
finding and the appearance of finite-size instabilities of SNM near saturation
density when computed within the RPA has been pointed out. We seek for a
quantitative and systematic connection between the impossibility to converge
self-consistent calculations of nuclei and the occurrence of finite-size
instabilities in SNM for the example of scalar-isovector (S=0, T=1)
instabilities of the standard Skyrme EDF. We aim to establish a stability
criterion based on computationally-friendly RPA calculations of SNM that is
independent on the functional form of the EDF and that can be utilized during
the adjustment of its coupling constants. Tuning the coupling constant $C^{\rho
\Delta\rho}_{1}$ of the gradient term that triggers scalar-isovector
instabilities of the standard Skyrme EDF, we find that the occurrence of
instabilities in finite nuclei depends strongly on the numerical scheme used to
solve the self-consistent mean-field equations. The link to instabilities of
SNM is made by extracting the lowest density $\rho_{\text{crit}}$ at which a
pole appears at zero energy in the RPA response function when employing the
critical value of the coupling constant $C^{\rho \Delta\rho}_{1}$ extracted in
nuclei. Our analysis suggests a two-fold stability criterion to avoid
scalar-isovector instabilities: (i) The density $\rho_{\text{min}}$
corresponding to the lowest pole in the RPA response function should be larger
than about 1.2 times the saturation density; (ii) one needs to verify that
$\rho_{p}(q_{\text{pq}})$ exhibits a distinct global minimum and is not a
decreasing function for large transferred momenta.


title:
Self-consistent energy approximation for orbital-free density-functional
  theory

abstract:
  Employing a local formula for the electron-electron interaction energy, we
derive a self-consistent approximation for the total energy of a general
$N$-electron system. Our scheme works as a local variant of the Thomas-Fermi
approximation and yields the total energy and density as a function of the
external potential, the number of electrons, and the chemical potential
determined upon normalization. Our tests for Hooke's atoms, jellium, and model
atoms up to $\sim 1000$ electrons show that reasonable total energies can be
obtained with almost a negligible computational cost. The results are also
consistent in the important large-$N$ limit.


title:
Product-form solutions for a class of structured multi-dimensional
  Markov processes

abstract:
  Motivated by queueing systems with heterogeneous parallel servers, we
consider a class of structured multi-dimensional Markov processes whose state
space can be partitioned into two parts: a finite set of boundary states and a
structured multi-dimensional set of states, exactly one dimension of which is
infinite. Using separation of variables, we show that the equilibrium
distribution, typically of the queue length, can be represented as a linear
combination of product forms. For an important subclass of queueing systems, we
characterize explicitly the waiting time distribution in terms of mixtures of
exponentials.


title:
A New Generation of Brain-Computer Interface Based on Riemannian
  Geometry

abstract:
  Based on the cumulated experience over the past 25 years in the field of
Brain-Computer Interface (BCI) we can now envision a new generation of BCI.
Such BCIs will not require training; instead they will be smartly initialized
using remote massive databases and will adapt to the user fast and effectively
in the first minute of use. They will be reliable, robust and will maintain
good performances within and across sessions. A general classification
framework based on recent advances in Riemannian geometry and possessing these
characteristics is presented. It applies equally well to BCI based on
event-related potentials (ERP), sensorimotor (mu) rhythms and steady-state
evoked potential (SSEP). The framework is very simple, both algorithmically and
computationally. Due to its simplicity, its ability to learn rapidly (with
little training data) and its good across-subject and across-session
generalization, this strategy a very good candidate for building a new
generation of BCIs, thus we hereby propose it as a benchmark method for the
field.


title: Scaling of Chaos in Strongly Nonlinear Lattices

abstract:
  Although it is now understood that chaos in complex classical systems is the
foundation of thermodynamic behavior, the detailed relations between the
microscopic properties of the chaotic dynamics and the macroscopic
thermodynamic observations still remain mostly in the dark. In this work, we
numerically analyze the probability of chaos in strongly nonlinear Hamiltonian
systems and find different scaling properties depending on the nonlinear
structure of the model. We argue that these different scaling laws of chaos
have definite consequences for the macroscopic diffusive behavior, as chaos is
the microscopic mechanism of diffusion. This is compared with previous results
on chaotic diffusion [New J.\ Phys.\ 15, 053015 (2013)], and a relation between
microscopic chaos and macroscopic diffusion is established.


title: Overshooting by convective settling

abstract:
  We study a process of slow mixing in stars with convective envelopes, which
is driven by the settling of cool downward plumes below the base of the
convection zone. If a small fraction (of order $10^{-7}$) of the material
cooled at the surface retains a significant entropy deficit while descending in
plumes, it can reach the depth where lithium burning takes place. The model
calculates the thermal response and mixing below the convection zone due to the
settling process, assuming that the plumes arrive at the base of the convection
zone with a broad range of entropy contrasts. We obtain a good fit to the
observed lithium depletion in the Sun by assuming that the settling mass flux
is distributed with respect to the entropy contrast as a power law with a slope
around -2. We find convective settling to have a negligible influence on the
stratification below the convection zone, although mixing induced by it could
modify the gradient of helium concentration.


title: On the singular hyperbolicity of star flows

abstract:
  We prove for a generic star vector field $X$ that, if for every chain
recurrent class $C$ of $X$ all singularities in $C$ have the same index, then
the chain recurrent set of $X$ is singular hyperbolic. We also prove that every
Lyapunov stable chain recurrent class of $X$ is singular hyperbolic. As a
corollary, we prove that the chain recurrent set of a generic 4-dimensional
star flow is singular hyperbolic.


title: Defect and equivalence of unitary matrices. The Fourier case

abstract:
  Consider the real space D_U of directions moving into which from a unitary N
x N matrix U we do not disturb its unitarity and the moduli of its entries in
the first order. dim( D_U ) is called the defect of U and denoted D(U). We give
an account of Alexander Karabegov's theory where D_U is parametrized by the
imaginary subspace of the eigenspace, associated with lambda = 1, of a certain
unitary operator I_U on the N x N complex matrices, and where D(U) is the
multiplicity of 1 in the spectrum of I_U. This characterization allows us to
establish dependence of D(U_1 x ... x U_r) - where x stands for the Kronecker
product - on D(U_k)'s, to derive formulas expressing D(F) for a Fourier matrix
F of the size being a power of a prime number, as well as to show the
multiplicativity of D(F) with respect to Kronecker factors of F if their sizes
are pairwise relatively prime. Also partly due to the role of symmetries of U
in the determination of the eigenspaces of I_U we study the 'permute and
enphase' symmetries and equivalence of Fourier matrices, associated with
arbitrary finite abelian groups.


title: On the Tractability of Minimal Model Computation for Some CNF Theories

abstract:
  Designing algorithms capable of efficiently constructing minimal models of
CNFs is an important task in AI. This paper provides new results along this
research line and presents new algorithms for performing minimal model finding
and checking over positive propositional CNFs and model minimization over
propositional CNFs. An algorithmic schema, called the Generalized Elimination
Algorithm (GEA) is presented, that computes a minimal model of any positive
CNF. The schema generalizes the Elimination Algorithm (EA) [BP97], which
computes a minimal model of positive head-cycle-free (HCF) CNF theories. While
the EA always runs in polynomial time in the size of the input HCF CNF, the
complexity of the GEA depends on the complexity of the specific eliminating
operator invoked therein, which may in general turn out to be exponential.
Therefore, a specific eliminating operator is defined by which the GEA
computes, in polynomial time, a minimal model for a class of CNF that strictly
includes head-elementary-set-free (HEF) CNF theories [GLL06], which form, in
their turn, a strict superset of HCF theories. Furthermore, in order to deal
with the high complexity associated with recognizing HEF theories, an
"incomplete" variant of the GEA (called IGEA) is proposed: the resulting
schema, once instantiated with an appropriate elimination operator, always
constructs a model of the input CNF, which is guaranteed to be minimal if the
input theory is HEF. In the light of the above results, the main contribution
of this work is the enlargement of the tractability frontier for the minimal
model finding and checking and the model minimization problems.


title: Easy Accurate Reading and Writing of Floating-Point Numbers

abstract:
  Presented here are algorithms for converting between (decimal)
scientific-notation and (binary) IEEE-754 double-precision floating-point
numbers. By employing a rounding integer quotient operation these algorithms
are much simpler than those previously published. The values are stable under
repeated conversions between the formats. Unlike Java-1.8, the scientific
representations generated use only the minimum number of mantissa digits needed
to convert back to the original binary values.


title:
A closed formula for the topological entropy of multimodal maps based on
  min-max symbols

abstract:
  Topological entropy is a measure of complex dynamics. In this regard,
multimodal maps play an important role when it comes to study low-dimensional
chaotic dynamics or explain some features of higher dimensional complex
dynamics with conceptually simple models. In the first part of this paper an
analytical formula for the topological entropy of twice differentiable
multimodal maps is derived, and some basic properties are studied. This
expression involves the so-called min-max symbols, which are closely related to
the kneading symbols. Furthermore, its proof leads to a numerical algorithm
that simplifies a previous one also based on min-max symbols. In the second
part of the paper this new algorithm is used to compute the topological entropy
of different modal maps. Moreover, it compares favorably to the previous
algorithm when computing the topological entropy of the bi- and tri-modal maps
considered in the numerical simulations.


title: Tests for covariance matrix with fixed or divergent dimension

abstract:
  Testing covariance structure is of importance in many areas of statistical
analysis, such as microarray analysis and signal processing. Conventional tests
for finite-dimensional covariance cannot be applied to high-dimensional data in
general, and tests for high-dimensional covariance in the literature usually
depend on some special structure of the matrix. In this paper, we propose some
empirical likelihood ratio tests for testing whether a covariance matrix equals
a given one or has a banded structure. The asymptotic distributions of the new
tests are independent of the dimension.


title: On the solution of the linear matrix equation $X=Af(X)B+C$

abstract:
  In this paper, we derive a formula to compute the solution of the linear
matrix equation $X=Af(X)B+C$ via finding any solution of a specific Stein
matrix equation $\mathcal{X}=\mathcal{A} \mathcal{X} \mathcal{B}+\mathcal{C}$,
where the linear (or anti-linear) matrix operator $f$ is period-$n$. According
to this formula, we should pay much attention to solve the Stein matrix
equation from recently famous numerical methods. For instance, Smith-type
iterations, Bartels-Stewart algorithm, and etc.. Moreover, this transformation
is used to provide necessary and sufficient conditions of the solvable of the
linear matrix equation. On the other hand, it can be proven that the general
solution of the linear matrix equation can be presented by the general solution
of the Stein matrix equation. The necessary condition of the uniquely solvable
of the linear matrix equation is developed. It is shown that several
representations of this formula are coincident. Some examples are presented to
illustrate and explain our results.


title:
Finding Alternate Paths in the Internet:A Survey of Techniques for
  End-to-End Path Discovery

abstract:
  The Internet provides physical path diversity between a large number of
hosts, making it possible for networks to use alternative paths when one path
fails to deliver the required Quality of Service. However, for various reasons,
many established protocols (e.g. de facto Internet inter-domain routing
protocol, Border-Gateway Protocol - BGP) do not fully exploit such alternate
paths. This paper surveys research into techniques for discovering end-to-end
alternate paths, including those based on monitoring path performance, choosing
paths that are maximally disjoint, and in routing across multiple paths. It
surveys proposals for making BGP better able to exploit multiple paths and how
multi-homing can create alternate paths. It also describes how alternate paths
can be realized through detour routing (application layer mechanisms) and
routing deflections (network layer mechanisms). It also discusses Fast Re-Route
techniques for construction of backup routes. It concludes by surveying open
research issues into the discovery and use of alternate paths in the Internet.


title: Organic species in Infrared Dark Clouds

abstract:
  It is currently assumed that infrared dark clouds (IRDCs) represent the
earliest evolutionary stages of high-mass stars ($>$ 8 M$_{\odot}$).
Submillimeter and millimeter-wave studies performed over the past 15 years show
that IRDCs possess a broad variety of properties, and hence a wide range of
problems and questions that can be tackled. In this paper, we report an
investigation of the molecular composition and chemical processes in two groups
of IRDCs. Using the Mopra, APEX, and IRAM radio telescopes over the last four
years, we have collected molecular line data for CO, H$_2$CO, HNCO, CH$_3$CCH,
CH$_3$OH, CH$_3$CHO, CH$_3$OCHO, and CH$_3$OCH$_3$. For all of these species we
estimated molecular abundances. We then undertook chemical modeling studies,
concentrating on the source IRDC028.34+0.06, and compared observed and modeled
abundances. This comparison showed that to reproduce observed abundances of
complex organic molecules (COMs), a 0-D gas-grain model with constant physical
conditions is not sufficient. We achieved greater success with the use of a
warm-up model, in which warm-up from 10 K to 30 K occurs following a cold
phase.


title: Charmonium-like states from scattering on the lattice

abstract:
  Three charmonium-like states were studied using lattice QCD. The candidate
for X(3872) was found slightly below DD* threshold in the channel with
J^PC=1^++ and I=0, where cc as well as DD* and $J/\psi \omega$ interpolating
operators were used. A charmonium-like channel with J^PC=1^+- and I=1 was also
studied, as the recently discovered Z_c^+(3900) might reside there. Here
$J/\psi \pi$ and DD* scattering states were found, but no candidate for the
Z_c^+(3900). We present also preliminary results for the J^PC=0^++ charmonium
channel, where cc, DD and $J/\psi \omega$ interpolating operators were used. A
candidate for a resonance, chi_c0^', that couples to DD in J^PC=0^++ was found.


title: On reference frames and the definition of space in a general spacetime

abstract:
  First, we review local concepts defined previously. A (local) reference frame
$\mathrm{F}$ can be defined as an equivalence class of admissible spacetime
charts (coordinate systems) having a common domain $\mathrm{U}$ and exchanging
by a spatial coordinate change. The associated (local) physical space is made
of the world lines having constant space coordinates in any chart of the class.
Second, we introduce new, global concepts. The data of a non-vanishing global
vector field $\,v\,$ defines a global "reference fluid". The associated global
physical space is made of the maximal integral curves of that vector field.
Assume that, in any of the charts which make some reference frame $\mathrm{F}$:
(i) any of those integral curves $l$ has constant space coordinates $x^j$, and
(ii) the mapping $l\mapsto (x^j)$ is one-to-one. In that case, the local space
can be identified with a part (an open subset) of the global space.


title: Novel Higgs-to-125 GeV Higgs boson decays in the complex NMSSM

abstract:
  In the Next-to-Minimal Supersymmetric Standard Model (NMSSM) a variety of
parameter configurations yields a Higgs boson consistent with the one observed
at the LHC. Additionally, the Higgs sector of the model can contain explicit
CP-violating phases even at the tree level, in contrast with the Minimal
Supersymmetric Standard Model (MSSM). In this article we present the one-loop
Higgs boson mass matrix of the complex NMSSM in the
renormalisation-group-improved effective potential approach. We also present
the trilinear Higgs boson self-couplings as well as various partial decay
widths of a generic CP-mixed Higgs boson in the model. We then analyse a very
interesting phenomenological scenario wherein the decay of a relatively light
pseudoscalar-like Higgs boson into ~ 125 GeV SM-like Higgs boson(s) is induced
by non-zero CP-violating phases. We discuss in detail a few benchmark cases in
which such a decay can contribute significantly to the production of SM-like
Higgs bosons at the LHC on top of the gluon fusion process. It can thus be
partially responsible for the gamma.gamma excess near 125 GeV due to the
subsequent decay of the SM-like Higgs boson. Such a scenario is extremely
difficult to realize in the complex MSSM and, if probed at the LHC, it could
provide an indication of the non-minimal nature of supersymmetry.


title: On a Correlation Inequality for Cauchy Type Measures

abstract:
  In this paper we present a correlation inequality with respect to Cauchy type
measures. To prove our inequality, we transport the problem onto the Riemannian
sphere then state and solve some special cases for a spherical correlation
problem. This method, as we shall explain, opens up a new class of interesting
problems related to correlation type inequalities.


title: Superconductivity in a new layered bismuth oxyselenide: LaO0.5F0.5BiSe2

abstract:
  We report superconductivity in a new layered bismuth oxyselenide
LaO0.5F0.5BiSe2 with the ZrCuSiAs-type structure composed of alternating
superconducting BiSe2 and blocking LaO layers. The superconducting transition
temperature is TC = 2.6K, as revealed from DC magnetization, resistivity and
muon spin rotation (muSR) experiments. DC magnetization measurements indicate a
superconducting volume fraction of approximately 80%, which is at least twice
higher in comparison to that found in corresponding sulphide LaO0.5F0.5BiS2.
Importantly, the bulk character of superconductivity in LaO0.5F0.5BiSe2 was
confirmed by muSR.


title:
Purely singular continuous spectrum for CMV operators generated by
  subshifts

abstract:
  We prove uniform absence of point spectrum for CMV operators corresponding to
the period doubling subshift. We also prove almost sure absence of point
spectrum for CMV operators corresponding to a class of Sturmian subshifts.
Lastly, we prove almost sure absence of point spectrum for CMV operators
corresponding to some subshifts generated by a coding of a rotation.


title: Ekpyrotic Perturbations With Small Non-Gaussian Corrections

abstract:
  The entropic mechanism for producing nearly scale-invariant density
perturbations in a contracting ekpyrotic universe relies on having an unstable
scalar potential. Here we develop a variant of this mechanism (recently
proposed by Qiu, Gao and Saridakis, and by Li), in which there exists a
non-trivial coupling between adiabatic and entropic fields, and where an
unstable potential is not required. In the model nearly scale-invariant entropy
perturbations are generated first. Remarkably, we find that the bispectrum of
these perturbations vanishes, with the values of the non-Gaussianity parameters
of local, equilateral and orthogonal type all exactly zero. Subsequently, the
entropy perturbations can be converted into curvature perturbations by a
variety of mechanisms. The bispectrum of the curvature perturbations depends on
the non-linearity of the conversion process and is thus more model-dependent -
however, for an efficient conversion process the final bispectrum remains
small. The only distinguishing feature compared to single-field slow-roll
inflationary models is an absence of primordial gravitational waves. Thus the
present model provides a perfect match to current data from the PLANCK
satellite.


title: Statistics of cosmic density profiles from perturbation theory

abstract:
  The joint probability distribution function (PDF) of the density within
multiple concentric spherical cells is considered. It is shown how its cumulant
generating function can be obtained at tree order in perturbation theory as the
Legendre transform of a function directly built in terms of the initial
moments. In the context of the upcoming generation of large-scale structure
surveys, it is conjectured that this result correctly models such a function
for finite values of the variance. Detailed consequences of this assumption are
explored. In particular the corresponding one-cell density probability
distribution at finite variance is computed for realistic power spectra, taking
into account its scale variation. It is found to be in agreement with
$\Lambda$-CDM simulations at the few percent level for a wide range of density
values and parameters. Related explicit analytic expansions at the low and high
density tails are given. The conditional (at fixed density) and marginal
probability of the slope -- the density difference between adjacent cells --
and its fluctuations is also computed from the two-cells joint PDF; it also
compares very well to simulations, in particular in under-dense regions, with a
significant reduced cosmic scatter compared to over-dense regions. It is
emphasized that this could prove useful when studying the statistical
properties of voids as it can serve as a statistical indicator to test gravity
models and/or probe key cosmological parameters.


title:
Large-Scale Sensor Network Localization via Rigid Subnetwork
  Registration

abstract:
  In this paper, we describe an algorithm for sensor network localization (SNL)
that proceeds by dividing the whole network into smaller subnetworks, then
localizes them in parallel using some fast and accurate algorithm, and finally
registers the localized subnetworks in a global coordinate system. We
demonstrate that this divide-and-conquer algorithm can be used to leverage
existing high-precision SNL algorithms to large-scale networks, which could
otherwise only be applied to small-to-medium sized networks. The main
contribution of this paper concerns the final registration phase. In
particular, we consider a least-squares formulation of the registration problem
(both with and without anchor constraints) and demonstrate how this otherwise
non-convex problem can be relaxed into a tractable convex program. We provide
some preliminary simulation results for large-scale SNL demonstrating that the
proposed registration algorithm (together with an accurate localization scheme)
offers a good tradeoff between run time and accuracy.


title:
Spontaneous breaking of isotropy observed in the electronic transport of
  rare-earth tritellurides

abstract:
  We show that the isotropic conductivity in the normal state of rare-earth
tritelluride RTe_3 compounds is broken by the occurrence of the unidirectional
charge density wave (CDW) in the (a,c) plane below the Peierls transition
temperature. In contrast with quasi-one-dimensional systems, the resistivity
anomaly associated with the CDW transition is strong in the direction
perpendicular to the CDW wave vector Q (a-axis) and very weak in the CDW wave
vector Q direction (c-axis). We qualitatively explain this result by
calculating the electrical conductivity for the electron dispersion with
momentum-dependent CDW gap as determined by angle-resolved photoemission
spectroscopy (ARPES).


title: Novel Rattling of K Atoms in Aluminium-Doped Defect Pyrochlore Tungstate

abstract:
  Rattling dynamics have been identified as fundamental to superconductivity in
defect pyrochlore osmates and aluminium vanadium intermetallics, as well as low
thermal conductivity in clathrates and filled skutterudites. Combining
inelastic neutron scattering (INS) measurements and ab initio molecular
dynamics (MD) simulations, we use a new approach to investigate rattling in the
Al-doped defect pyrochlore tungstates: AAl0.33W1.67O6 (A = K, Rb, Cs). We find
that although all the alkali metals rattle, the rattling of the K atoms is
unique, involving local diffusion within a cage as well as vibrations at a
range of frequencies. We show that the novel K rattling is driven by the strong
anharmonicity and anisotropy of the local potentials around the K atoms, both
of which are a consequence of the small size of the K rattler. Our findings may
open new possibilities for phonon engineering in thermoelectric materials.


title: On Lehmer Binomial Series

abstract: We give evaluations in closed form of certain Lehmer-binomial series


title:
Sudden synchrony leaps accompanied by frequency multiplications in
  neuronal activity

abstract:
  A classical view of neural coding relies on temporal firing synchrony among
functional groups of neurons; however the underlying mechanism remains an
enigma. Here we experimentally demonstrate a mechanism where time-lags among
neuronal spiking leap from several tens of milliseconds to nearly zero-lag
synchrony. It also allows sudden leaps out of synchrony, hence forming short
epochs of synchrony. Our results are based on an experimental procedure where
conditioned stimulations were enforced on circuits of neurons embedded within a
large-scale network of cortical cells in vitro and are corroborated by
simulations of neuronal populations. The underlying biological mechanisms are
the unavoidable increase of the neuronal response latency to ongoing
stimulations and temporal or spatial summation required to generate evoked
spikes. These sudden leaps in and out of synchrony may be accompanied by
multiplications of the neuronal firing frequency, hence offering reliable
information-bearing indicators which may bridge between the two principal
neuronal coding paradigms.


title: Primes Solutions Of Linear Diophantine Equations

abstract:
  Let k => 1, m => 1 be small fixed integers, gcd(k, m) = 1. This note develops
some techniques for proving the existence of infinitely many primes solutions x
= p, and y = q of the linear Diophantine equation y = mx + k.


title: Parameterized Differential Equations over k((t))(x)

abstract:
  In this article, we consider the inverse Galois problem for parameterized
differential equations over k((t))(x) with k any field of characteristic zero
and use the method of patching over fields due to Harbater and Hartmann. As an
application, we prove that every connected semisimple k((t))-split linear
algebraic group is a parameterized Galois group over k((t))(x).


title:
Simultaneous control of optical dipole force and coherence creation by
  super-Gaussian femtosecond pulses in lambda-like atomic systems

abstract:
  We report a study on the optical dipole force on a beam of neutral
three-level like atomic system induced by a femtosecond super-Gaussian pulse.
We show that maximum coherence between the ground state |1> and the excited
state |2> could be achieved using a train of femtosecond pulses. In addition,
it is possible to control the trajectory of the atoms in an atomic beam by
using the same scheme. The robustness of the scheme against the variation of
the pulse parameters is also investigated.


title: On quantum state of numbers

abstract:
  We introduce the notions of quantum characteristic and quantum flatness for
arbitrary rings. More generally, we develop the theory of quantum integers in a
ring and show that the hypothesis of quantum flatness together with positive
quantum characteristic generalizes the usual notion of prime positive
characteristic. We also explain how one can define quantum rational numbers in
a ring and introduce the notion of twisted powers. These results play an
important role in many different areas of mathematics and will also be quite
useful in a subsequent work of the authors.


title:
The effect of foreground subtraction on cosmological measurements from
  Intensity Mapping

abstract:
  We model a 21 cm intensity mapping survey in the redshift range 0.01<z<1.5
designed to simulate the skies as seen by future radio telescopes such as the
Square Kilometre Array (SKA), including instrumental noise and Galactic
foregrounds. In our pipeline, we remove the introduced Galactic foregrounds
with a fast independent component analysis (fastica) technique. We present the
power spectrum of the large-scale matter distribution, C(l), before and after
the application of this foreground removal method and calculate the resulting
systematic errors. We attempt to reduce systematics in the foreground
subtraction by optimally masking the maps to remove high foregrounds in the
Galactic plane. Our simulations show a certain level of bias remains in the
power spectrum at all scales l<400. At large-scales l<30 this bias is
particularly significant. We measure the impact of these systematic effects in
two different ways: firstly we fit cosmological parameters to the broadband
shape of the power spectrum and secondly we extract the position of the Baryon
Acoustic Oscillations (BAO). In the first analysis, we find that the
systematics introduce an significant shift in the best fit cosmological
parameters at the 2 to 3 sigma level which depends on the masking and noise
levels. However, cosmic distances can be recovered in an unbiased way after
foreground removal at all simulated redshifts by fitting the BAOs in the power
spectrum. We conclude that further advances in foreground removal are needed in
order to recover unbiased information from the broadband shape of the power
spectrum, however, intensity mapping experiments will be a powerful tool for
mapping cosmic distances across a wide redshift range.


title: Magnetization and pressures at nonzero magnetic fields in QCD

abstract:
  Two approaches are pursued to determine the magnetization of the QCD vacuum
at zero and nonzero temperatures using lattice simulations. The first method
builds on pressure anisotropies which are induced by the magnetic field on the
lattice. The second approach is a novel, generalized version of the integral
method, which exploits the independence of the theory on B for asymptotically
large quark masses. Both approaches give consistent results and confirm that
the QCD medium is paramagnetic. Finally, an interesting relation between QCD
paramagnetism, magnetic catalysis of the QCD condensate and the QED
beta-function is pointed out.


title:
Dynamic adjustment: an electoral method for relaxed double
  proportionality

abstract:
  We describe an electoral system for distributing seats in a parliament. It
gives proportionality for the political parties and close to proportionality
for constituencies. The system suggested here is a version of the system used
in Sweden and other Nordic countries with permanent seats in each constituency
and adjustment seats to give proportionality on the national level. In the
national election of 2010 the current Swedish system failed to give
proportionality between parties. We examine here one possible cure for this
unwanted behavior. The main difference compared to the current Swedish system
is that the number of adjustment seats is not fixed, but rather dynamically
determined to be as low as possible and still insure proportionality between
parties.


title: Invariant measures via inverse limits of finite structures

abstract:
  Building on recent results regarding symmetric probabilistic constructions of
countable structures, we provide a method for constructing probability
measures, concentrated on certain classes of countably infinite structures,
that are invariant under all permutations of the underlying set that fix all
constants. These measures are constructed from inverse limits of measures on
certain finite structures. We use this construction to obtain invariant
probability measures concentrated on the classes of countable models of certain
first-order theories, including measures that do not assign positive measure to
the isomorphism class of any single model. We also characterize those
transitive Borel G-spaces admitting a G-invariant probability measure, when G
is an arbitrary countable product of symmetric groups on a countable set.


title: Monadic second-order definable graph orderings

abstract:
  We study the question of whether, for a given class of finite graphs, one can
define, for each graph of the class, a linear ordering in monadic second-order
logic, possibly with the help of monadic parameters. We consider two variants
of monadic second-order logic: one where we can only quantify over sets of
vertices and one where we can also quantify over sets of edges. For several
special cases, we present combinatorial characterisations of when such a linear
ordering is definable. In some cases, for instance for graph classes that omit
a fixed graph as a minor, the presented conditions are necessary and
sufficient; in other cases, they are only necessary. Other graph classes we
consider include complete bipartite graphs, split graphs, chordal graphs, and
cographs. We prove that orderability is decidable for the so called
HR-equational classes of graphs, which are described by equation systems and
generalize the context-free languages.


title: Kronecker Square Roots and The Block vec Matrix

abstract:
  Using the block vec matrix, I give a necessary and sufficient condition for
factorization of a matrix into the Kronecker product of two other matrices. As
a consequence, I obtain an elementary algorithmic procedure to decide whether a
matrix has a square root for the Kronecker product.


title: Observation of Markarian 421 in TeV gamma rays over a 14-year time span

abstract:
  The variability of the blazar Markarian 421 in TeV gamma rays over a 14-year
time period has been explored with the Whipple 10 m telescope. It is shown that
the dynamic range of its flux variations is large and similar to that in
X-rays. A correlation between the X-ray and TeV energy bands is observed during
some bright flares and when the complete data sets are binned on long
timescales. The main database consists of 878.4 hours of observation with the
Whipple telescope, spread over 783 nights. The peak energy response of the
telescope was 400 GeV with 20% uncertainty. This is the largest database of any
TeV-emitting active galactic nucleus (AGN) and hence was used to explore the
variability profile of Markarian 421. The time-averaged flux from Markarian 421
over this period was 0.446$\pm$0.008 Crab flux units. The flux exceeded 10 Crab
flux units on three separate occasions. For the 2000-2001 season the average
flux reached 1.86 Crab units, while in the 1996-1997 season the average flux
was only 0.23 Crab units.


title: Automorphisms of Calabi-Yau threefolds with Picard number three

abstract:
  We prove that the automorphism group of a Calabi-Yau threefold with Picard
number three is either finite, or isomorphic to the infinite cyclic group up to
finite kernel and cokernel.


title:
Scalar Representations in the Light of Electroweak Phase Transition and
  Cold Dark Matter Phenomenology

abstract:
  The extension of the standard model's minimal Higgs sector with an inert
$SU(2)_L$ scalar doublet can provide light dark matter candidate and
simultaneously induce a strong phase transition for explaining Baryogenesis.
There is however no symmetry reasons to prevent the extension using scalars
with higher $SU(2)_L$ representations. By making random scans over the models'
parameters, we show that in the light of electroweak physics constraints,
strong first order electroweak phase transition and the possibility of having
sub-TeV cold dark matter candidate the higher representations are rather
disfavored compared to the inert doublet. This is done by computing generic
perturbativity behavior and impact on electroweak phase transitions of higher
representations in comparison with the inert doublet model. Explicit phase
transition and cold dark matter phenomenology within the context of the inert
triplet and quartet representations are used for detailed illustrations.


title: Self-Completeness and the Generalized Uncertainty Principle

abstract:
  The generalized uncertainty principle discloses a self-complete
characteristic of gravity, namely the possibility of masking any curvature
singularity behind an event horizon as a result of matter compression at the
Planck scale. In this paper we extend the above reasoning in order to overcome
some current limitations to the framework, including the absence of a
consistent metric describing such Planck-scale black holes. We implement a
minimum-size black hole in terms of the extremal configuration of a neutral
non-rotating metric, which we derived by mimicking the effects of the
generalized uncertainty principle via a short scale modified version of
Einstein gravity. In such a way, we find a self-consistent scenario that
reconciles the self-complete character of gravity and the generalized
uncertainty principle.


title: Characteristic cohomology of the infinitesimal period relation

abstract:
  The infinitesimal period relation (also known as Griffiths' transversality)
is the system of partial differential equations constraining variations of
Hodge structure. This paper presents a study of the characteristic cohomology
associated with that system of pde.


title: Metamaterial model of tachyonic dark energy

abstract:
  Dark energy with negative pressure and positive energy density is believed to
be responsible for the accelerated expansion of the universe. Quite a few
theoretical models of dark energy are based on tachyonic fields interacting
with itself and normal (bradyonic) matter. Here we propose an experimental
model of tachyonic dark energy based on hyperbolic metamaterials. Wave equation
describing propagation of extraordinary light inside hyperbolic metamaterials
exhibits 2+1 dimensional Lorentz symmetry. The role of time in the
corresponding effective 3D Minkowski spacetime is played by the spatial
coordinate aligned with the optical axis of the metamaterial. Nonlinear optical
Kerr effect bends this spacetime resulting in effective gravitational force
between extraordinary photons. We demonstrate that this model has a
self-interacting tachyonic sector having negative effective pressure and
positive effective energy density. Moreover, a composite multilayer SiC-Si
hyperbolic metamaterial exhibits closely separated tachyonic and bradyonic
sectors in the long wavelength infrared range. This system may be used as a
laboratory model of inflation and late time acceleration of the universe.


title: Herbrand-Confluence

abstract:
  We consider cut-elimination in the sequent calculus for classical first-order
logic. It is well known that this system, in its most general form, is neither
confluent nor strongly normalizing. In this work we take a coarser (and
mathematically more realistic) look at cut-free proofs. We analyze which
witnesses they choose for which quantifiers, or in other words: we only
consider the Herbrand-disjunction of a cut-free proof. Our main theorem is a
confluence result for a natural class of proofs: all (possibly infinitely many)
normal forms of the non-erasing reduction lead to the same
Herbrand-disjunction.


title: The affine and projective groups are maximal

abstract:
  We show that the groups AGL_n(Q) and PGL_n(Q), seen as closed subgroups of
S_{\infty}, are maximal-closed.


title: GWSDAT - GroundWater Spatiotemporal Data Analysis Tool

abstract:
  Periodic monitoring of groundwater quality at industrial and commercial sites
generates large volumes of spatiotemporal concentration data. Data modelling is
typically restricted to either the analysis of monotonic trends in individual
wells, or independent fitting of spatial concentration distributions (e.g.
Kriging) to separate monitoring time periods. Neither of these techniques
satisfactorily elucidate the interaction between spatial and temporal
components of the data. Potential negative consequences include an incomplete
understanding of groundwater plume dynamics, which can lead to the selection of
inappropriate remedial strategies. The GroundWater Spatiotemporal Data Analysis
Tool (GWSDAT) is a user friendly, open source, decision support tool that has
been developed to address these issues. Uniquely, GWSDAT applies a
spatiotemporal model for a more coherent and smooth interpretation of the
interaction in spatial and time-series components of groundwater solute
concentrations. GWSDAT has been designed to work with standard groundwater
monitoring data sets, and has no special data requirements. Data entry is via a
standardised Microsoft Excel input template. The underlying statistical
modelling and graphical output are generated using R. This paper describes in
detail the various plotting options available and how the graphical user
interface can be used for rapid, rigorous and interactive trend analysis with
facilitated report generation. GWSDAT has been used extensively in the
assessment of soil and groundwater conditions at Shell's downstream assets and
the discussion section describes the benefits of its applied use. These include
rapid interpretation of complex data sets, early identification of new spills,
detection of off-site plume migration and simplified preparation of groundwater
monitoring reports - all of which facilitate expedited risk assessment and
remediation.


title:
Analysis of post wet chemistry heat treatment effects on Nb SRF surface
  resistance

abstract:
  Most of the current research in superconducting radio frequency (SRF)
cavities is focused on ways to reduce the construction and operating cost of
SRF based accelerators as well as on the development of new or improved cavity
processing techniques. The increase in quality factors is the result of the
reduction of the surface resistance of the materials. A recent test on a 1.5
GHz single cell cavity made from ingot niobium of medium purity and heat
treated at 1400 C in a ultra-high vacuum induction furnace resulted in a
residual resistance of about 1nanoohm and a quality factor at 2.0 K increasing
with field up to 5x10^10 at a peak magnetic field of 90 mT. In this
contribution, we present some results on the investigation of the origin of the
extended Q0-increase, obtained by multiple HF rinses, oxypolishing and heat
treatment of all Nb cavities.


title:
Close relationship between superconductivity and the bosonic mode in
  Ba0.6K0.4Fe2As2 and Na(Fe0.975Co0.025)As

abstract:
  Since the discovery of high temperature superconductivity in the iron
pnictides and chalcogenides in early 2008, a central issue has been the
microscopic origin of the superconducting pairing. Although previous
experiments suggest that the pairing may be induced by exchanging the
antiferromagnetic spin fluctuations and the superconducting order parameter has
opposite signs in the electron and hole pockets as predicted by the S+- pairing
model, it remains unclear whether there is a bosonic mode from the tunneling
spectrum which has a close and universal relationship with superconductivity as
well as the spin excitation. In this paper, based on the measurements of
scanning tunneling spectroscopy, we show the clear evidence of a bosonic mode
with the energy identical to that of the neutron spin resonance in two
completely different systems Ba0.6K0.4Fe2As2 and Na(Fe0.975Co0.025)As with
different superconducting transition temperatures. In both samples, the
superconducting coherence peaks and the mode feature vanish simultaneously
inside the vortex core or above Tc, indicating a close relationship between
superconductivity and the bosonic mode. Our data also demonstrate a universal
ratio between the mode energy and superconducting transition temperature, that
is [mode energy]/kBTc ~ 4.3, which underlines the unconventional mechanism of
superconductivity in the iron pnictide superconductors.


title: Quantum random walks on congested lattices

abstract:
  We consider quantum random walks on congested lattices and contrast them to
classical random walks. Congestion is modelled with lattices that contain
static defects which reverse the walker's direction. We implement a dephasing
process after each step which allows us to smoothly interpolate between
classical and quantum random walkers as well as study the effect of dephasing
on the quantum walk. Our key results show that a quantum walker escapes a
finite boundary dramatically faster than a classical walker and that this
advantage remains in the presence of heavily congested lattices. Also, we
observe that a quantum walker is extremely sensitive to our model of dephasing.


title: Charged lepton flavor violation beyond minimal supersymmetry

abstract:
  We discuss charged lepton flavor violation in supersymmetric models with
extended leptonic sectors at low energies. Contrary to the usual high-scale
realizations of the seesaw mechanism, these non-minimal supersymmetric models
have new superfields and/or interactions at the supersymmetric scale. As a
consequence of this, the resulting lepton flavor violating phenomenology may be
very different from that of minimal models.


title: Implementing a simple vectorial bridge with a digital oscilloscope

abstract:
  We show how to exploit instrumentation available in undergraduate student
laboratories to build a simple vectorial bridge. In particular we take
advantage from the possibility to read data from a digital oscilloscope with a
personal computer and describe an algorithm to obtain an accurate evaluation of
the phase difference between two sinusoidal signals. The use of the bridge to
characterize components of a high Q RLC filter is shown to greatly improve the
understanding of results in resonance experiments. Direct evidence of
dielectric losses, of skin currents and of the effect of distributed
capacitance is obtained.


title: Gauge fields beyond perturbation theory

abstract:
  A new formulation of nonabelian gauge theories, introducing new ghost fields
and new symmetry is proposed. This formulation does not suffer from Gribov
ambiguity and allows to quantize nonabelian gauge fields beyond perturbation
theory.


title: Rigidity sensing by stochastic sliding friction

abstract:
  The sliding friction force exerted by stochastic linkers interacting with a
moving filament is calculated. The elastic properties of the substrate on which
the linkers are anchored are shown to strongly influence the friction force. In
some cases, the force is maximal for a finite substrate rigidity. Collective
effects give rise to a dynamical instability resulting in a stick-slip
behaviour, which is substrate-sensitive. The relevance of these results for the
motility of crawling cells powered by an actin retrograde flow is discussed.


title: Correlation Functions and Confinement in Scalar QCD

abstract:
  The complete knowledge of a theory is encoded in its correlation functions.
Thus non-perturbative effects, like confinement in QCD, is necessarily
contained in these correlation functions. As a consequence, a number of
confinement scenarios make predictions for the behavior of these correlation
functions. Non-perturbative methods, like lattice calculations, permit to
calculate the correlation functions and test these predictions. To avoid the
entanglement with chiral symmetry breaking and the costs of full fermion
simulations, here scalar QCD will be used as a role model, as it is expected
that confinement operates in the same way. We present results on both two-point
functions and three-point functions for the case of two colors and two flavors
of scalars, and compare them to the predictions.


title: Partial Wave Analysis of Chiral NN Interactions

abstract:
  We analyze chiral interactions to N2LO on the light of proton-proton and
neutron-proton scattering data published from 1950 till 2013 and discuss
conditions under which the chiral coefficients can be extracted


title: Subband structure of two-dimensional electron gases in SrTiO3

abstract:
  Tunneling between two parallel, two-dimensional electron gases (2DEGs) in a
complex oxide heterostructure containing a large, mobile electron density of ~
3x10^14 cm^-2 is used to probe the subband structure of the 2DEGs.
Temperature-dependent current-voltage measurements are performed on
SrTiO3/GdTiO3/SrTiO3 junctions, where GdTiO3 serves as the tunnel barrier, and
each interface contains a high-density 2DEG. Resonant tunneling features in the
conductance and its derivative occur when subbands on either side of the
barrier align in energy as the applied bias is changed, and are used to analyze
subband energy spacings in the two 2DEGs. We show that the results agree
substantially with recent theoretical predictions for such interfaces.


title: Predicting trend reversals using market instantaneous state

abstract:
  Collective behaviours taking place in financial markets reveal strongly
correlated states especially during a crisis period. A natural hypothesis is
that trend reversals are also driven by mutual influences between the different
stock exchanges. Using a maximum entropy approach, we find coordinated
behaviour during trend reversals dominated by the pairwise component. In
particular, these events are predicted with high significant accuracy by the
ensemble's instantaneous state.


title: On the multi-dimensionel Favard Lemma

abstract:
  We prove that of the creator operators, on the $d$ commuting indeterminates
polynomial algebra, are linearly independent. We further study the connection
between the classical (one dimensional) and the multi-dimensional
($d$-dimensional, $d \geq 1$) Favard Lemmas. Moreover, we investigate the
dependence of the Jacobi sequences on the linear change of basis of
$\mathbb{C}^d$. Finally we prove that the Jacobi sequences associated to the
probability measure product on $\mathbb{R}^d$ are diagonal matrices in the
basis introduced by the tensor product of the orthogonal polynomials of the
factor measures.


title: Distortion and electric field control of band structure of silicene

abstract:
  Density functional theory with local density approximation for exchange and
correlation functional is used to tune the electronic band structure of
silicene monolayer. The cohesive energy of free standing monolayer is
increasing (decreasing) with external electric field (distortion). Electrons in
silicene behave like Dirac fermions, when the bond angle between the Si atoms
is larger than $\sim 102^{0}$. Large distortions destroy the electronic
structure of silicene and silicene is no longer a semi-metallic material, and
the distorted silicene acts like an $n$-doped system. Electric field opens a
band gap around $K$ point in the Brillouin zone, which increases with electric
field. The bond angle between the Si atoms is a key player to determine the
presence or absence of Dirac cones in silicene.


title:
Investigation of MoS2 and Graphene Nanosheets by Magnetic Force
  Microscopy

abstract:
  For the first time, the magnetic force microscopy (MFM) is used to
characterize the mechanically-exfoliated single- and few-layer MoS2 and
graphene nanosheets. By analysis of the phase and amplitude shifts, the
magnetic response of MoS2 and graphene nanosheets exhibits the dependence on
their layer number. However, the solution-processed single-layer MoS2 nanosheet
shows the reverse magnetic signal to the mechanically-exfoliated one, and the
graphene oxide nanosheet has not shown any detectable magnetic signal.
Importantly, graphene and MoS2 flakes become nonmagnetic when they exceed a
certain thickness.


title:
Hybrid quantum magnetism in circuit-QED: from spin-photon waves to
  many-body spectroscopy

abstract:
  We introduce a model of quantum magnetism induced by the non-perturbative
exchange of microwave photons between distant superconducting qubits. By
interconnecting qubits and cavities, we obtain a spin-boson lattice model that
exhibits a quantum phase transition where both qubits and cavities
spontaneously polarise. We present a many-body ansatz that captures this
phenomenon all the way, from a the perturbative dispersive regime where photons
can be traced out, to the non-perturbative ultra-strong coupling regime where
photons must be treated on the same footing as qubits. Our ansatz also
reproduces the low-energy excitations, which are described by hybridised
spin-photon quasiparticles, and can be probed spectroscopically from
transmission experiments in circuit-QED, as shown by simulating a possible
experiment by Matrix-Product-State methods.


title: Long time behavior for a dissipative shallow water model

abstract:
  We consider the two-dimensional shallow water model derived by Levermore and
Sammartino (Nonlinearity 14,2001), describing the motion of an incompressible
fluid, confined in a shallow basin, with varying bottom topography. We
construct the approximate inertial manifolds for the associated dynamical
system and estimate its order. Finally, considering the whole domain R^2 and
under suitable conditions on the time dependent forcing term, we prove the L^2
asymptotic decay of the weak solutions.


title: Influence of long-range interactions on strategy selection in crowd

abstract:
  An order--disorder phase transition is observed for Ising-like systems even
for arbitrarily chosen probabilities of spins flips [K. Malarz et al, Int. J.
Mod. Phys. C 22, 719 (2011)]. For such athermal dynamics one must define
$(z+1)$ spin flips probabilities $w(n)$, where $z$ is a number of the
nearest-neighbours for given regular lattice and $n=0,\cdots,z$ indicates the
number of nearest spins with the same value as the considered spin. Recently,
such dynamics has been successfully applied for the simulation of a cooperative
and competitive strategy selection by pedestrians in crowd [P. Gawro\'nski et
al, Acta Phys. Pol. A 123, 522 (2013)]. For the triangular lattice ($z=6$) and
flips probabilities dependence on a single control parameter $x$ chosen as
$w(0)=1$, $w(1)=3x$, $w(2)=2x$, $w(3)=x$, $w(4)=x/2$, $w(5)=x/4$, $w(6)=x/6$
the ordered phase (where most of pedestrians adopt the same strategy) vanishes
for $x>x_C\approx 0.429$. In order to introduce long-range interactions between
pedestrians the bonds of triangular lattice are randomly rewired with the
probability $p$. The amount of rewired bonds can be interpreted as the
probability of communicating by mobile phones. The critical value of control
parameter $x_C$ increases monotonically with the number of rewired links
$M=pzN/2$ from $x_C(p=0)\approx 0.429$ to $x_C(p=1)\approx 0.81$.


title:
Bayesian Regression Analysis of Data with Random Effects Covariates from
  Nonlinear Longitudinal Measurements

abstract:
  Joint models for a wide class of response variables and longitudinal
measurements consist on a mixed-effects model to fit longitudinal trajectories
whose random effects enter as covariates in a generalized linear model for the
primary response. They provide a useful way to asses association between these
two kinds of data, which in clinical studies are often collected jointly on a
series of individuals and may help understanding, for instance, the mechanisms
of recovery of a certain disease or the efficacy of a given therapy. The most
common joint model in this framework is based on a linear mixed model for the
longitudinal data. However, for complex datasets the linearity assumption may
be too restrictive. Some works have considered generalizing this setting with
the use of a nonlinear mixed-effects model for the longitudinal trajectories
but the proposed estimation procedures based on likelihood approximations have
been shown De la Cruz et al. (2011) to exhibit some computational efficiency
problems. In this article we propose an MCMC-based estimation procedure in the
joint model with a nonlinear mixed-effects model for the longitudinal data and
a generalized linear model for the primary response. Moreover, we consider that
the errors in the longitudinal model may be correlated. We apply our method to
the analysis of hormone levels measured at the early stages of pregnancy that
can be used to predict normal versus abnormal pregnancy outcomes. We also
conduct a simulation study to asses the importance of modelling correlated
errors and quantify the consequences of model misspecification.


title: On the Origin of the 6.4 keV Line in the Galactic Center Region

abstract:
  We analyse the 6.4 keV iron line component produced in the Galactic Center
(GC) region by cosmic rays in dense molecular clouds (MCs) and in the diffuse
molecular gas. We showed that this component, in principle, can be seen in
several years in the direction of the cloud Srg B2. If this emission is
produced by low energy CRs which ionize the interstellar molecular gas the
intensity of the line is quite small, < 1%. However, we cannot exclude that
local sources of CRs or X-ray photons nearby the cloud may provide much higher
intensity of the line from there. Production of the line emission from
molecular clouds depends strongly on processes of CR penetration into them. We
show that turbulent motions of neutral gas may generate strong magnetic
fluctuations in the clouds which prevent free penetration of CRs into the
clouds from outside. We provide a special analysis of the line production by
high energy electrons. We concluded that these electrons hardly provide the
diffuse 6.4 keV line emission from the GC because their density is depleted by
ionization losses. We do not exclude that local sources of electrons may
provide an excesses of the 6.4 keV line emission in some molecular clouds and
even reproduce a relatively short time variations of the iron line emission.
However, we doubt whether a single electron source provides the simultaneous
short time variability of the iron line emission from clouds which are distant
from each other on hundred pc as observed for the GC clouds. An alternative
speculation is that local electron sources could also provide the necessary
effect of the line variations in different clouds that are seen simultaneously
by chance that seems, however, very unlikely.


title: Differential rotation in solar-like stars from global simulations

abstract:
  To explore the physics of large-scale flows in solar-like stars, we perform
3D anelastic simulations of rotating convection for global models with
stratification resembling the solar interior. The numerical method is based on
an implicit large-eddy simulation approach designed to capture effects from
non-resolved small scales. We obtain two regimes of differential rotation, with
equatorial zonal flows accelerated either in the direction of rotation
(solar-like) or in the opposite direction (anti-solar). While the models with
the solar-like differential rotation tend to produce multiple cells of
meridional circulation, the models with anti-solar differential rotation result
in only one or two meridional cells. Our simulations indicate that the rotation
and large-scale flow patterns critically depend on the ratio between buoyancy
and Coriolis forces. By including a subadiabatic layer at the bottom of the
domain, corresponding to the stratification of a radiative zone, we reproduce a
layer of strong radial shear similar to the solar tachocline. Similarly,
enhanced superadiabaticity at the top results in a near-surface shear layer
located mainly at lower latitudes. The models reveal a latitudinal entropy
gradient localized at the base of the convection zone and in the stable region,
which however does not propagate across the convection zone. In consequence,
baroclinicity effects remain small and the rotation iso-contours align in
cylinders along the rotation axis. Our results confirm the alignment of large
convective cells along the rotation axis in the deep convection zone, and
suggest that such "banana-cell" pattern can be hidden beneath the
supergranulation layer.


title: Almost isoperimetric subsets of the discrete cube

abstract:
  We show that a set $A \subset \{0,1\}^{n}$ with edge-boundary of size at most
$|A| (\log_{2}(2^{n}/|A|) + \epsilon)$ can be made into a subcube by at most
$(2 \epsilon/\log_{2}(1/\epsilon))|A|$ additions and deletions, provided
$\epsilon$ is less than an absolute constant.
  We deduce that if $A \subset \{0,1\}^{n}$ has size $2^{t}$ for some $t \in
\mathbb{N}$, and cannot be made into a subcube by fewer than $\delta |A|$
additions and deletions, then its edge-boundary has size at least $|A|
\log_{2}(2^{n}/|A|) + |A| \delta \log_{2}(1/\delta) = 2^{t}(n-t+\delta
\log_{2}(1/\delta))$, provided $\delta$ is less than an absolute constant. This
is sharp whenever $\delta = 1/2^{j}$ for some $j \in \{1,2,\ldots,t\}$.


title:
Detection, spectroscopy and state preparation of a single praseodymium
  ion in a crystal

abstract:
  Solid-state emitters with atom-like optical and magnetic transitions are
highly desirable for efficient and scalable quantum state engineering and
information processing. Quantum dots, color centers and impurities embedded in
inorganic hosts have attracted a great deal of attention in this context, but
influences from the matrix continue to pose challenges on the degree of
attainable coherence in each system. We report on a new solid-state platform
based on the optical detection of single praseodymium ions via 4f intrashell
transitions, which are well shielded from their surroundings. By combining
cryogenic high-resolution laser spectroscopy with fluorescence microscopy, we
were able to spectrally select and spatially resolve individual ions. In
addition to elaborating on the essential experimental steps for achieving this
long-sought goal, we demonstrate state preparation and read out of the three
ground-state hyperfine levels, which are known to have lifetimes of the order
of hundred seconds.


title:
Dark photon searches using displaced vertices at low energy e+e-
  colliders

abstract:
  The existence of a new, photon-like, massive particle, the gamma' or dark
photon, is postulated in several extensions of the Standard Model. These models
are often advocated to explain some recent puzzling astrophysical observations,
as well as to solve the unsofar unexplained deviation between the measured and
calculated values of the muon anomaly. Dark photons can be produced at e+e-
colliders both in continuum events and in vector meson transitions and can
eventually decay into an electron-positron pair. For a proper choice of the
parameters of the theory, a $\gamma'$ can have a relatively long lifetime and
can therefore be observed as an e+e- vertex well separated by the primary
interaction point. This case is discussed in reference to very high luminosity
e+e- colliders either in construction or under study in several laboratories in
the world. It is shown that a search strategy based on the detection of
displaced vertices can be in principle very effective in covering a rather wide
and to date unexplored region of the theoretical parameters space.


title: Expansions of MSO by cardinality relations

abstract:
  We study expansions of the Weak Monadic Second Order theory of (N,<) by
cardinality relations, which are predicates R(X1,...,Xn) whose truth value
depends only on the cardinality of the sets X1, ...,Xn. We first provide a
(definable) criterion for definability of a cardinality relation in (N,<), and
use it to prove that for every cardinality relation R which is not definable in
(N,<), there exists a unary cardinality relation which is definable in (N,<,R)
and not in (N,<). These results resemble Muchnik and Michaux-Villemaire
theorems for Presburger Arithmetic. We prove then that + and x are definable in
(N,<,R) for every cardinality relation R which is not definable in (N,<). This
implies undecidability of the WMSO theory of (N,<,R). We also consider the
related satisfiability problem for the class of finite orderings, namely the
question whether an MSO sentence in the language {<,R} admits a finite model M
where < is interpreted as a linear ordering, and R as the restriction of some
(fixed) cardinality relation to the domain of M. We prove that this problem is
undecidable for every cardinality relation R which is not definable in (N,<).


title: Search for heavy resonances decaying to top quarks

abstract:
  In many models of physics beyond the Standard Model the coupling of new
states to third generation quarks is enhanced. A review is presented of
searches by the CMS collaboration for heavy particles decaying to final states
involving top quarks. This includes searches for heavy gauge bosons and excited
states. Several final states originating from the top quark decays are
considered and the event reconstruction is optimised accordingly. The analyses
presented use data collected with the CMS experiment during the year 2012 at
the LHC, in proton-proton collisions at a centre-of-mass energy of 8 TeV.


title: Phenomenology of the Watcher measure in the Bousso-Polchinski landscape

abstract:
  We investigate the phenomenology of the "Watcher" measure in the
Bousso-Polchinski landscape. We study a small toy landscape analytically. The
results are sufficient to allow us to extrapolate "watcher" phenomenology to
much larger landscapes. We compare our results to other measures which have
been applied to BP landscapes containing googles of vacua. Under certain well
motivated conditions, watcher phenomenology coincides with the causal patch
prescription, but not Linde's volume weighted measure.


title:
Dynamics of popstar record sales on phonographic market -- stochastic
  model

abstract:
  We investigate weekly record sales of the world's most popular 30 artists
(2003-2013). Time series of sales have non-trivial kind of memory
(anticorrelations, strong seasonality and constant autocorrelation decay within
120 weeks). Amount of artists record sales are usually the highest in the first
week after premiere of their brand new records and then decrease to fluctuate
around zero till next album release. We model such a behavior by discrete
mean-reverting geometric jump diffusion (MRGJD) and Markov regime switching
mechanism (MRS) between the base and the promotion regimes. We can built up the
evidence through such a toy model that quantifies linear and nonlinear
dynamical components (with stationary and nonstationary parameters set), and
measure local divergence of the system with collective behavior phenomena. We
find special kind of disagreement between model and data for Christmas time due
to unusual shopping behavior. Analogies to earthquakes, product life-cycles,
and energy markets will also be discussed.


title: Claw-free t-perfect graphs can be recognised in polynomial time

abstract:
  A graph is called t-perfect if its stable set polytope is defined by
non-negativity, edge and odd-cycle inequalities. We show that it can be decided
in polynomial time whether a given claw-free graph is t-perfect.


title:
SmartLoc: Sensing Landmarks Silently for Smartphone Based Metropolitan
  Localization

abstract:
  We present \emph{SmartLoc}, a localization system to estimate the location
and the traveling distance by leveraging the lower-power inertial sensors
embedded in smartphones as a supplementary to GPS. To minimize the negative
impact of sensor noises, \emph{SmartLoc} exploits the intermittent strong GPS
signals and uses the linear regression to build a prediction model which is
based on the trace estimated from inertial sensors and the one computed from
the GPS. Furthermore, we utilize landmarks (e.g., bridge, traffic lights)
detected automatically and special driving patterns (e.g., turning, uphill, and
downhill) from inertial sensory data to improve the localization accuracy when
the GPS signal is weak. Our evaluations of \emph{SmartLoc} in the city
demonstrates its technique viability and significant localization accuracy
improvement compared with GPS and other approaches: the error is approximately
20m for 90% of time while the known mean error of GPS is 42.22m.


title: A note on dark matter and dark energy

abstract:
  Since the geometry of our universe seems to depend very little on baryonic
matter, we consider a variational principle involving only dark matter and dark
energy which in addition make them depend on each other. There are no
adjustable parameters or scalar fields with appropriate equations of state. No
quintessence. For a pressure-less, three-flat FRW model, the cosmological
"constant" is now a function of time, positive by definition and always small.
Its time derivative or rather its associated parameter w is always negative and
close to minus one. The most interesting point is that the age of the universe
and w itself are correlated. Moreover, this rather unsophisticated model
provides a very limited range for both these quantities and results are in
surprising agreement with observed values. The problem of vacuum energy remains
what it was; the problem of coincidence is significantly less annoying.