title: Nontrivial t-Designs over Finite Fields Exist for All t

abstract:
  A $t$-$(n,k,\lambda)$ design over $\F_q$ is a collection of $k$-dimensional
subspaces of $\F_q^n$, called blocks, such that each $t$-dimensional subspace
of $\F_q^n$ is contained in exactly $\lambda$ blocks. Such $t$-designs over
$\F_q$ are the $q$-analogs of conventional combinatorial designs. Nontrivial
$t$-$(n,k,\lambda)$ designs over $\F_q$ are currently known to exist only for
$t \leq 3$. Herein, we prove that simple (meaning, without repeated blocks)
nontrivial $t$-$(n,k,\lambda)$ designs over $\F_q$ exist for all $t$ and $q$,
provided that $k > 12t$ and $n$ is sufficiently large. This may be regarded as
a $q$-analog of the celebrated Teirlinck theorem for combinatorial designs.


title:
Uncertainty Principle for the Clifford Geometric Algebra Cl(3,0) based
  on Clifford Fourier Transform

abstract:
  In the field of applied mathematics the Fourier transform has developed into
an important tool. It is a powerful method for solving partial differential
equations. The Fourier transform provides also a technique for signal analysis
where the signal from the original domain is transformed to the spectral or
frequency domain. In the frequency domain many characteristics of the signal
are revealed. With these facts in mind, we extend the Fourier transform in
geometric algebra. We explicitly show detailed properties of the real Clifford
geometric algebra Fourier transform (CFT), which we subsequently use to define
and prove the uncertainty principle for Cl(3,0) multivector functions.


title:
Molecular Clouds Toward the Super Star Cluster NGC3603; Possible
  Evidence for a Cloud-Cloud Collision in Triggering the Cluster Formation

abstract:
  We present new large field observations of molecular clouds with NANTEN2
toward the super star cluster NGC3603 in the transitions 12CO(J=2-1, J=1-0) and
13CO(J=2-1, J=1-0). We suggest that two molecular clouds at 13 km s-1 and 28 km
s-1 are associated with NGC3603 as evidenced by higher temperatures toward the
H II region as well as morphological correspondence. The mass of the clouds is
too small to gravitationally bind them, given their relative motion of ~20 km
s-1. We suggest that the two clouds collided with each other a Myr ago to
trigger the formation of the super star cluster. This scenario is able to
explain the origin of the highest mass stellar population in the cluster which
is as young as a Myr and is segregated within the central sub-pc of the
cluster. This is the second super star cluster along side Westerlund2 where
formation may have been triggered by a cloud-cloud collision.


title:
A framework for (under)specifying dependency syntax without overloading
  annotators

abstract:
  We introduce a framework for lightweight dependency syntax annotation. Our
formalism builds upon the typical representation for unlabeled dependencies,
permitting a simple notation and annotation workflow. Moreover, the formalism
encourages annotators to underspecify parts of the syntax if doing so would
streamline the annotation process. We demonstrate the efficacy of this
annotation on three languages and develop algorithms to evaluate and compare
underspecified annotations.


title:
Two-sided Clifford Fourier transform with two square roots of -1 in
  Cl(p,q)

abstract:
  We generalize quaternion and Clifford Fourier transforms to general two-sided
Clifford Fourier transforms (CFT), and study their properties (from linearity
to convolution). Two general \textit{multivector square roots} $\in \cl{p,q}$
\textit{of} -1 are used to split multivector signals, and to construct the left
and right CFT kernel factors.
  Keywords: Clifford Fourier transform, Clifford algebra, signal processing,
square roots of -1 .


title:
Whitney's theorem for local anisotropic polynomial L_p-approximation,
  0<p<1

abstract:
  Dinh D\~ung and T. Ullrich have proven a multivariate Whitney's theorem for
the local anisotropic polynomial approximation in $L_p(Q)$ for $1 \le p \le
\infty$, where $Q$ is a $d$-parallelepiped in $\RR^d$ with sides parallel to
the coordinate axes. They considered the error of best approximation of a
function $f$ by algebraic polynomials of fixed degree at most $r_i - 1$ in
variable $x_i,\ i=1,...,d$. The convergence rate of the approximation error
when the size of $Q$ going to 0 is characterized by a so-called total mixed
modulus of smoothness. The method of proof used by these authors is not
suitable to the case $0 <p<1$. In the present paper, by a different method we
proved this theorem for $0< p \le \infty$.


title:
Predicting Risk-of-Readmission for Congestive Heart Failure Patients: A
  Multi-Layer Approach

abstract:
  Mitigating risk-of-readmission of Congestive Heart Failure (CHF) patients
within 30 days of discharge is important because such readmissions are not only
expensive but also critical indicator of provider care and quality of
treatment. Accurately predicting the risk-of-readmission may allow hospitals to
identify high-risk patients and eventually improve quality of care by
identifying factors that contribute to such readmissions in many scenarios. In
this paper, we investigate the problem of predicting risk-of-readmission as a
supervised learning problem, using a multi-layer classification approach.
Earlier contributions inadequately attempted to assess a risk value for 30 day
readmission by building a direct predictive model as opposed to our approach.
We first split the problem into various stages, (a) at risk in general (b) risk
within 60 days (c) risk within 30 days, and then build suitable classifiers for
each stage, thereby increasing the ability to accurately predict the risk using
multiple layers of decision. The advantage of our approach is that we can use
different classification models for the subtasks that are more suited for the
respective problems. Moreover, each of the subtasks can be solved using
different features and training data leading to a highly confident diagnosis or
risk compared to a one-shot single layer approach. An experimental evaluation
on actual hospital patient record data from Multicare Health Systems shows that
our model is significantly better at predicting risk-of-readmission of CHF
patients within 30 days after discharge compared to prior attempts.


title:
Representation of Crystallographic Subperiodic Groups in Clifford's
  Geometric Algebra

abstract:
  This paper explains how, following the representation of 3D crystallographic
space groups in Clifford's geometric algebra, it is further possible to
similarly represent the 162 so called subperiodic groups of crystallography in
Clifford's geometric algebra. A new compact geometric algebra group
representation symbol is constructed, which allows to read off the complete set
of geometric algebra generators. For clarity moreover the chosen generators are
stated explicitly. The group symbols are based on the representation of point
groups in geometric algebra by versors (Clifford monomials, Lipschitz
elements).
  Keywords: Subperiodic groups, Clifford's geometric algebra, versor
representation, frieze groups, rod groups, layer groups .


title:
Feature-Gathering Dependency-Based Software Clustering Using Dedication
  and Modularity

abstract:
  Software clustering is one of the important techniques to comprehend software
systems. However, presented techniques to date require human interactions to
refine clustering results. In this paper, we proposed a novel dependency-based
software clustering algorithm, SArF. SArF has two characteristics. First, SArF
eliminates the need of the omnipresent-module-removing step which requires
human interactions. Second, the objective of SArF is to gather relevant
software features or functionalities into a cluster. To achieve them, we
defined the Dedication score to infer the importance of dependencies and
utilized Modularity Maximization to cluster weighted directed graphs. Two case
studies and extensive comparative evaluations using open source and industrial
systems show that SArF could successfully decompose the systems fitting to the
authoritative decompositions from a feature viewpoint without any tailored
setups and that SArF was superior to existing dependency-based software
clustering studies. Besides, the case studies show that there exist measurable
authoritativeness limits and that SArF nearly reached the limits.


title: A Babu\v{s}ka-Aziz type proof of the circumradius condition

abstract:
  In this paper the error of polynomial interpolation of degree 1 on triangles
is considered. The circumradius condition, which is more general than the
maximum angle condition, is explained and proved by the technique given by
Babu\v{s}ka-Aziz.


title:
Weak decay constant of neutral pions in a hot and magnetized quark
  matter

abstract:
  The directional weak decay constants of neutral pions are determined at
finite temperature T, chemical potential \mu and in the presence of a constant
magnetic field B. To do this, we first derive the energy dispersion relation of
neutral pions from the corresponding effective action of a two-flavor, hot and
magnetized Nambu--Jona-Lasinio model. Using this dispersion relation, including
nontrivial directional refraction indices, we then generalize the PCAC relation
of neutral pions and derive the Goldberger-Treiman (GT) as well as the
Gell--Mann-Oakes-Renner (GOR) relations consisting of directional quark-pion
coupling constant g_{qq\pi^{0}}^{(\mu)} and weak decay constant
f_{\pi^{0}}^{(\mu)} of neutral pions. The temperature dependence of
g_{qq\pi^{0}}^{(\mu)} and f_{\pi^{0}}^{(\mu)}, are then determined for fixed
chemical potential and various constant background magnetic fields. The GT and
GOR relations are also verified at finite T,\mu and eB. It is shown that,
because of the explicit breaking of the Lorentz invariance by the magnetic
field, the directional quark-pion coupling and decay constants of neutral pions
in the longitudinal and transverse directions with respect to the direction of
the external magnetic field are different, i.e. g_{qq\pi^{0}}^{\|}\neq
g_{qq\pi^{0}}^{\perp} and f_{\pi^{0}}^{\|}\neq f_{\pi^{0}}^{\perp}. As it turns
out, for fixed T,\mu and B, g_{qq\pi^{0}}^{\|}> g_{qq\pi^{0}}^{\perp} and
f_{\pi^{0}}^{\|}< f_{\pi^{0}}^{\perp}.


title:
A recipe for Hamiltonian of system-environment coupling applicable to
  ultrastrong light-matter interaction regime

abstract:
  When the light interacts with matters in a lossy cavity, in the standard
cavity quantum electrodynamics, the dissipation of cavity fields is
characterized simply by the strengths of the two couplings: the light-matter
interaction and the system-environment coupling through the cavity mirror.
However, in the ultrastrong light-matter interaction regime, the dissipation
depends also on whether the two couplings are mediated by the electric field or
the magnetic one (capacitive or inductive in superconducting circuits). Even if
we know correctly the microscopic mechanism (Lagrangian) of the
system-environment coupling, the coupling Hamiltonian itself is in principle
modified due to the ultrastrong interaction in the cavity. In this paper, we
show a recipe for deriving a general expression of the Hamiltonian of the
system-environment coupling, which is applicable even in the ultrastrong
light-matter interaction regime in the good-cavity and independent-transition
limit.


title:
Discriminative extended canonical correlation analysis for pattern set
  matching

abstract:
  In this paper we address the problem of matching sets of vectors embedded in
the same input space. We propose an approach which is motivated by canonical
correlation analysis (CCA), a statistical technique which has proven successful
in a wide variety of pattern recognition problems. Like CCA when applied to the
matching of sets, our extended canonical correlation analysis (E-CCA) aims to
extract the most similar modes of variability within two sets. Our first major
contribution is the formulation of a principled framework for robust inference
of such modes from data in the presence of uncertainty associated with noise
and sampling randomness. E-CCA retains the efficiency and closed form
computability of CCA, but unlike it, does not possess free parameters which
cannot be inferred directly from data (inherent data dimensionality, and the
number of canonical correlations used for set similarity computation). Our
second major contribution is to show that in contrast to CCA, E-CCA is readily
adapted to match sets in a discriminative learning scheme which we call
discriminative extended canonical correlation analysis (DE-CCA). Theoretical
contributions of this paper are followed by an empirical evaluation of its
premises on the task of face recognition from sets of rasterized appearance
images. The results demonstrate that our approach, E-CCA, already outperforms
both CCA and its quasi-discriminative counterpart constrained CCA (C-CCA), for
all values of their free parameters. An even greater improvement is achieved
with the discriminative variant, DE-CCA.


title:
Secrecy Rates in the Broadcast Channel with Confidential Messages and
  External Eavesdroppers

abstract:
  In this paper, we consider the broadcast channel with confidential messages
and external eavesdroppers (BCCE), where a multi-antenna base station
simultaneously communicates to multiple potentially malicious users, in the
presence of randomly located external eavesdroppers. Using the proposed model,
we study the secrecy rates achievable by regularized channel inversion (RCI)
precoding by performing a large-system analysis that combines tools from
stochastic geometry and random matrix theory. We obtain explicit expressions
for the probability of secrecy outage and an upper bound on the rate loss due
to the presence of external eavesdroppers. We show that both these quantities
scale as $\frac{\lambda_e}{\sqrt{N}}$, where $N$ is the number of transmit
antennas and $\lambda_e$ is the density of external eavesdroppers, irrespective
of their collusion strategy. Furthermore, we derive a practical rule for the
choice of the regularization parameter, which is agnostic of channel state
information and location of eavesdroppers, and yet provides close to optimal
performance.


title: Discriminative k-means clustering

abstract:
  The k-means algorithm is a partitional clustering method. Over 60 years old,
it has been successfully used for a variety of problems. The popularity of
k-means is in large part a consequence of its simplicity and efficiency. In
this paper we are inspired by these appealing properties of k-means in the
development of a clustering algorithm which accepts the notion of "positively"
and "negatively" labelled data. The goal is to discover the cluster structure
of both positive and negative data in a manner which allows for the
discrimination between the two sets. The usefulness of this idea is
demonstrated practically on the problem of face recognition, where the task of
learning the scope of a person's appearance should be done in a manner which
allows this face to be differentiated from others.


title:
On the quantum-field description of many-particle Bose systems with
  spontaneously broken symmetry

abstract:
  A quantum-field approach to studying the Bose systems at finite temperatures
and in states with spontaneously broken symmetry, in particular in a superfluid
state, is proposed. A generalized model of a self-consistent field (SCF) for
spatially inhomogeneous many-particle Bose systems is used as the initial
approximation. A perturbation theory has been developed, and a diagram
technique for temperature Green's functions (GFs) has been constructed. The
Dyson's equations joining the eigenenergy and vertex functions have been
deduced.


title: On the zone of the boundary of a convex body

abstract:
  We consider an arrangement $\A$ of $n$ hyperplanes in $\R^d$ and the zone
$\Z$ in $\A$ of the boundary of an arbitrary convex set in $\R^d$ in such an
arrangement. We show that, whereas the combinatorial complexity of $\Z$ is
known only to be $O<n^{d-1}\log n>$ \cite{APS}, the outer part of the zone has
complexity $O<n^{d-1}>$ (without the logarithmic factor). Whether this bound
also holds for the complexity of the inner part of the zone is still an open
question (even for $d=2$).


title: From Newton's cradle to the discrete p-Schr\"odinger equation

abstract:
  We investigate the dynamics of a chain of oscillators coupled by
fully-nonlinear interaction potentials. This class of models includes Newton's
cradle with Hertzian contact interactions between neighbors. By means of
multiple-scale analysis, we give a rigorous asymptotic description of small
amplitude solutions over large times. The envelope equation leading to
approximate solutions is a discrete p-Schr\"odinger equation. Our results
include the existence of long-lived breather solutions to the original model.
For a large class of localized initial conditions, we also estimate the maximal
decay of small amplitude solutions over long times.


title:
Integral field spectroscopy of supernova explosion sites: constraining
  mass and metallicity of the progenitors -- II. Type II-P and II-L supernovae

abstract:
  Thirteen explosion sites of type II-P and II-L supernovae in nearby galaxies
have been observed using integral field spectroscopy, enabling both spatial and
spectral study of the explosion sites. We used the properties of the parent
stellar population of the coeval supernova progenitor star to derive its
metallicity and initial mass (c.f. Paper I). The spectrum of the parent stellar
population yields the estimates of metallicity via strong-line method, and age
via comparison with simple stellar population (SSP) models. These metallicity
and age parameters are adopted for the progenitor star. Age, or lifetime of the
star, was used to derive initial (ZAMS) mass of the star by comparing with
stellar evolution models. With this technique, we were able to determine
metallicity and initial mass of the SN progenitors in our sample. Our result
indicates that some type-II supernova progenitors may have been stars with mass
comparable to SN Ib/c progenitors.


title:
Numerical study of a slip-link model for polymer melts and
  nanocomposites

abstract:
  We present a numerical study of the slip link model introduced by Likhtman
for describing the dy- namics of dense polymer melts. After reviewing the
technical aspects associated with the implemen- tation of the model, we extend
previous work in several directions. The dependence of the relaxation modulus
with the slip link density and the slip link stiffness is reported. Then the
nonlinear rheolog- ical properties of the model, for a particular set of
parameters, are explored. Finally, we introduce excluded volume interactions in
a mean field such as manner in order to describe inhomogeneous systems, and we
apply this description to a simple nanocomposite model. With this extension,
the slip link model appears as a simple and generic model of a polymer melt,
that can be used as an alternative to molecular dynamics for coarse grained
simulations of complex polymeric systems.


title: Asymptotic Analysis and Random Sampling of Digitally Convex Polyominoes

abstract:
  Recent work of Brlek \textit{et al.} gives a characterization of digitally
convex polyominoes using combinatorics on words. From this work, we derive a
combinatorial symbolic description of digitally convex polyominoes and use it
to analyze their limit properties and build a uniform sampler. Experimentally,
our sampler shows a limit shape for large digitally convex polyominoes.


title: Distributed Decision-Making over Adaptive Networks

abstract:
  In distributed processing, agents generally collect data generated by the
same underlying unknown model (represented by a vector of parameters) and then
solve an estimation or inference task cooperatively. In this paper, we consider
the situation in which the data observed by the agents may have risen from two
different models. Agents do not know beforehand which model accounts for their
data and the data of their neighbors. The objective for the network is for all
agents to reach agreement on which model to track and to estimate this model
cooperatively. In these situations, where agents are subject to data from
unknown different sources, conventional distributed estimation strategies would
lead to biased estimates relative to any of the underlying models. We first
show how to modify existing strategies to guarantee unbiasedness. We then
develop a classification scheme for the agents to identify the models that
generated the data, and propose a procedure by which the entire network can be
made to converge towards the same model through a collaborative decision-making
process. The resulting algorithm is applied to model fish foraging behavior in
the presence of two food sources.


title:
Effect of dot size on exciton binding energy and electron-hole
  recombination probability in CdSe quantum dots

abstract:
  Exciton binding energy and electron-hole recombination probability are
presented as the two important metrics for investigating effect of dot size on
electron-hole interaction in CdSe quantum dots. Direct computation of
electron-hole recombination probability is challenging because it requires an
accurate mathematical description of electron-hole wavefunction in the
neighborhood of the electron-hole coalescence point. In this work, we address
this challenge by solving the electron-hole Schrodinger equation using the
electron-hole explicitly correlated Hartree-Fock (eh-XCHF) method. The
calculations were performed for a series of CdSe clusters ranging from
$\mathrm{Cd}_{20}\mathrm{Se}_{19}$ to $\mathrm{Cd}_{74608}\mathrm{Se}_{74837}$
that correspond to dot diameter range of 1-20 nm. The calculated exciton
binding energies and electron-hole recombination probabilities were found to
decrease with increasing dot size. Both of these quantities were found to scale
as $D_\mathrm{dot}^{-n}$ with respect to the dot diameter D. One of the key
insights from this study is that the electron-hole recombination probability
decreases at a much faster rate than the exciton binding energy as a function
of dot size. It was found that an increase in the dot size by a factor of 16.1,
resulted in a decrease in the exciton binding energy and electron-hole
recombination probability by a factor of 14.4 and $5.5\times10^{6}$,
respectively.


title: Visible Spectroscopic Observations of Near-Earth Object 2012 DA14

abstract:
  We present visible spectroscopic observations of a near-earth object (NEO)
2012 DA14. The asteroid 2012 DA14 came close to the surface of the Earth on
February 15, 2013 at a distance of 27,700 km. Its estimated diameter is around
45 m. The physical properties of such a small asteroid have not yet been well
determined. The close encounter is a good opportunity to conduct a variety of
observations. The purpose of this paper is to deduce the taxonomy of 2012 DA14
by visible spectroscopic observations using the 0.4 m f/10 telescope at the
Fujii Kurosaki Observatory. We conclude that the taxonomy of 2012 DA14 is an
L-type in the visible wavelength region. In addition, we refer to the
availability of a small, accessible telescope for NEOs smaller than 100 m.


title: Topography influence on the Lake equations in bounded domains

abstract:
  We investigate the influence of the topography on the lake equations which
describe the two-dimensional horizontal velocity of a three-dimensional
incompressible flow. We show that the lake equations are structurally stable
under Hausdorff approximations of the fluid domain and $L^p$ perturbations of
the depth. As a byproduct, we obtain the existence of a weak solution to the
lake equations in the case of singular domains and rough bottoms. Our result
thus extends earlier works by Bresch and M\'etivier treating the lake equations
with a fixed topography and by G\'erard-Varet and Lacave treating the Euler
equations in singular domains.


title: Composable security of measuring-Alice blind quantum computation

abstract:
  Blind quantum computing [A. Broadbent, J. Fitzsimons, and E. Kashefi,
Proceedings of the 50th Annual IEEE Symposium on Foundations of Computer
Science 517 (2009)] is a secure cloud quantum computing protocol which enables
a client (who does not have enough quantum technology at her disposal) to
delegate her quantum computation to a server (who has a universal quantum
computer) without leaking any relevant information to the server. In [T.
Morimae and K. Fujii, Phys. Rev. A {\bf87}, 050301(R) (2013)], a new blind
quantum computing protocol, so called the measuring-Alice protocol, was
proposed. This protocol offers several advantages over previous protocols, such
as the device-independent security, less demanding requirements for the client,
and a simpler and stronger security based on the no-signaling principle. In
this paper, we show composable security of the measuring-Alice protocol by
using the formalism of the constructive cryptography [U. Maurer, Proceedings of
Theory of Security and Applications, TOSCA 2011, pages 33-56. Springer (2011)].
The above advantages of measuring-Alice protocol enable more intuitive and
transparent proofs for the composable security.


title:
Minimal forbidden induced subgraphs of graphs of bounded clique-width
  and bounded linear clique-width

abstract:
  In the study of full bubble model graphs of bounded clique-width and bounded
linear clique-width, we determined complete sets of forbidden induced
subgraphs, that are minimal in the class of full bubble model graphs. In this
note, we show that (almost all of) these graphs are minimal in the class of all
graphs. As a corollary, we can give sets of minimal forbidden induced subgraphs
for graphs of bounded clique-width and for graphs of bounded linear
clique-width for arbitrary bounds.


title:
Carbon nanotubes in almost homogeneous transverse magnetic field:
  exactly solvable model

abstract:
  A class of exactly solvable models describing carbon nanotubes in the
presence of an external inhomogeneous magnetic field is considered. The
framework of the continuum approximation is employed, where the motion of the
charge carriers is governed by the Dirac- Weyl equation. The explicit solution
of a particular example is provided. It is shown that these models possess
nontrivial integrals of motion that establish N = 2 nonlinear supersymmetry in
case of metallic and maximally semiconducting nanotubes. Remarkable stability
of energy levels with respect to small fluctuations of longitudinal momentum is
demonstrated

categories: cond-mat.mes-hall hep-th math-ph math.MP quant-ph


title:
Consistency of the maximum likelihood estimate for Non-homogeneous
  Markov-switching models

abstract:
  Many nonlinear time series models have been proposed in the last decades.
Among them, the models with regime switchings provide a class of versatile and
interpretable models which have received a particular attention in the
literature. In this paper, we consider a large family of such models which
generalize the well known Markov-switching AutoRegressive (MS-AR) by allowing
non-homogeneous switching and encompass Threshold AutoRegressive (TAR) models.
We prove various theoretical results related to the stability of these models
and the asymptotic properties of the Maximum Likelihood Estimates (MLE). The
ability of the model to catch complex nonlinearities is then illustrated on
various time series.


title:
Classical integrability for beta-ensembles and general Fokker-Planck
  equations

abstract:
  Beta-ensembles of random matrices are naturally considered as quantum
integrable systems, in particular, due to their relation with conformal field
theory, and more recently appeared connection with quantized Painlev\'e
Hamiltonians. Here we demonstrate that, at least for {\it even integer} beta,
these systems are classically integrable, e.g. there are Lax pairs associated
with them, which we explicitly construct. To come to the result, we show that a
solution of every Fokker-Planck equation in one space (and one time) dimensions
can be considered as a component of an eigenvector of a Lax pair. The explicit
finding of the Lax pair depends on finding a solution of a governing system --
a closed system of two nonlinear PDEs of hydrodynamic type. This result
suggests that there must be a solution for all values of beta. We find the
solution of this system for even integer beta in the particular case of quantum
Painlev\'e II related to the soft edge of the spectrum for beta-ensembles. The
solution is given in terms of Calogero system of $\beta/2$ particles in an
additional time-dependent potential. Thus, we find another situation where
quantum integrability is reduced to classical integrability.


title:
A Novel Approach for Single Gene Selection Using Clustering and
  Dimensionality Reduction

abstract:
  We extend the standard rough set-based approach to deal with huge amounts of
numeric attributes versus small amount of available objects. Here, a novel
approach of clustering along with dimensionality reduction; Hybrid Fuzzy C
Means-Quick Reduct (FCMQR) algorithm is proposed for single gene selection.
Gene selection is a process to select genes which are more informative. It is
one of the important steps in knowledge discovery. The problem is that all
genes are not important in gene expression data. Some of the genes may be
redundant, and others may be irrelevant and noisy. In this study, the entire
dataset is divided in proper grouping of similar genes by applying Fuzzy C
Means (FCM) algorithm. A high class discriminated genes has been selected based
on their degree of dependence by applying Quick Reduct algorithm based on Rough
Set Theory to all the resultant clusters. Average Correlation Value (ACV) is
calculated for the high class discriminated genes. The clusters which have the
ACV value a s 1 is determined as significant clusters, whose classification
accuracy will be equal or high when comparing to the accuracy of the entire
dataset. The proposed algorithm is evaluated using WEKA classifiers and
compared. Finally, experimental results related to the leukemia cancer data
confirm that our approach is quite promising, though it surely requires further
research.


title:
Non-strongly-convex smooth stochastic approximation with convergence
  rate O(1/n)

abstract:
  We consider the stochastic approximation problem where a convex function has
to be minimized, given only the knowledge of unbiased estimates of its
gradients at certain points, a framework which includes machine learning
methods based on the minimization of the empirical risk. We focus on problems
without strong convexity, for which all previously known algorithms achieve a
convergence rate for function values of O(1/n^{1/2}). We consider and analyze
two algorithms that achieve a rate of O(1/n) for classical supervised learning
problems. For least-squares regression, we show that averaged stochastic
gradient descent with constant step-size achieves the desired rate. For
logistic regression, this is achieved by a simple novel stochastic gradient
algorithm that (a) constructs successive local quadratic approximations of the
loss functions, while (b) preserving the same running time complexity as
stochastic gradient descent. For these algorithms, we provide a non-asymptotic
analysis of the generalization error (in expectation, and also in high
probability for least-squares), and run extensive experiments on standard
machine learning benchmarks showing that they often outperform existing
approaches.


title:
Hide the interior region of core-shell nanoparticles with quantum
  invisible cloaks

abstract:
  By applying the interplay among the nodal points of partial waves, along with
the concept of streamline in fluid dynamics for the probability flux, a quantum
invisible cloak to the electron transport in a host semiconductor is
demonstrated by simultaneously guiding the probability flux outside the core
region and keeping the total scattering cross section negligible. As the
probability flux vanishes in the interior region, one can embed any material
inside a multiple core-shell sphere without affecting physical observables from
the outside. Our results reveal the possibility to design a protection shield
layer for fragile interior parts from the impact of transports of electrons.


title: Infrared spectroscopy of fullerene C60/anthracene adducts

abstract:
  Recent Spitzer Space Telescope observations of several astrophysical
environments such as Planetary Nebulae, Reflection Nebulae, and R Coronae
Borealis stars show the simultaneous presence of mid-infrared features
attributed to neutral fullerene molecules (i.e., C60) and polycyclic aromatic
hydrocarbons (PAHs). If C60 fullerenes and PAHs coexist in fullerene-rich space
environments, then C60 may easily form adducts with a number of different PAH
molecules; at least with catacondensed PAHs. Here we present the laboratory
infrared spectra (~2-25 um) of C60 fullerene and anthracene Dies-Alder mono-
and bis-adducts as produced by sonochemical synthesis. We find that
C60/anthracene Diels-Alder adducts display spectral features strikingly similar
to those from C60 (and C70) fullerenes and other unidentified infrared emission
features. Thus, fullerene-adducts - if formed under astrophysical conditions
and stable/abundant enough - may contribute to the infrared emission features
observed in fullerene-containing circumstellar/interstellar environments.

categories: astro-ph.SR astro-ph.IM physics.atm-clus physics.chem-ph physics.space-ph


title:
Ground state of the asymmetric Rabi model in the ultrastrong coupling
  regime

abstract:
  We study the ground states of the single- and two-qubit asymmetric Rabi
models, in which the qubit-oscillator coupling strengths for the
counterrotating-wave and corotating-wave interactions are unequal. We take the
transformation method to obtain the approximately analytical ground states for
both models and numerically verify its validity for a wide range of parameters
under the near-resonance condition. We find that the ground-state energy in
either the single- or two-qubit asymmetric Rabi model has an approximately
quadratic dependence on the coupling strengths stemming from different
contributions of the counterrotating-wave and corotating-wave interactions. For
both models, we show that the ground-state energy is mainly contributed by the
counterrotating-wave interaction. Interestingly, for the two-qubit asymmetric
Rabi model, we find that, with the increase of the coupling strength in the
counterrotating-wave or corotating-wave interaction, the two-qubit entanglement
first reaches its maximum then drops to zero. Furthermore, the maximum of the
two-qubit entanglement in the two-qubit asymmetric Rabi model can be much
larger than that in the two-qubit symmetric Rabi model.


title: Upper Rhine Valley: A migration crossroads of middle European oaks

abstract:
  The indigenous oak species (Quercus spp.) of the Upper Rhine Valley have
migrated to their current distribution range in the area after the transition
to the Holocene interglacial. Since post-glacial recolonization, they have been
subjected to ecological changes and human impact. By using chloroplast
microsatellite markers (cpSSRs), we provide detailed phylogeographic
information and we address the contribution of natural and human-related
factors to the current pattern of chloroplast DNA (cpDNA) variation. 626
individual trees from 86 oak stands including all three indigenous oak species
of the region were sampled. In order to verify the refugial origin, reference
samples from refugial areas and DNA samples from previous studies with known
cpDNA haplotypes (chlorotypes) were used. Chlorotypes belonging to three
different maternal lineages, corresponding to the three main glacial refugia,
were found in the area. These were spatially structured and highly introgressed
among species, reflecting past hybridization which involved all three
indigenous oak species. Site condition heterogeneity was found among groups of
populations which differed in terms of cpDNA variation. This suggests that
different biogeographic subregions within the Upper Rhine Valley were colonized
during separate post-glacial migration waves. Genetic variation was higher in
Quercus robur than in Quercus petraea, which is probably due to more efficient
seed dispersal and the more pronounced pioneer character of the former species.
Finally, stands of Q. robur established in the last 70 years were significantly
more diverse, which can be explained by the improved transportation ability of
seeds and seedlings for artificial regeneration of stands during this period.


title:
New views of crystal symmetry guided by profound admiration of the
  extraordinary works of Grassmann and Clifford

abstract:
  This paper shows how beginning with Justus Grassmann's work, Hermann
Grassmann was influenced in his mathematical thinking by crystallography. H.
Grassmann's Ausdehnungslehre in turn had a decisive influence on W.K. Clifford
in the genesis of geometric algebras. Geometric algebras have been expanded to
conformal geometric algebras, which provide an ideal framework for modern
computer graphics. Within this framework a new visualization of
three-dimensional crystallographic space groups has been created. The complex
beauty of this new visualization is shown by a range of images of a diamond
cell. Mathematical details are given in an appendix.


title:
Nonlinear Magneto-Optical and Magnetoelectric Phenomena in Topological
  Insulator Heterostructures

abstract:
  Three-dimensional topological insulator films in contact with magnetic layers
exhibit intriguing magneto-optical and magnetoelectric phenomena, but little is
known beyond the linear response regime. We demonstrate that the presence of
two electric fields parallel to the surface of the film induces a perpendicular
AC polarization, whereas a static polarization can be induced by applying a
single circularly polarized electromagnetic wave. These phenomena are
determined by the second-order susceptibility, which also controls the manner
in which the anomalous Hall current is modulated by a perpendicular AC electric
field. If the modulation frequency is low, the Hall effect is topologically
protected and the nonlinear response vanishes.


title: Bernoulli problem for rough domains

abstract:
  We consider the exterior free boundary Bernoulli problem in the case of a
rough given domain. An asymptotic analysis shows that the solution of the
initial problem can be approximated by the solution of a non-rough Bernoulli
problem at order 2. Numerical tests confirm these theoretical results.


title: Monotonicity formulas for obstacle problems with Lipschitz coefficients

abstract:
  We prove quasi-monotonicity formulas for classical obstacle-type problems
with energies being the sum of a quadratic form with Lipschitz coefficients,
and a H\"older continuous linear term. With the help of those formulas we are
able to carry out the full analysis of the regularity of free-boundary points
following the approaches by Caffarelli, Weiss and Monneau.


title: Root separation for reducible integer polynomials

abstract:
  We construct parametric families of (monic) reducible polynomials having two
roots very close to each other.


title: E8 lattice and the Kodaira dimension of orthogonal modular varieties

abstract:
  We prove that for any even lattice L of signature (2,n), the modular variety
defined by the orthogonal group of the lattice L+mE_8 is of general type when m
is sufficiently large.


title: Improved angular momentum evolution model for solar-like stars

abstract:
  We present new models for the rotational evolution of solar-like stars
between 1 Myr and 10 Gyr with the aim to reproduce the distributions of
rotational periods observed for star forming regions and young open clusters
within this age range. The models include a new wind braking law based on
recent numerical simulations of magnetized stellar winds and specific dynamo
and mass-loss prescriptions are adopted to tie angular momentum loss to angular
velocity. The model additionally assume constant angular velocity during the
disk accretion phase and allow for decoupling between the radiative core and
the convective envelope as soon as the former develops. We have developed
rotational evolution models for slow, median and fast rotators with initial
periods of 10, 7, and 1.4d, respectively. The models reproduce reasonably well
the rotational behaviour of solar-type stars between 1 Myr and 4.5 Gyr,
including PMS to ZAMS spin up, prompt ZAMS spin down, and the early-MS
convergence of surface rotation rates. We find the model parameters accounting
for the slow and median rotators are very similar to each other, with a disk
lifetime of 5 Myr and a core-envelope coupling timescale of 28-30 Myr. In
contrast, fast rotators have both shorter disk lifetime (2.5 Myr) and
core-envelope coupling timescale (12 Myr). We emphasize that these results are
highly dependent on the adopted braking law. We also report a tentative
correlation between initial rotational period and disk lifetime, which suggests
that protostellar spin-down by massive disks in the embedded phase is at the
origin of the initial dispersion of rotation rates in young stars. We conclude
that this class of semi-empirical models successfully grasp the main trends of
the rotational behaviour of solar-type stars as they evolve and make specific
predictions that may serve as a guide for further development.


title:
Detecting interspecific and geographic differentiation patterns in two
  interfertile oak species (Quercus petraea (Matt.) Liebl. and Q. robur L.)
  using small sets of microsatellite markers

abstract:
  Genetic analysis was carried out in order to provide insights into
differentiation among populations of two interfertile oak species, Quercus
petraea and Quercus robur. Gene flow between the two species, local adaptations
and speciation processes in general, may leave differential molecular
signatures across the genome. Three interspecific pairs of natural populations
from three ecologically different regions, one in central Europe (SW Germany)
and two in the Balkan Peninsula (Greece and Bulgaria) were sampled. Grouping of
highly informative SSR loci was made according to the component of variation
they express - interspecific or provenance specific. Species and provenance
discriminant loci were characterized based on FSTs. Locus specific FSTs were
tested for deviation from the neutral expectation both within and between
species. Data were then treated separately in a Bayesian analysis of genetic
structure. By using three species discriminant loci, high membership
probability to inferred species groups was achieved. On the other hand,
analysis of genetic structure based on five provenance discriminant loci was
correlated with geographic region and revealed shared genetic variation between
neighbouring Q. petraea and Q. robur. Small sets of highly variable nuclear
SSRs were sufficient to discriminate, either between species or between
provenances. Thus, an effective tool is provided for molecular identification
of both species and provenances. Furthermore, data suggest that a combination
of gene flow and natural selection forms these diversity patterns. Species
discriminant loci might represent genome regions affected by directional
selection, which maintains species identity. Provenance specific loci might
represent genome regions with high interspecific gene flow and common adaptive
patterns to local environmental factors.


title: All-optical reversible logic gate via adiabatic population transfer

abstract:
  The Toffoli gate is an essential logic element, which permits implementation
of a reversible processor. It is of relevance both for classical as well as
quantum logics. We propose and theoretically study all-optical implementations
of three-bit and four-bit Toffoli gates by application of adiabatic population
transfer techniques. For a three-bit Toffoli gate we use variants of stimulated
Raman adiabatic passage (STIRAP) processes in a $\Lambda$-type level scheme,
driven by two laser pulses at sufficiently large detunings. For the
implementation of a four-bit Toffoli gate, we apply reversible adiabatic
population transfer in five-level quantum systems, interacting with three laser
pulses. We demonstrate correct all-optical implementation of the truth table of
three-bit and four-bit Toffoli gates. Moreover, we derive conditions for
adiabatic evolution of the population dynamics and robust operation of the
gates.


title:
On the optimal weight function in the Goldston-Pintz-Yildirim method for
  finding small gaps between consecutive primes

abstract:
  We work out the optimization problem, initiated by K. Soundararajan, for the
choice of the underlying polynomial P used in the construction of the weight
function in the Goldston--Pintz--Yildirim method for finding small gaps between
primes. First we reformulate to a maximization problem on L^2[0,1] for a
self-adjoint operator T, the norm of which is then the maximal eigenvalue of T.
To find eigenfunctions and eigenvalues, we derive a differential equation which
can be explicitly solved. The aimed maximal value is S(k)=4/(k+ck^{1/3}),
achieved by the (k-1)st integral of x^{1-k/2}J_{k-2}(a_1\sqrt{x}), where a_1 is
the first positive root of the (k-2)nd Bessel function J_{k-2} and as such, is
asymptotically ck^{1/3} with a well-known constant c. As this naturally gives
rise to a number of technical problems in the application of the GPY method, we
also construct a polynomial P which is a simpler function yet it furnishes an
approximately optimal extremal quantity, 4/(k+Ck^{1/3}) with some other
constant C. In the forthcoming paper of J. Pintz (also to appear in the
Tur\'an-100 Memorial Volume by de Gruyter), it is indeed shown how this
quasi-optimal choice of the polynomial in the weight finally can exploit the
GPY method to its theoretical limits.


title:
Hot bottom burning and s-process nucleosynthesis in massive AGB stars at
  the beginning of the thermally-pulsing phase

abstract:
  We report the first spectroscopic identification of massive Galactic
asymptotic giant branch (AGB) stars at the beginning of the thermal pulse (TP)
phase. These stars are the most Li-rich massive AGBs found to date, super
Li-rich AGBs with logE(Li)~3-4. The high Li overabundances are accompanied by
weak or no s-process element (i.e. Rb and Zr) enhancements. A comparison of our
observations with the most recent hot bottom burning (HBB) and s-process
nucleosynthesis models confirms that HBB is strongly activated during the first
TPs but the 22Ne neutron source needs many more TP and third dredge-up episodes
to produce enough Rb at the stellar surface. We also show that the short-lived
element Tc, usually used as an indicator of AGB genuineness, is not detected in
massive AGBs which is in agreement with the theoretical predictions when the
22Ne neutron source dominates the s-process nucleosynthesis.


title:
Interpreting Eruptive Behavior in NOAA AR 11158 via the Region's
  Magnetic Energy and Relative Helicity Budgets

abstract:
  In previous works we introduced a nonlinear force-free method that
self-consistently calculates the instantaneous budgets of free magnetic energy
and relative magnetic helicity in solar active regions (ARs). Calculation is
expedient and practical, using only a single vector magnetogram per
computation. We apply this method to a timeseries of 600 high-cadence vector
magnetograms of the eruptive NOAA AR 11158 acquired by the Helioseismic and
Magnetic Imager onboard the Solar Dynamics Observatory over a five-day
observing interval. Besides testing our method extensively, we use it to
interpret the dynamical evolution in the AR, including eruptions. We find that
the AR builds large budgets of both free magnetic energy and relative magnetic
helicity, sufficient to power many more eruptions than the ones it gave within
the interval of interest. For each of these major eruptions, we find
eruption-related decreases and subsequent free-energy and helicity budgets that
are consistent with the observed eruption (flare and coronal-mass-ejection
[CME]) sizes. In addition, we find that (1) evolution in the AR is consistent
with the recently proposed (free) energy - (relative) helicity diagram of solar
ARs, (2) eruption-related decreases occur {\it before} the flare and the
projected CME-launch times, suggesting that CME progenitors precede flares, and
(3) self-terms of free energy and relative helicity most likely originate from
respective mutual-terms, following a progressive mutual-to-self conversion
pattern that most likely stems from magnetic reconnection. This results in the
non-ideal formation of increasingly helical pre-eruption structures and
instigates further research on the triggering of solar eruptions with magnetic
helicity firmly placed in the eruption cadre.


title:
Are the incompressible 3d Navier-Stokes equations locally ill-posed in
  the natural energy space?

abstract:
  An important open problem in the theory of the Navier-Stokes equations is the
uniqueness of the Leray-Hopf weak solutions with $L^2$ initial data.
  In this paper we give sufficient conditions for non-uniqueness in terms of
spectral properties of a natural linear operator associated to scale-invariant
solutions recently constructed in \cite{JiaSverak}. If the spectral conditions
are satisfied, non-uniqueness and ill-posedness can appear for quite benign
compactly supported data, just at the borderline of applicability of the
classical perturbation theory. The verification of the spectral conditions
seems to be approachable by relatively straightforward numerical simulations
which involve only smooth functions.


title: Minkowski valuations in a 2-dimensional complex vector space

abstract:
  The classification of continuous, translation invariant Minkowski valuations
which are contravariant (or covariant) with respect to the complex special
linear group is established in a 2-dimensional complex vector space. Every such
valuation is given by the sum of a valuation of degree of homogeneity 1 and 3.
In dimensions $m\geq 3$ such a classification was previously established and
only valuations of a degree of homogeneity 2m-1 appear.


title: Quasi-Local Conserved Charges in Covariant Theory of Gravity

abstract:
  In any generally covariant theory of gravity, we show the relationship
between the linearized asymptotically conserved current and its non-linear
completion through the identically conserved current. Our formulation for
conserved charges is based on the Lagrangian description, and so completely
covariant. By using this result, we give a prescription to define quasi-local
conserved charges in any higher derivative gravity. As applications of our
approach, we demonstrate the angular momentum invariance along the radial
direction of black holes and reproduce more efficiently the linearized
potential on the asymptotic AdS space.


title:
Charged fermion tunnelling from electrically and magnetically charged
  rotating black hole in de Sitter space

abstract:
  Thermal radiation of electrically charged fermions from rotating black hole
with electric and magnetic charges in de Sitter space is considered. The
tunnelling probabilities for outgoing and incoming particles are obtained and
the Hawking temperature is calculated. The relation for the classical action
for the particles in the black hole's background is also found.


title: Heat Kernel Empirical Laws on $\mathbb{U}_N$ and $\mathbb{GL}_N$

abstract:
  This paper studies the empirical measures of eigenvalues and singular values
for random matrices drawn from the heat kernel measures on the unitary groups
$\mathbb{U}_N$ and the general linear groups $\mathbb{GL}_N$, for
$N\in\mathbb{N}$. It establishes the strongest known convergence results for
the empirical eigenvalues in the $\mathbb{U}_N$ case, and the first known
almost sure convergence results for the eigenvalues and singular values in the
$\mathbb{GL}_N$ case. The limit noncommutative distribution associated to the
heat kernel measure on $\mathbb{GL}_N$ is identified as the projection of a
flow on an infinite-dimensional polynomial space. These results are then
strengthened from variance estimates to $L^p$ estimates for even integers $p$.


title: Bounded Variability of Metric Temporal Logic

abstract:
  Previous work has shown that reasoning with real-time temporal logics is
often simpler when restricted to models with bounded variability---where no
more than v events may occur every V time units, for given v, V. When reasoning
about formulas with intrinsic bounded variability, one can employ the simpler
techniques that rely on bounded variability, without any loss of generality.
What is then the complexity of algorithmically deciding which formulas have
intrinsic bounded variability?
  In this paper, we study the problem with reference to Metric Temporal Logic
(MTL). We prove that deciding bounded variability of MTL formulas is
undecidable over dense-time models, but with a undecidability degree lower than
generic dense-time MTL satisfiability. Over discrete-time models, instead,
deciding MTL bounded variability has the same exponential-space complexity as
satisfiability. To complement these negative results, we also briefly discuss
small fragments of MTL that are more amenable to reasoning about bounded
variability.


title: Energy gap at first-order quantum phase transitions: An anomalous case

abstract:
  We show that the rate of closing of the energy gap between the ground state
and the first excited state, as a function of system size, behaves in many
qualitatively different ways at first-order quantum phase transitions of the
infinite-range quantum XY model. Examples include polynomial, exponential and
even factorially fast closing of the energy gap, all of which coexist along a
single axis of the phase diagram representing the transverse field. This
variety emerges depending on whether or not the transverse field assumes a
rational number as well as on how the series of system size is chosen toward
the thermodynamic limit. We conclude that there is no generically applicable
rule to relate the rate of gap closing and the order of quantum phase
transitions as is often implied in many studies, in particular in relation to
the computational complexity of quantum annealing in its implementation as
quantum adiabatic computation.


title:
Invisible Higgs Decay in a Supersymmetric Inverse Seesaw Model with
  Light Sneutrino Dark Matter

abstract:
  Within the framework of a constrained Minimal Supersymmetric Standard Model
(cMSSM) augmented by an MSSM singlet-pair sector to account for the non-zero
neutrino masses by inverse seesaw mechanism, the lightest supersymmetric
particle (LSP) can be a mixed sneutrino with mass as small as 50 GeV,
satisfying all existing constraints, thus qualifying as a light dark matter
candidate. We study the possibility of the lightest neutral Higgs boson in this
model decaying invisibly into a pair of sneutrino LSPs, thereby giving rise to
novel missing energy signatures at the LHC. We perform a two-parameter global
analysis of the LHC Higgs data available till date to determine the optimal
invisible Higgs branching fraction in this scenario, and obtain a
$2\sigma(1\sigma)$ upper limit of 0.23 (0.12). A detailed cut-based analysis is
carried out thereafter, demonstrating the viability of our proposed signal
vis-a-vis backgrounds at the LHC.


title: Importance Nested Sampling and the MultiNest Algorithm

abstract:
  Bayesian inference involves two main computational challenges. First, in
estimating the parameters of some model for the data, the posterior
distribution may well be highly multi-modal: a regime in which the convergence
to stationarity of traditional Markov Chain Monte Carlo (MCMC) techniques
becomes incredibly slow. Second, in selecting between a set of competing models
the necessary estimation of the Bayesian evidence for each is, by definition, a
(possibly high-dimensional) integration over the entire parameter space; again
this can be a daunting computational task, although new Monte Carlo (MC)
integration algorithms offer solutions of ever increasing efficiency. Nested
sampling (NS) is one such contemporary MC strategy targeted at calculation of
the Bayesian evidence, but which also enables posterior inference as a
by-product, thereby allowing simultaneous parameter estimation and model
selection. The widely-used MultiNest algorithm presents a particularly
efficient implementation of the NS technique for multi-modal posteriors. In
this paper we discuss importance nested sampling (INS), an alternative
summation of the MultiNest draws, which can calculate the Bayesian evidence at
up to an order of magnitude higher accuracy than `vanilla' NS with no change in
the way MultiNest explores the parameter space. This is accomplished by
treating as a (pseudo-)importance sample the totality of points collected by
MultiNest, including those previously discarded under the constrained
likelihood sampling of the NS algorithm. We apply this technique to several
challenging test problems and compare the accuracy of Bayesian evidences
obtained with INS against those from vanilla NS.


title: Zeno dynamics in quantum open systems

abstract:
  Quantum Zeno effect shows that frequent observations can slow down or even
stop the unitary time evolution of an unstable quantum system. This effect can
also be regarded as a physical consequence of the the statistical
indistinguishability of neighboring quantum states. The accessibility of
quantum Zeno dynamics under unitary time evolution can be quantitatively
estimated by quantum Zeno time in terms of Fisher information. In this work, we
investigate the accessibility of quantum Zeno dynamics in quantum open systems
by calculating noisy Fisher information, in which a trace preserving and
completely positive map is assumed. We firstly study the consequences of
non-Markovian noise on quantum Zeno effect and give the exact forms of the
dissipative Fisher information and the quantum Zeno time. Then, for the
operator-sum representation, an achievable upper bound of the quantum Zeno time
is given with the help of the results in noisy quantum metrology. It is of
significance that the noise affecting the accuracy in the entanglement-enhanced
parameter estimation can conversely be favorable for the accessibility of
quantum Zeno dynamics of entangled states.


title:
LOTS as Fixed Point Sets: An Application of Tarski's Fixed Point Theorem
  (draft)

abstract:
  This article has been withdrawn in 2013.
  The class of LOTS (linearly ordered topological spaces) contains many
important spaces, like the set of real numbers, the set of rational numbers and
the ordinals. Such spaces have rich topological properties, which are not
necessarily hereditary.


title:
Effective field theory for two-species bosons in an optical lattice:
  Multiple order, the Nambu-Goldstone bosons, the Higgs mode and vortex lattice

abstract:
  In the previous papers, we studied the bosonic t-J mode and derived an
effective field theory, which is a kind of quantum XY model. The bosonic t-J
model is expected to be realized by experiments of two-component cold atoms in
an optical lattice. In this paper, we consider a similar XY model that
describes phase diagram of the t-J model with a mass difference. Phase diagram
and critical behavior of the quantum XY model are clarified by means of the
Monte-Carlo simulations. Effective field theory that describes the phase
structure and low-energy excitations of the quantum XY model is derived.
Nambu-Goldstone bosons and the Higgs mode are studied by using the effective
field theory and interesting findings are obtained for the system with multiple
order, i.e., Bose-Einstein condensations and pseudo-spin symmetry. We also
investigate physical properties of the quantum XY model in an effective
magnetic field that is realized by rotating the optical lattice, etc. We show
that low-energy states of the system strongly depend on the strength of the
"magnetic field". For some specific strength of the magnetic field, vortex
lattice forms and the correlation function of the bosons exhibits solid like
behavior, which is a kind of Bose-Einstein condensation.


title:
KIC 11285625: a double-lined spectroscopic binary with a gamma Dor
  pulsator discovered from Kepler space photometry

abstract:
  We present the first binary modelling results for the pulsating eclipsing
binary KIC 11285625, discovered by the Kepler mission. An automated method to
disentangle the pulsation spectrum and the orbital variability in high quality
light curves, was developed and applied. The goal was to obtain accurate
orbital and component properties, in combination with essential information
derived from spectroscopy. A binary model for KIC 11285625 was obtained, using
a combined analysis of high-quality space-based Kepler light curves and
ground-based high-resolution HERMES echelle spectra. The binary model was used
to separate the pulsation characteristics from the orbital variability in the
Kepler light curve in an iterative way. We used an automated procedure to
perform this task, based on the JKTEBOP binary modelling code, and adapted
codes for frequency analysis and prewhitening of periodic signals. Using a
disentangling technique applied to the composite HERMES spectra, we obtained a
higher signal-to-noise mean component spectrum for both the primary and the
secondary. A model grid search method for fitting synthetic spectra was used
for fundamental parameter determination for both components. Accurate orbital
and component properties of KIC 11285625 were derived, and we have obtained the
pulsation spectrum of the gamma Dor pulsator in the system. Detailed analysis
of the pulsation spectrum revealed amplitude modulation on a time scale of a
hundred days, and strong indications of frequency splittings at both the
orbital frequency, and the rotational frequency derived from spectroscopy.


title: Diffraction at the LHC

abstract:
  We show that the diffractive pp (and p\bar{p}) data (on \sigma_tot,
d\sigma_el/dt, proton dissociation into low-mass systems, \sigma^D(low M), and
high-mass dissociation, d\sigma/d(\Delta\eta)) in a wide energy range from
CERN-ISR to LHC energies, may be described in a two-channel eikonal model with
only one `effective' pomeron. By allowing the pomeron coupling to the
diffractive eigenstates to depend on the collider energy (as is expected
theoretically) we are able to explain the low value of \sigma^D(low M) measured
at the LHC. We calculate the survival probability, S^2, of a rapidity gap to
survive `soft rescattering'. We emphasize that the values found for S^2 are
particularly sensitive to the detailed structure of the diffractive
eigenstates.


title:
Fast low-rank solution of the Poisson equation with application to the
  Stokes problem

abstract:
  We consider the problem of computing approximate solution of Poisson equation
in the low-parametric tensor formats. We propose a new algorithm to compute the
solution based on the cross approximation algorithm in the frequency space, and
it has better complexity with respect to ranks in comparison with standard
algorithms, which are based on the exponential sums approximation. To
illustrate the effectiveness of our solver, we incorporate into a Uzawa solver
for the Stokes problem on semi-staggered grid as a subsolver. The resulting
solver outperforms the standard method for $n \geq 256$.


title:
A Comparison of Solar Cycle Variations in the Equatorial Rotation Rates
  of the Sun's Subsurface, Surface, Corona, and Sunspot Groups

abstract:
  Using the Solar Optical Observing Network (SOON) sunspot-group data for the
period 1985-2010, the variations in the annual mean equatorial-rotation rates
of the sunspot groups are determined and compared with the known variations in
the solar equatorial-rotation rates determined from the following data: i) the
plasma rotation rates at 0.94Rsun, 0.95Rsun,...,1.0Rsun measured by Global
Oscillation Network Group (GONG) during the period 1995-2010, ii) the data on
the soft X-ray corona determined from Yohkoh/SXT full disk images for the years
1992-2001, iii) the data on small bright coronal structures (SBCS) which were
traced in Solar and Heliospheric Observatory (SOHO)/EIT images during the
period 1998-2006, and iv) the Mount Wilson Doppler-velocity measurements during
the period 1986-2007. A large portion (up to approximate 30 deg latitude) of
the mean differential-rotation profile of the sunspot groups lies between those
of the internal differential-rotation rates at 0.94Rsun and 0.98Rsun.The
variation in the yearly mean equatorial-rotation rate of the sunspot groups
seems to be lagging that of the equatorial-rotation rate determined from the
GONG measurements by one to two years.The amplitude of the latter is very
small.The solar-cycle variation in the equatorial-rotation rate of the solar
corona closely matches that determined from the sunspot-group data.The
variation in the equatorial-rotation rate determined from the Mount Wilson
Doppler-velocity data closely resembles the corresponding variation in the
equatorial-rotation rate determined from the sunspot-group data that included
the values of the abnormal angular motions (> 3 deg per day) of the sunspot
groups. Implications of these results are pointed out.


title: Luminosities of radio Pulsars

abstract:
  Luminosity is an intrinsic property of radio pulsars related to the
properties of the magnetospheric plasma and the beam geometry, and inversely
proportional to the observing frequency. In traditional models, luminosity has
been considered as a function of the spin parameters of pulsars. On the other
hand, parameter independent models like power law and lognormal have been also
used to fit the observed luminosities. Some of the older studies on pulsar
luminosities neglected observational biases, but all of the recent studies
tried to model observational effects as accurately as possible. Luminosities of
pulsars in globular clusters and in the Galactic disk have been studied
separately. Older studies concluded that these two categories of pulsars have
different luminosity distributions, but the most recent study concluded that
those are the same. This article reviews all significant works on pulsar
luminosities and discusses open questions.


title: Novel coupling scheme to control dynamics of coupled discrete systems

abstract:
  We present a new coupling scheme to control spatio-temporal patterns and
chimeras on 1-d and 2-d lattices and random networks of discrete dynamical
systems. The scheme involves coupling with an external lattice or network of
damped systems. When the system network and external network are set in a
feedback loop, the system network can be controlled to a homogeneous steady
state or synchronized periodic state with suppression of the chaotic dynamics
of the individual units. The control scheme has the advantage that its design
does not require any prior information about the system dynamics or its
parameters and works effectively for a range of parameters of the control
network. We analyze the stability of the controlled steady state or amplitude
death state of lattices using the theory of circulant matrices and
Routh-Hurwitz's criterion for discrete systems and this helps to isolate
regions of effective control in the relevant parameter planes. The conditions
thus obtained are found to agree well with those obtained from direct numerical
simulations in the specific context of lattices with logistic map and Henon map
as on-site system dynamics. We show how chimera states developed in an
experimentally realizable 2-d lattice can be controlled using this scheme. We
propose this mechanism can provide a phenomenological model for the control of
spatio-temporal patterns in coupled neurons due to non-synaptic coupling with
the extra cellular medium. We extend the control scheme to regulate dynamics on
random networks and adapt the master stability function method to analyze the
stability of the controlled state for various topologies and coupling
strengths.


title: Lattice charge models and core level shifts in disordered alloys

abstract:
  Differences in core level binding energies between atoms belonging to the
same chemical species can be related to differences in their intra- and
extra-atomic charge distributions, and differences in how their core holes are
screened. With this in mind, we consider the charge-excess functional model
(CEFM) for net atomic charges in alloys [E. Bruno et al., Phys. Rev. Lett. 91,
166401 (2003)]. We begin by deriving the CEFM energy function in order to
elucidate the approximations which underpin this model. We thereafter consider
the particular case of the CEFM in which the strength of the `local
interactions' within all atoms are the same. We show that for binary alloys the
ground state charges of this model can be expressed in terms of charge transfer
between all pairs of unlike atoms analogously to the linear charge model [R.
Magri et al., Phys. Rev. B 42, 11388 (1990)]. Hence the model considered is a
generalization of the linear charge model for alloys containing more than two
chemical species. We then determine the model's unknown `geometric factors'
over a wide range of parameter space. These quantities are linked to the nature
of charge screening in the model, and we illustrate that the screening becomes
increasingly universal as the strength of the local interactions is increased.
We then use the model to derive analytical expressions for various physical
quantities, including the Madelung energy and the disorder broadening in the
core level binding energies. These expressions are applied to ternary random
alloys, for which it is shown that the Madelung energy and magnitude of
disorder broadening are maximized at the composition at which the two species
with the largest `electronegativity difference' are equal, while the remaining
species having a vanishing concentration. This result is somewhat
counterintuitive with regards to the disorder broadening since it does not...


title:
Direct proof of unique magnetic and superconducting phases in
  superoxygenated high-Tc cuprates

abstract:
  We present a combined magnetic neutron scattering and muon spin rotation
study of the nature of the magnetic and superconducting phases in
electronically phase separated La(2-x)Sr(x)CuO(4+y), x = 0.04, 065, 0.09. For
all samples, we find long-range modulated magnetic order below T_N ~ T_c = 39
K. In sharp contrast wit oxygen-stoichiometric La(2-x)Sr(x)CuO(4), we find that
the magnetic propagation vector as well as the ordered magnetic moment is
independent of Sr content and consistent with that of the 'striped' cuprates.
Our study provides direct proof that superoxygenation in La(2-x)Sr(x)CuO(4+y)
allows the spin stripe ordered phase to emerge and phase separate from
superconducting regions with the hallmarks of optimally doped
oxygen-stoichiometric La(2-x)Sr(x)CuO(4).


title:
Unifying the observational diversity of isolated neutron stars via
  magneto-thermal evolution models

abstract:
  Observations of magnetars and some of the high magnetic field pulsars have
shown that their thermal luminosity is systematically higher than that of
classical radio-pulsars, thus confirming the idea that magnetic fields are
involved in their X-ray emission. Here we present the results of 2D simulations
of the fully-coupled evolution of temperature and magnetic field in neutron
stars, including the state-of-the-art kinetic coefficients and, for the first
time, the important effect of the Hall term. After gathering and thoroughly
re-analysing in a consistent way all the best available data on isolated,
thermally emitting neutron stars, we compare our theoretical models to a data
sample of 40 sources. We find that our evolutionary models can explain the
phenomenological diversity of magnetars, high-B radio-pulsars, and isolated
nearby neutron stars by only varying their initial magnetic field, mass and
envelope composition. Nearly all sources appear to follow the expectations of
the standard theoretical models. Finally, we discuss the expected outburst
rates and the evolutionary links between different classes. Our results
constitute a major step towards the grand unification of the isolated neutron
star zoo.


title:
The Orthogonal 2D Planes Split of Quaternions and Steerable Quaternion
  Fourier Transformations

abstract:
  The two-sided quaternionic Fourier transformation (QFT) was introduced in
\cite{Ell:1993} for the analysis of 2D linear time-invariant
partial-differential systems. In further theoretical investigations
\cite{10.1007/s00006-007-0037-8, EH:DirUP_QFT} a special split of quaternions
was introduced, then called $\pm$split. In the current \change{chapter} we
analyze this split further, interpret it geometrically as \change{an}
\emph{orthogonal 2D planes split} (OPS), and generalize it to a freely
steerable split of $\H$ into two orthogonal 2D analysis planes. The new general
form of the OPS split allows us to find new geometric interpretations for the
action of the QFT on the signal. The second major result of this work is a
variety of \emph{new steerable forms} of the QFT, their geometric
interpretation, and for each form\change{,} OPS split theorems, which allow
fast and efficient numerical implementation with standard FFT software.


title: "Not not bad" is not "bad": A distributional account of negation

abstract:
  With the increasing empirical success of distributional models of
compositional semantics, it is timely to consider the types of textual logic
that such models are capable of capturing. In this paper, we address
shortcomings in the ability of current models to capture logical operations
such as negation. As a solution we propose a tripartite formulation for a
continuous vector space representation of semantics and subsequently use this
representation to develop a formal compositional notion of negation within such
models.


title:
Image segmentation by optimal and hierarchical piecewise constant
  approximations

abstract:
  Piecewise constant image approximations of sequential number of segments or
clusters of disconnected pixels are treated. The method of majorizing of
optimal approximation sequence by hierarchical sequence of image approximations
is proposed. A generalization for multidimensional case of color and
multispectral images is foreseen.


title:
ATLAAS-P2P: a two layer network solution for easing the resource
  discovery process in unstructured networks

abstract:
  ATLAAS-P2P is a two-layered P2P architecture for developing systems providing
resource aggregation and approximated discovery in P2P networks. Such systems
allow users to search the desired resources by specifying their requirements in
a flexible and easy way. From the point of view of resource providers, this
system makes available an effective solution supporting providers in being
reached by resource requests.


title: Transient and self-limited nanostructures on patterned surfaces

abstract:
  Site-controlled quantum dots formed during the deposition of (Al)GaAs layers
by metalorganic vapor-phase epitaxy on GaAs(111)B substrates patterned with
inverted pyramids result in geometric and compositional self-ordering along the
vertical axis of the template. We describe a theoretical scheme that reproduces
the experimentally-observed time-dependent behavior of this process, including
the evolution of the recess and the increase of Ga incorporation along the base
of the template to stationary values determined by alloy composition and other
growth parameters. Our work clarifies the interplay between kinetics and
geometry for the development of self-ordered nanostructures on patterned
surfaces, which is essential for the reliable on-demand design of confined
systems for applications to quantum optics.


title:
Quantum simulation of a lattice Schwinger model in a chain of trapped
  ions

abstract:
  We discuss how a lattice Schwinger model can be realized in a linear ion
trap, allowing a detailed study of the physics of Abelian lattice gauge
theories related to one-dimensional quantum electrodynamics. Relying on the
rich quantum-simulation toolbox available in state-of-the-art trapped-ion
experiments, we show how one can engineer an effectively gauge-invariant
dynamics by imposing energetic constraints, provided by strong Ising-like
interactions. Applying exact diagonalization to ground-state and time-dependent
properties, we study the underlying microscopic model, and discuss undesired
interaction terms and other imperfections. As our analysis shows, the proposed
scheme allows for the observation in realistic setups of spontaneous parity-
and charge-symmetry breaking, as well as false-vacuum decay. Besides an
implementation aimed at larger ion chains, we also discuss a minimal setting,
consisting of only four ions in a simpler experimental setup, which enables to
probe basic physical phenomena related to the full many-body problem. The
proposal opens a new route for analog quantum simulation of high-energy and
condensed-matter models where gauge symmetries play a prominent role.

categories: cond-mat.quant-gas cond-mat.str-el hep-lat quant-ph


title:
Algebraic reformulation of Connes embedding problem and the free group
  algebra

abstract:
  We give a modification of I. Klep and M. Schweighofer algebraic reformulation
of Connes' embedding problem by considering *-algebra of the countably
generated free group. This allows to consider only quadratic polynomials in
unitary generators instead of arbitrary polynomials in self-adjoint generators.


title:
A Practical Introduction to Tensor Networks: Matrix Product States and
  Projected Entangled Pair States

abstract:
  This is a partly non-technical introduction to selected topics on tensor
network methods, based on several lectures and introductory seminars given on
the subject. It should be a good place for newcomers to get familiarized with
some of the key ideas in the field, specially regarding the numerics. After a
very general introduction we motivate the concept of tensor network and provide
several examples. We then move on to explain some basics about Matrix Product
States (MPS) and Projected Entangled Pair States (PEPS). Selected details on
some of the associated numerical methods for 1d and 2d quantum lattice systems
are also discussed.


title: On the genus of meromorphic functions

abstract:
  We define the class of Left Located Divisor (LLD) meromorphic functions and
their vertical order $m_0(f)$ and their convergence exponent $d(f)$. When
$m_0(f)\leq d(f)$ we prove that their Weierstrass genus is minimal. This
explains the phenomena that many classical functions have minimal Weierstrass
genus, for example Dirichlet series, the $\Gamma$-function, and trigonometric
functions.


title: The Dirac operator of a graph

abstract:
  We discuss some linear algebra related to the Dirac matrix D of a finite
simple graph G=(V,E).


title: Efficient Exploration of the Space of Reconciled Gene Trees

abstract:
  Gene trees record the combination of gene level events, such as duplication,
transfer and loss, and species level events, such as speciation and extinction.
Gene tree-species tree reconciliation methods model these processes by drawing
gene trees into the species tree using a series of gene and species level
events. The reconstruction of gene trees based on sequence alone almost always
involves choosing between statistically equivalent or weakly distinguishable
relationships that could be much better resolved based on a putative species
tree. To exploit this potential for accurate reconstruction of gene trees the
space of reconciled gene trees must be explored according to a joint model of
sequence evolution and gene tree-species tree reconciliation.
  Here we present amalgamated likelihood estimation (ALE), a probabilistic
approach to exhaustively explore all reconciled gene trees that can be
amalgamated as a combination of clades observed in a sample of trees. We
implement ALE in the context of a reconciliation model, which allows for the
duplication, transfer and loss of genes. We use ALE to efficiently approximate
the sum of the joint likelihood over amalgamations and to find the reconciled
gene tree that maximizes the joint likelihood.
  We demonstrate using simulations that gene trees reconstructed using the
joint likelihood are substantially more accurate than those reconstructed using
sequence alone. Using realistic topologies, branch lengths and alignment sizes,
we demonstrate that ALE produces more accurate gene trees even if the model of
sequence evolution is greatly simplified. Finally, examining 1099 gene families
from 36 cyanobacterial genomes we find that joint likelihood-based inference
results in a striking reduction in apparent phylogenetic discord, with 24%, 59%
and 46% percent reductions in the mean numbers of duplications, transfers and
losses.


title:
Bianchi type V bulk viscous cosmological models with particle creation
  in General Relativity

abstract:
  In this paper, a spatially homogeneous and anisotropic Bianchi type V model
filled with an imperfect fluid with bulk viscosity and particle creation, is
investigated within the framework of General Relativity. Particle creation and
bulk viscosity have been considered as separate irreversible processes. The
energy- momentum tensor is modified to accommodate the viscous pressure and
creation pressure which is associated with creation of matter out of
gravitational field. Exact solutions of the field equations are obtained by
applying a special law of variation of Hubble parameter. Using this assumption,
we obtain two types of cosmological models. We find a singularity in the first
model whereas second model is non-singular. Further we separately study the
bulk viscosity and particle creation in each model considering four different
cases. The bulk viscosity coefficient $\zeta$ is obtained for Truncated, Full
Causal and Eckart theories in all cases. All physical parameters are calculated
and thoroughly discussed in both models.


title: Superconformal symmetry and higher-derivative Lagrangians

abstract:
  Superconformal methods are useful to build invariant actions in supergravity.
We have a good insight in the possibilities of actions that are at most
quadratic in spacetime derivatives, but insight in general higher-derivative
actions is missing. Recently higher-derivative actions got more attention for
several applications. One of these is the understanding of finiteness of loop
computations in supergravities. Divergences can only occur if invariant
counterterms or anomalies exist. One can wonder whether conformal symmetry
might also play a role in this context. In order to construct higher-derivative
supergravities with the conformal methods, one should first get more insight in
such rigid supersymmetric actions with extra fermionic symmetries. We show how
Dirac--Born--Infeld actions with Volkov--Akulov supersymmetries can be
constructed in all orders.


title: Probing Terahertz Metamaterials with Subwavelength Optical Fibers

abstract:
  Transmission through a subwavelength terahertz fiber, which is positioned in
parallel to a frequency selective surface, is studied using several finite
element tools. Both the band diagram technique and the port-based scattering
matrix technique are used to explain the nature of various resonances in the
fiber transmission spectrum. First, we observe that spectral positions of most
of the transmission peaks in the port-based simulation can be related to the
positions of Van Hove singularities in the band diagram of a corresponding
infinite periodic system. Moreover, spectral shape of most of the features in
the fiber transmission spectrum can be explained by superposition of several
Fano-type resonances. We also show that center frequencies and bandwidths of
these resonances and, as a consequence, spectral shape of the resulting
transmission features can be tuned by varying the fiber-metamaterial
separation.


title: Paradigms for Parameterized Enumeration

abstract:
  The aim of the paper is to examine the computational complexity and
algorithmics of enumeration, the task to output all solutions of a given
problem, from the point of view of parameterized complexity. First we define
formally different notions of efficient enumeration in the context of
parameterized complexity. Second we show how different algorithmic paradigms
can be used in order to get parameter-efficient enumeration algorithms in a
number of examples. These paradigms use well-known principles from the design
of parameterized decision as well as enumeration techniques, like for instance
kernelization and self-reducibility. The concept of kernelization, in
particular, leads to a characterization of fixed-parameter tractable
enumeration problems.


title: Chromatic effects in the 21 cm global signal from the cosmic dawn

abstract:
  The redshifted 21 cm brightness distribution from neutral hydrogen is a
promising probe into the cosmic dark ages, cosmic dawn, and re-ionization.
LOFAR's Low Band Antennas (LBA) may be used in the frequency range 45 MHz to 85
MHz (30>z>16) to measure the sky averaged redshifted 21 cm brightness
temperature as a function of frequency, or equivalently, cosmic redshift. These
low frequencies are affected by strong Galactic foreground emission that is
observed through frequency dependent ionospheric and antenna beam distortions
which lead to chromatic mixing of spatial structure into spectral structure.
Using simple models, we show that (i) the additional antenna temperature due to
ionospheric refraction and absorption are at a \sim 1% level--- 2 to 3 orders
of magnitude higher than the expected 21 cm signal, and have an approximate
\nu^{-2} dependence, (ii) ionospheric refraction leads to a knee-like
modulation on the sky spectrum at \nu\approx 4\times plasma frequency. Using
more realistic simulations, we show that in the measured sky spectrum, more
than 50% of the 21 cm signal variance can be lost to confusion from foregrounds
and chromatic effects. We conclude that foregrounds and chromatic mixing may
not be subtracted as generic functions of frequency as previously thought, but
must rather be carefully modeled using additional priors and interferometric
measurements.


title:
On the feasibility to study inverse proximity effect in a single S/F
  bilayer by Polarized Neutron Reflectometry

abstract:
  Here we report on a feasibility study aiming to explore the potential of
Polarized Neutron Reflectometry (PNR) for detecting the inverse proximity
effect in a single superconducting/ferromagnetic bilayer. Experiments,
conducted on the V(40nm)/Fe(1nm) S/F bilayer, have shown that experimental spin
asymmetry measured at T = 0.5TC is shifted towards higher Q values compared to
the curve measured at T = 1.5TC. Such a shift can be described by the
appearance in superconducting vanadium of magnetic sub-layer with thickness of
7 nm and magnetization of +0.8 kG.


title:
Gauge invariant method for maximum simplification of the field strength
  in non-Abelian Yang-Mills theories

abstract:
  A new local gauge invariant method is introduced in order to maximally
simplify the expression for a SU(2) non-Abelian field strength. The new tetrads
introduced in previous works are going to play a fundamental role in the
algorithm presented in this manuscript. Three new local gauge invariant objects
are going to guide us through the process of making a field strength block
diagonal. The process is also covariant. Any non-trivial isospace field
strength projection will become block diagonal through this algorithm. Along
with the local gauge invariant method already developed in order to diagonalize
the stress-energy tensor, we have with this new local gauge invariant method to
maximally simplify the field strength, a new gauge invariant method to classify
Yang-Mills field theories.


title:
Ferromagnetism in neutron and charge neutral beta-equilibrated nuclear
  matter

abstract:
  Ferromagnetism in infinite neutron matter as well as beta equilibrated,
charge neutral, dense, and infinite nuclear matter is investigated using a
model of interacting baryons and mesons. The standard minimal couplings between
the magnetic field and the particle charges as well as the baryon dipole
moments are included in the Lagrangian density. Minimizing the energy density
with respect to the magnetic field yields a self-consistent expression for the
ferromagnetic field. We calculate the phase boundary at a given density by
increasing the strength of the baryon dipole moments till the energy density of
magnetized matter is lower than that of unmagnetized matter. We find that,
depending on the density, it is crossed when the baryon dipole moments are
increased by a factor of 35. It is also sensitive to the details of the nuclear
matter parameterizations and crossing it induces a magnetic field of $\sim
10^{17}$ gauss.


title:
A fast and reliable method to measure stellar differential rotation from
  photometric data

abstract:
  Co-rotating spots at different latitudes on the stellar surface generate
periodic photometric variability and can be useful proxies to detect
Differential Rotation (DR). DR is a major ingredient of the solar dynamo but
observations of stellar DR are rather sparse. In view of the Kepler space
telescope we are interested in the detection of DR using photometric
information of the star, and to develop a fast method to determine stellar DR
from photometric data. We ran a large Monte-Carlo simulation of differentially
rotating spotted stars with very different properties to investigate the
detectability of DR. For different noise levels the resulting light curves are
prewhitened using Lomb-Scargle periodograms to derive parameters for a global
sine fit to detect periodicities. We show under what conditions DR can
successfully be detected from photometric data, and in which cases the light
curve provides insufficient or even misleading information on the stellar
rotation law. In our simulations, the most significant period P1_{out} could be
detected in 96.2% of all light curves. Detection of a second period close to
P1_{out} is the signature of DR in our model. For the noise-free case, in 64.2%
of all stars such a period was found. Calculating the measured latitudinal
shear of two distinct spots \alpha_{out}, and comparing it to the known
original spot rotation rates shows that the real value is on average 3.2%
lower. Comparing the total equator-to-pole shear $\alpha$ to $\alpha_{out}$ we
find that $\alpha$ is underestimated by 8.8%, esp. the detection of DR for
stars with $\alpha$ < 6% is challenging. Finally, we apply our method to four
differentially rotating Kepler stars and find close agreement with results from
detailed modeling. Our method is capable of measuring stellar rotation periods
and detecting DR with relatively high accuracy and is suitable for large data
sets.


title:
Production of strangeness -1 and -2 hypernuclei within a field theoretic
  model

abstract:
  We present an overview of a fully covariant formulation for describing the
production of strangeness -1 and -2 hypernuclei using probes of different
kinds. This theory is based on an effective Lagrangian picture and it focuses
on production amplitudes that are described via creation, propagation and decay
into relevant channel of intermediate baryonic resonance states in the initial
collision of the projectile with one of the target nucleons. The bound state
nucleon and hyperon wave functions are obtained by solving the Dirac equation
with appropriate scalar and vector potentials. Specific examples are discussed
for reactions which are of interest to current and future experiments on the
hypernuclear production.


title: Dynamics of Non-supersymmetric Flavours

abstract:
  We investigate the effect of the back-reaction by non-supersymmetric probes
in the Kuperstein-Sonnenschein model. In the limit where the back-reaction is
small, we discuss physical properties of the back-reacted geometry. We further
introduce additional probe flavours in this back-reacted geometry and study in
detail the phase structure of this sector when a constant electromagnetic field
or a chemical potential are present. We find that the Landau pole, which serves
as the UV cut-off of the background geometry, also serves as an important scale
in the corresponding thermodynamics of the additional flavour sector. We note
that since these additional probe flavours are indistinguishable from the
back-reacting flavours, the results we obtain point to a much richer phase
structure of the system.


title: Probing the topological properties of the Jackiw-Rebbi model with light

abstract:
  The Jackiw-Rebbi model describes a one-dimensional Dirac particle coupled to
a soliton field and can be equivalently thought of as the model describing a
Dirac particle under a Lorentz scalar potential. Neglecting the dynamics of the
soliton field, a kink in the background soliton profile yields a topologically
protected zero-energy mode for the particle, which in turn leads to charge
fractionalization. We show here that the model can be realized in a driven
slow-light setup, where photons mimic the Dirac particles and the soliton field
can be implemented-and tuned-by adjusting optical parameters such as the
atom-photon detuning. Furthermore, we discuss how the existence of the
zero-mode, and its topological stability, can be probed naturally by analyzing
the transmission spectrum. We conclude by doing an analysis of the robustness
of our approach against possible experimental errors in engineering the
Jackiw-Rebbi Hamiltonian in this optical set up.


title: No unique quadratic ephemeris for VW Cep

abstract:
  From the eclipsing binary VW Cep, 1963 epochs of primary and secondary minima
have been registered since 1926. Because VW Cep is a shallow contact binary the
direction of the flow from one component to the other could possibly be
reversed. We aim to fit the observed eclipses into a scenario in which
reversals may occur. Orbital period changes can not be fitted into a unique
quadratic ephemeris, because of discontinuities in the (O-C) vs E graph. We try
to obtain better agreement through the allowance of RLOF reversal in this
binary system. From 1926 until 1943 the orbital period increase fits into a
model of mass transfer from the less massive component. From 1946 on the
direction of the mass transfer changed so that the most massive component
became the donor star, as shown by a systematic period decrease. A sudden
period increase in 1999 introduces a currently underway episode of mass
transfer from the less massive component. The ephemeris of VW Cep can be fitted
into a model in which the direction of the mass transfer was reversed twice
since 1926.


title: Vanishing sequences and Okounkov bodies

abstract:
  We define and study the vanishing sequence along a real valuation of sections
of a line bundle on a projective variety. Building on previous work of the
first author with Huayi Chen, we prove an equidistribution result for vanishing
sequences of large powers of a big line bundle, and study the limit measure. In
particular, the latter is described in terms of restricted volumes for
divisorial valuations. We also show on an example that the associated concave
function on the Okounkov body can be discontinuous at boundary points.


title: Extending Partial Representations of Interval Graphs

abstract:
  Interval graphs are intersection graphs of closed intervals of the real-line.
The well-known computational problem, called recognition, asks whether an input
graph $G$ can be represented by closed intervals, i.e., whether $G$ is an
interval graph. There are several linear-time algorithms known for recognizing
interval graphs, the oldest one is by Booth and Lueker [J. Comput. System Sci.,
13 (1976)] based on PQ-trees.
  In this paper, we study a generalization of recognition, called partial
representation extension. The input of this problem consists of a graph $G$
with a partial representation $\cal R'$ fixing the positions of some intervals.
The problem asks whether it is possible to place the remaining interval and
create an interval representation $\cal R$ of the entire graph $G$ extending
$\cal R'$. We generalize the characterization of interval graphs by Fulkerson
and Gross [Pac. J. Math., 15 (1965)] to extendible partial representations.
Using it, we give a linear-time algorithm for partial representation extension
based on a reordering problem of PQ-trees.


title:
Single-photon blockade in doubly resonant nanocavities with second-order
  nonlinearity

abstract:
  We propose the use of nanostructured photonic nanocavities made of
second-order nonlinear materials as prospective passive devices to generate
strongly sub-Poissonian light via single-photon blockade of an input coherent
field. The simplest scheme is based on the requirement that the nanocavity be
doubly resonant, i.e. possess cavity modes with good spatial overlap at both
the fundamental and second-harmonic frequencies. We discuss feasibility of this
scheme with state-of-the art nanofabrication technology, and the possibility to
use it as a passive single-photon source on-demand.


title: A General Geometric Fourier Transform

abstract:
  The increasing demand for Fourier transforms on geometric algebras has
resulted in a large variety. Here we introduce one single straight forward
definition of a general geometric Fourier transform covering most versions in
the literature. We show which constraints are additionally necessary to obtain
certain features like linearity or a shift theorem. As a result, we provide
guidelines for the target-oriented design of yet unconsidered transforms that
fulfill requirements in a specific application context. Furthermore, the
standard theorems do not need to be shown in a slightly different form every
time a new geometric Fourier transform is developed since they are proved here
once and for all.


title: A General Geometric Fourier Transform Convolution Theorem

abstract:
  The large variety of Fourier transforms in geometric algebras inspired the
straight forward definition of ``A General Geometric Fourier Transform`` in
Bujack et al., Proc. of ICCA9, covering most versions in the literature. We
showed which constraints are additionally necessary to obtain certain features
like linearity, a scaling, or a shift theorem. In this paper we extend the
former results by a convolution theorem.