title: Spin clusters and conformal field theory

abstract:
  We study numerically the fractal dimensions and the bulk three-point
connectivity for the spin clusters of the Q-state Potts model in two dimensions
with $1\leq Q\leq 4$. We check that the usually invoked correspondence between
FK clusters and spin clusters works at the level of fractal dimensions.
However, the fine structure of the conformal field theories describing critical
clusters first manifests at the level of the three-point connectivities.
Contrary to what recently found for FK clusters, no obvious relation emerges
for generic Q between the spin cluster connectivity and the structure constants
obtained from analytic continuation of the minimal model ones. The numerical
results strongly suggest then that spin and FK clusters are described by
conformal field theories with different realizations of the color symmetry of
the Potts model.


title:
Study of the flux effect on nuclear pressure vessel steel by measurement
  of magnetic properties

abstract:
  Since Reactor Pressure Vessel steels are ferromagnetic, they provide a
convenient means to monitor changes in the mechanical properties of the
material upon irradiation with high energy particles, by measuring their
magnetic properties. Here, we discuss the correlation between these two
properties (i.e. mechanical and magnetic properties) and microstructure, by
studying the flux effect on the nuclear pressure vessel steel used in reactors
currently under construction in Argentina. Charpy-V notched specimens of this
steel were irradiated in the RA1 experimental reactor at 275{\deg}C with two
lead factors (LFs), 93 and 183. The magnetic properties were studied by means
of DC magnetometry and ferromagnetic resonance. The results show that the
coercive field and magnetic anisotropy spatial distribution are sensitive to
the LF and can be explained by taking into account the evolution of the
microstructure with this parameter. The saturation magnetization shows a
dominant dependence on the accumulated damage. Consequently, the mentioned
techniques are suitable to estimate the degradation of the reactor vessel
steel.


title:
Interference alignment using finite and dependent channel extensions:
  the single beam case

abstract:
  Vector space interference alignment (IA) is known to achieve high degrees of
freedom (DoF) with infinite independent channel extensions, but its performance
is largely unknown for a finite number of possibly dependent channel
extensions. In this paper, we consider a $K$-user $M_t \times M_r$ MIMO
interference channel (IC) with arbitrary number of channel extensions $T$ and
arbitrary channel diversity order $L$ (i.e., each channel matrix is a generic
linear combination of $L$ fixed basis matrices). We study the maximum DoF
achievable via vector space IA in the single beam case (i.e. each user sends
one data stream). We prove that the total number of users $K$ that can
communicate interference-free using linear transceivers is upper bounded by
$NL+N^2/4$, where $N = \min\{M_tT, M_rT \}$. An immediate consequence of this
upper bound is that for a SISO IC the DoF in the single beam case is no more
than $\min\left\{\sqrt{ 5K/4}, L + T/4\right\}$. When the channel extensions
are independent, i.e. $ L$ achieves the maximum $M_r M_t T $, we show that this
maximum DoF lies in $[M_r+M_t-1, M_r+M_t]$ regardless of $T$. Unlike the
well-studied constant MIMO IC case, the main difficulty is how to deal with a
hybrid system of equations (zero-forcing condition) and inequalities (full rank
condition). Our approach combines algebraic tools that deal with equations with
an induction analysis that indirectly considers the inequalities.


title: Congruences of the fork extensions. II. The congruence gamma

abstract:
  G. Cz\'edli and E.\,T. Schmidt introduced in 2012 the fork extension.
Continuing from Part I, we investigate the congruences of a fork extension.
This paper has been merged with Part I, under the title Congruences of fork
extensions of slim semimodular lattices, see arXiv: 1307.8404


title:
Sequential Monte Carlo Methods for High-Dimensional Inverse Problems: A
  case study for the Navier-Stokes equations

abstract:
  We consider the inverse problem of estimating the initial condition of a
partial differential equation, which is only observed through noisy
measurements at discrete time intervals. In particular, we focus on the case
where Eulerian measurements are obtained from the time and space evolving
vector field, whose evolution obeys the two-dimensional Navier-Stokes equations
defined on a torus. This context is particularly relevant to the area of
numerical weather forecasting and data assimilation. We will adopt a Bayesian
formulation resulting from a particular regularization that ensures the problem
is well posed. In the context of Monte Carlo based inference, it is a
challenging task to obtain samples from the resulting high dimensional
posterior on the initial condition. In real data assimilation applications it
is common for computational methods to invoke the use of heuristics and
Gaussian approximations. The resulting inferences are biased and not
well-justified in the presence of non-linear dynamics and observations. On the
other hand, Monte Carlo methods can be used to assimilate data in a principled
manner, but are often perceived as inefficient in this context due to the
high-dimensionality of the problem. In this work we will propose a generic
Sequential Monte Carlo (SMC) sampling approach for high dimensional inverse
problems that overcomes these difficulties. The method builds upon Markov chain
Monte Carlo (MCMC) techniques, which are currently considered as benchmarks for
evaluating data assimilation algorithms used in practice. In our numerical
examples, the proposed SMC approach achieves the same accuracy as MCMC but in a
much more efficient manner.


title: Dynamically generated flat-band phases in optical kagome lattices

abstract:
  Motivated by recent advances in the realization of complex two-dimensional
optical lattices, we investigate theoretically the quantum transport of
ultracold fermions in an optical kagome lattice. In particular, we focus on its
extensively degenerate localized states (flat band). By loading fermions in a
partial region of the lattice and depleting the mobile atoms at the far
boundary of the initially unoccupied region, we find a dynamically generated
flat-band insulator, which is also a population-inverted state. We further show
that inclusion of weak repulsion leads to a dynamical stripe phase for
two-component fermions in a similar setup. Finally, by preparing a topological
insulating state in a partially occupied kagome lattice, we find that the
topological chiral current decays but exhibits an interesting oscillating
dynamics during the nonequilibrium transport. Given the broad variety of
lattice geometries supporting localized or topological states, our work
suggests new possibilities to use geometrical effects and their dynamics in
atomtronic devices.


title: The Case for a Muon Collider Higgs Factory

abstract:
  We propose the construction of a compact Muon Collider Higgs Factory. Such a
machine can produce up to \sim 14,000 at 8\times 10^{31} cm^-2 sec^-1 clean
Higgs events per year, enabling the most precise possible measurement of the
mass, width and Higgs-Yukawa coupling constants.


title:
Solutions of Conformal Israel-Stewart Relativistic Viscous Fluid
  Dynamics

abstract:
  We use symmetry arguments developed by Gubser to construct the first
radially-expanding explicit solutions of the Israel-Stewart formulation of
hydrodynamics. Along with a general semi-analytical solution, an exact
analytical solution is given which is valid in the cold plasma limit where
viscous effects from shear viscosity and the relaxation time coefficient are
important. The radially expanding solutions presented in this paper can be used
as nontrivial checks of numerical algorithms employed in hydrodynamic
simulations of the quark-gluon plasma formed in ultra-relativistic heavy ion
collisions. We show this explicitly by comparing such analytic and
semi-analytic solutions with the corresponding numerical solutions obtained
using the MUSIC viscous hydrodynamics simulation code.


title: Transient ageing in fractional Brownian and Langevin equation motion

abstract:
  Stochastic processes driven by stationary fractional Gaussian noise, that is,
fractional Brownian motion and fractional Langevin equation motion, are usually
considered to be ergodic in the sense that, after an algebraic relaxation, time
and ensemble averages of physical observables coincide. Recently it was
demonstrated that fractional Brownian motion and fractional Langevin equation
motion under external confinement are transiently non-ergodic---time and
ensemble averages behave differently---from the moment when the particle starts
to sense the confinement. Here we show that these processes also exhibit
transient ageing, that is, physical observables such as the time averaged mean
squared displacement depend on the time lag between the initiation of the
system at time $t=0$ and the start of the measurement at the ageing time $t_a$.
In particular, it turns out that for fractional Langevin equation motion the
ageing dependence on $t_a$ is different between the cases of free and confined
motion. We obtain explicit analytical expressions for the aged moments of the
particle position as well as the time averaged mean squared displacement and
present a numerical analysis of this transient ageing phenomenon.


title: Separation coordinates, moduli spaces and Stasheff polytopes

abstract:
  We show that the orthogonal separation coordinates on the sphere $S^n$ are
naturally parametrised by the real version of the Deligne-Mumford-Knudsen
moduli space $\bar M_{0,n+2}(R)$ of stable curves of genus zero with $n+2$
marked points. We use the combinatorics of Stasheff polytopes tessellating
$\bar M_{0,n+2}(R)$ to classify the different canonical forms of separation
coordinates and deduce an explicit construction of separation coordinates and
St\"ackel systems from the mosaic operad structure on $\bar M_{0,n+2}(R)$.


title: Hyperquarks and bosonic preon bound states

abstract:
  In a model in which leptons, quarks, and the recently introduced hyperquarks
are built up from two fundamental spin 1/2 preons, the standard model weak
gauge bosons emerge as preon bound states. In addition, the model predicts a
host of new composite gauge bosons, in particular those responsible for
hyperquark and proton decay. Their presence entails a left-right symmetric
extension of the standard model weak interactions and a scheme for a partial
and grand unification of nongravitational interactions based on respectively
the effective gauge groups SU(6)_P and SU(9)_G. This leads to a prediction of
the Weinberg angle at low energies in good agreement with experiment.
Furthermore, using evolution equations for the effective coupling strengths, we
calculate the partial and grand unification scales, the hyperquark mass scale,
as well as the mass and decay rate of the lightest hyperhadron.


title:
Modeling Human Decision-making in Generalized Gaussian Multi-armed
  Bandits

abstract:
  We present a formal model of human decision-making in explore-exploit tasks
using the context of multi-armed bandit problems, where the decision-maker must
choose among multiple options with uncertain rewards. We address the standard
multi-armed bandit problem, the multi-armed bandit problem with transition
costs, and the multi-armed bandit problem on graphs. We focus on the case of
Gaussian rewards in a setting where the decision-maker uses Bayesian inference
to estimate the reward values. We model the decision-maker's prior knowledge
with the Bayesian prior on the mean reward. We develop the upper credible limit
(UCL) algorithm for the standard multi-armed bandit problem and show that this
deterministic algorithm achieves logarithmic cumulative expected regret, which
is optimal performance for uninformative priors. We show how good priors and
good assumptions on the correlation structure among arms can greatly enhance
decision-making performance, even over short time horizons. We extend to the
stochastic UCL algorithm and draw several connections to human decision-making
behavior. We present empirical data from human experiments and show that human
performance is efficiently captured by the stochastic UCL algorithm with
appropriate parameters. For the multi-armed bandit problem with transition
costs and the multi-armed bandit problem on graphs, we generalize the UCL
algorithm to the block UCL algorithm and the graphical block UCL algorithm,
respectively. We show that these algorithms also achieve logarithmic cumulative
expected regret and require a sub-logarithmic expected number of transitions
among arms. We further illustrate the performance of these algorithms with
numerical examples. NB: Appendix G included in this version details minor
modifications that correct for an oversight in the previously-published proofs.
The remainder of the text reflects the published work.


title:
Interaction effects on atomic laboratory trapped Bose-Einstein
  condensates

abstract:
  We discuss the effect of inter-atoms interactions on the condensation
temperature $T_c$ of an atomic laboratory trapped Bose-Einstein condensate. We
show that, in the mean-field Hartree-Fock and semiclassical approximations,
interactions produce a shift $\Delta T_{c}/T_{c}^{0} \approx b_1
(a/\lambda_{T_c}) + b_2 (a/\lambda_{T_c})^2 + \psi[a/\lambda_{T_c}]$ with $a$
the s-wave scattering length, $\lambda_T$ the thermal wavelength and
$\psi[a/\lambda_{T_c}]$ a non-analytic function such that $\psi[0] = \psi'[0] =
\psi"[0] = 0$ and $|\psi"'[0]| = \infty$. Therefore, with no more assumptions
than Hartree-Fock and semiclassical approximations, interaction effecs are
perturbative to second order in $a/\lambda_{T_c}$ and the expected
non-perturbativity of physical quantities at critical temperature appears only
to third order. We compare this finding with different results by other
authors, which are based on more than the Hartree-Fock and semiclassical
approximations. Moreover, we obtain an analytical estimation for $b_2 \simeq
18.8$ which improves a previous numerical result. We also discuss how the
discrepancy between $b_2$ and the empirical value of $b_2 = 46 \pm 5$ may be
explained with no need to resort to beyond-mean field effects.


title: Searching for Black Holes in Space - the key role of X-ray observations

abstract:
  Although General Relativity had provided the physical basis of black holes,
evidence for their existence had to await the Space Era when X-ray observations
first directed the attention of astronomers to the unusual binary stars Cygnus
X-1 and A0620-00. Subsequently, a number of faint Ariel 5 and Uhuru sources,
mainly at high Galactic latitude, were found to lie close to bright Seyfert
galaxies,suggesting the nuclear activity in AGN might also be driven by
accretion in the strong gravity of a black hole. Detection of rapid X-ray
variability with EXOSAT later confirmed that the accreting object in AGN was
almost certainly a supermassive black hole.


title: $E_8$ Bundles and Rigidity

abstract:
  In this paper, we establish rigidity and vanishing theorems for Dirac
operators twisted by $E_8$ bundles.


title:
Universality and quantization of the power to heat ratio in
  nano-granular systems

abstract:
  We study heating and dissipation effects in granular nanosystems in the
regime of weak coupling between the grains. We focus on the cotunneling regime
and solve the heat-dissipation problem in an array of grains exactly. We show
that the power to heat ratio has a universal quantized value, which is
geometrically protected: it depends only on the number of grains.


title: Higher Order Variational Integrators: a polynomial approach

abstract:
  We reconsider the variational derivation of symplectic partitioned
Runge-Kutta schemes. Such type of variational integrators are of great
importance since they integrate mechanical systems with high order accuracy
while preserving the structural properties of these systems, like the
symplectic form, the evolution of the momentum maps or the energy behaviour.
Also they are easily applicable to optimal control problems based on mechanical
systems as proposed in Ober-Bl\"obaum et al. [2011].
  Following the same approach, we develop a family of variational integrators
to which we refer as symplectic Galerkin schemes in contrast to symplectic
partitioned Runge-Kutta. These two families of integrators are, in principle
and by construction, different one from the other. Furthermore, the symplectic
Galerkin family can as easily be applied in optimal control problems, for which
Campos et al. [2012b] is a particular case.


title:
Confluences of the Painleve equations, Cherednik algebras and q-Askey
  scheme

abstract:
  In this paper we produce seven new algebras as confluences of the Cherednik
algebra of type \check{C_1}C_1 and we characterise their
spherical-sub-algebras.
  The limit of the spherical sub-algebra of the Cherednik algebra of type
\check{C_1}C_1 is the monodromy manifold of the Painlev\'e VI equation. Here we
prove that by considering the limits of the spherical sub-algebras of our new
confluent algebras, one obtains the monodromy manifolds of all other Painlev\'e
differential equations. Moreover, we introduce confluent versions of the
Zhedanov algebra and prove that each of them (quotiented by their Casimir) is
isomorphic to the corresponding spherical sub-algebra of our new confluent
Cherednik algebras. We show that in the basic representation our confluent
Zhedanov algebras act as symmetries of certain elements of the q-Askey scheme,
thus setting a stepping stone towards the solution of the open problem of
finding the corresponding quantum algebra for each element of the q-Askey
scheme.
  These results establish a new link between the theory of the Painlev\'e
equations and the theory of the q-Askey scheme and shed light on the reasons
behind the occurrence of special polynomials in the Painlev\'e theory.


title: Compact Object Formation and the Supernova Explosion Engine

abstract:
  When a massive star ends its life, its core collapses, forming a neutron star
or black hole and producing some of the most energetic explosions in the
universe. Core-collapse supernovae and long-duration gamma-ray bursts are the
violent signatures of compact remnant formation. As such, both fields are
intertwined and, coupled with theory, observations of transients can help us
better understand compact remnants just as neutron star and black hole
observations can constrain the supernova and gamma-ray burst engine. We review
these ties in this paper.


title: R2 vertices for the effective ggH theory

abstract:
  We list all possible R2 Feynman rules needed in NLO computations involving
couplings of Higgs and gluons mediated by an infinitely heavy top loop. They
provide the rational contribution generated by the (d-4)-dimensional part of
the amplitude, paving the way for four-dimensional automatic NLO methods in
Higgs phenomenology.


title: Generative, Fully Bayesian, Gaussian, Openset Pattern Classifier

abstract:
  This report works out the details of a closed-form, fully Bayesian,
multiclass, openset, generative pattern classifier using multivariate Gaussian
likelihoods, with conjugate priors. The generative model has a common
within-class covariance, which is proportional to the between-class covariance
in the conjugate prior. The scalar proportionality constant is the only plugin
parameter. All other model parameters are intergated out in closed form. An
expression is given for the model evidence, which can be used to make plugin
estimates for the proportionality constant. Pattern recognition is done via the
predictive likeihoods of classes for which training data is available, as well
as a predicitve likelihood for any as yet unseen class.


title: Student Variability in Learning Advanced Physics

abstract:
  Learning of advanced physics, requires a combination of empirical, conceptual
and theoretical understanding. Students use a combination of these approaches
to learn new material. Each student has different prior knowledge and will
master new material at a different pace. However, conventional classroom
teaching usually does not accommodate the different learning paces of students.
To both, study and address this issue, we developed an iterative Online
Learning Machine (iOLM), which provides new learning content to each student
based on their individual learning pace and tracks their progress individually.
The iOLM learning module was implemented using server side web software (php)
to supplement the undergraduate course in electromagnetic waves for majors in
physics in their second year. This approach follows the hybrid online learning
model. Students had to complete a section of the course using iOLM, which was
only presented online. The data obtained for this class showed a wide spread of
learning paces, ranging from 0.1 to 0.5, where 1 is the maximum pace allowed by
iOLM and 0 the lowest. The mean was mu=0.25, with a standard deviation of
sigma=0.12. While the pretest showed a positive correlation between the
student's pace and performance, the postest had zero correlation, indicating
that giving more time and content to weaker students allows them to catch up.


title: Online Communities: Visualization and Formalization

abstract:
  Online communities have increased in size and importance dramatically over
the last decade. The fact that many communities are online means that it is
possible to extract information about these communities and the connections
between their members much more easily using software tools, despite their
potentially very large size. The links between members of the community can be
presented visually and often this can make patterns in the structure of
sub-communities immediately obvious. The links and structures of layered
communities can also be formalized to gain a better understanding of their
modelling. This paper explores these links with some specific examples,
including visualization of these relationships and a formalized model of
communities using the Z notation. It also considers the development of such
communities within the Community of Practice social science framework. Such
approaches may be applicable for communities associated with cybersecurity and
could be combined for a better understanding of their development.


title: Ruled surfaces asymptotically normalized

abstract:
  We consider a skew ruled surface $\Phi$ in the Euclidean space $E^{3}$ and
relative normalizations of it, so that the relative normals at each point lie
in the corresponding asymptotic plane of $\Phi$. We call such relative
normalizations and the resulting relative images of $\Phi$ \emph{asymptotic}.
We determine all ruled surfaces and the asymptotic normalizations of them, for
which $\Phi$ is a relative sphere (proper or inproper) or the asymptotic image
degenerates into a curve. Moreover we study the sequence of the ruled surfaces
${\Psi_{i}}_{i\in \mathbb{N}}$, where $\Psi_{1}$ is an asymptotic image of
$\Phi$ and $\Psi_{i}$, for $i\geq2$, is an asymptotic image of $\Psi_{i-1}$. We
conclude the paper by the study of various properties concerning some vector
fields, which are related with $\Phi$.


title: Hermitian Young Operators

abstract:
  Starting from conventional Young operators we construct Hermitian operators
which project orthogonally onto irreducible representations of the (special)
unitary group.


title:
Electromagnetic and gravitational radiation from the coherent
  oscillation of electron-positron pairs and fields

abstract:
  Integrating equations of particle-number and energy-momentum conservation and
Maxwell field equations, we study the oscillation and drift of electron and
positron pairs coherently with fields after these pairs are produced in
external electromagnetic fields. From the electric current of oscillating
pairs, we obtain the energy spectrum of electromagnetic dipole radiation. This
narrow spectrum is so peculiar that the detection of such radiation can
identify pair production and oscillation in strong laser fields. We also obtain
the energy spectrum of gravitational quadrapole radiation from the
energy-momentum tensor of oscillating pairs and fields. Thus, we discuss the
generation of gravitational waves on the basis of rapid development of strong
laser fields.


title:
A new class of large claim size distributions: Definition, properties,
  and ruin theory

abstract:
  We investigate a new natural class $\mathcal{J}$ of probability distributions
modeling large claim sizes, motivated by the `principle of one big jump'.
Though significantly more general than the (sub-)class of subexponential
distributions $\mathcal{S}$, many important and desirable structural properties
can still be derived. We establish relations to many other important large
claim distribution classes (such as $\mathcal{D}$, $\mathcal{S}$,
$\mathcal{L}$, $\mathcal {K}$, $\mathcal{OS}$ and $\mathcal{OL}$), discuss the
stability of $\mathcal{J}$ under tail-equivalence, convolution, convolution
roots, random sums and mixture, and then apply these results to derive a
partial analogue of the famous Pakes-Veraverbeke-Embrechts theorem from ruin
theory for $\mathcal{J}$. Finally, we discuss the (weak) tail-equivalence of
infinitely-divisible distributions in $\mathcal{J}$ with their L\'{e}vy
measure.


title:
Seeding supermassive black holes with a non-vortical dark-matter
  subcomponent

abstract:
  A perfect irrotational fluid with the equation of state of dust, Irrotational
Dark Matter (IDM), is incapable of virializing and instead forms a
cosmoskeleton of filaments with supermassive black holes at the joints. This
stark difference from the standard cold dark matter (CDM) scenario arises
because IDM must exhibit potential flow at all times, preventing shell-crossing
from occurring. This scenario is applicable to general non-oscillating
scalar-field theories with a small sound speed. Our model of combined IDM and
CDM components thereby provides a solution to the problem of forming the
observed billion-solar-mass black holes at redshifts of six and higher. In
particular, as a result of the reduced vortical flow, the growth of the black
holes is expected to be more rapid at later times as compared to the standard
scenario.


title: Framings and dilations

abstract:
  The notion of framings, recently emerging in P. G. Casazza, D. Han, and D. R.
Larson, Frames for Banach spaces, in {\em The functional and harmonic analysis
of wavelets and frames} (San Antonio, TX, 1999), {\em Contemp. Math}. {\bf 247}
(1999), 149-182 as generalization of the reconstraction formula generated by
pairs of dual frames, is in this note extended substantially. This calls on
refining the basic dilation results which still being in the flavor of {\em
th\'eor\`eme principal} of B. Sz-Nagy go much beyond it.


title: Frequency cavity pulling induced by a single semiconductor quantum dot

abstract:
  We investigate the emission properties of a single semiconductor quantum dot
deterministically coupled to a confined optical mode in the weak coupling
regime. A strong pulling, broadening and narrowing of the cavity mode emission
is evidenced when changing the spectral detuning between the emitter and the
cavity. These features are theoretically accounted for by considering the
phonon assisted emission of the quantum dot transition. These observations
highlight a new situation for cavity quantum electrodynamics involving
spectrally broad emitters.


title: Asymptotes and Perfect Curves

abstract:
  We develop a method for computing all the {\it generalized asymptotes} of a
real plane algebraic curve $\cal C$ over $\Bbb C$ implicitly defined by an
irreducible polynomial $f(x,y)\in {\Bbb R}[x,y]$. The approach is based on the
notion of perfect curve introduced from the concepts and results presented in
Blasco, A., P\'erez-D\'{\i}az, S. (2013). {\it Asymptotic Behavior of an
Implicit Algebraic Plane Curve}. arxiv.org/abs/1302.2522v2.


title:
A prototype low-background multiwire proportional chamber for measuring
  alphas and low-energy betas

abstract:
  A prototype multiwire proportional chamber (MWPC) was developed to
demonstrate the feasibility of constructing a radiopure time projection chamber
with MWPC track readout to assay materials for alpha- and beta-emitting surface
contaminants for future rare-event-search experiments as well as other
scientific fields. The design features and assembly techniques described here
are motivated by the position and energy resolution required to reconstruct
alpha and beta tracks while efficiently rejecting backgrounds. Results from a
test setup using an $^{55}$Fe x-ray source indicate excellent operational
stability and a near-ideal energy resolution of 15.8% FWHM at 5.89 keV and a
gas gain of $\sim$10$^{4}$.


title: Integral Cayley graphs and groups

abstract:
  We solve two open problems regarding the classification of certain classes of
Cayley graphs with integer eigenvalues. We first classify all finite groups
that have a "non-trivial" Cayley graph with integer eigenvalues, thus solving a
problem proposed by Abdollahi and Jazaeri. The notion of Cayley integral groups
was introduced by Klotz and Sander. These are groups for which every Cayley
graph has only integer eigenvalues. In the second part of the paper, all Cayley
integral groups are determined.


title: The highest redshift gamma-ray bursts

abstract:
  I review the searches for gamma-ray bursts at very high redshift. Although
the numbers of GRBs known at z>6 remain few, even small samples can provide
information about early star and galaxy formation in the universe which is very
hard to obtain by any other means.


title:
Phenomenology of Supersymmetric Models with a Symmetry-Breaking Seesaw
  Mechanism

abstract:
  We explore phenomenological implications of the minimal supersymmetric
standard model (MSSM) with a strong supersymmetry breaking trilinear term.
Supersymmetry breaking can trigger electroweak symmetry breaking via a
symmetry-breaking seesaw mechanism, which can lead to a low-energy theory with
multiple composite Higgs bosons. In this model, the electroweak phase
transition can be first-order for some generic values of parameters.
Furthermore, there are additional sources of CP violation in the Higgs sector.
This opens the possibility of electroweak baryogenesis in the strongly coupled
MSSM. The extended Higgs dynamics can be discovered at Large Hadron Collider or
at a future linear collider.


title: Canonical approach to the closed string noncommutativity

abstract:
  We consider the closed string moving in the weakly curved background and its
totally T-dualized background. Using T-duality transformation laws, we find the
structure of the Poisson brackets in the T-dual space corresponding to the
fundamental Poisson brackets in the original theory. From this structure we
obtain that the commutative original theory is equivalent to the
non-commutative T-dual theory, whose Poisson brackets are proportional to the
background fluxes times winding and momenta numbers. The non-commutative theory
of the present article is more nongeometrical then T-folds and in the case of
three space-time dimensions corresponds to the nongeometric space-time with
$R$-flux.


title: From intersection local time to the Rosenblatt process

abstract:
  The Rosenblatt process was obtained by Taqqu (1975) from convergence in
distribution of partial sums of strongly dependent random variables. In this
paper we give a particle picture approach to the Rosenblatt process with the
help of intersection local time and white noise analysis, and discuss measuring
its long range dependence by means of a number called dependence exponent.


title:
Transmembrane and Antimicrobial Peptides. Hydrophobicity, Amphiphilicity
  and Propensity to Aggregation

abstract:
  Development of the new antimicrobial agents against antibiotic resistance
pathogens is the nowadays challenge. Antimicrobial peptides (AMP) occur as
important defence agents in many organisms and offer a viable alternative to
conventional antibiotics. Therefore they have become increasingly recognized in
current research as templates for prospective antibiotic agents. The efficient
designing of the new antimicrobials on the basis of antimicrobial peptides
requires comprehensive knowledge on those general physical-chemical
characteristics which allow to differ antimicrobial peptides from non-active
against microbs ones. According to supposed mechanisms of action, AMP interact
with and physically disrupt the bacterial membranes. Consequently,
hydrophobicity, amphiphilicity and intrinsic aggregation propensities are
considered as such major characteristics of the peptide, which determine the
results of peptide-membrane interactions. For some kind of peptides such
characteristics as hydrophobicity, amphiphilicity and aggregation bias
determines their ability to compose transmembrane domain of the membrane
protein, whilst for others the same properties are respond for their
antimicrpobial activity, i.e. give them ability of membrane permeability and
its damage. In this review we analyze the data about hydrophobicity,
amphiphilicity and intrinsic aggregation propensities available in literature
in order to compare antimicrobial and transmembrane peptides and show what is
the common and what is the difference in this respect between them.


title: Applications of Holography to Strongly Coupled Plasmas

abstract:
  We study several observables related to heavy quarks in strongly coupled
plasmas using the gauge/gravity correspondence. Besides the AdS_5 space dual to
N=4 supersymmetric Yang-Mills theory we consider large classes of theories
obtained from various deformations of the AdS_5 space. Among them are theories
that solve equations of motion of a 5-dimensional Einstein-Hilbert-scalar
action. Specifically, we calculate the screening distance of a heavy
quark-antiquark pair moving at constant velocity through the plasma, the
running coupling defined via the free energy of such a static pair, and the
energy radiation from a heavy quark forced into a circular motion in the
plasma. We find that these observables show universal behaviour in large
classes of theories. The screening distance in these classes of theories, that
is the maximal distance for which a heavy quark-antiquark pair is bound, is
found to be bounded from below by its value in N=4 super Yang-Mills theory.


title: Drinfeld modules, Frobenius endomorphisms, and CM-liftings

abstract:
  We give a global description of the Frobenius elements in the division fields
of Drinfeld modules of rank $2$. We apply this description to derive a
criterion for the splitting modulo primes of a class of non-solvable
polynomials, and to study the frequency with which the reductions of Drinfeld
modules have small endomorphism rings. We also generalize some of these results
to higher rank Drinfeld modules and prove CM-lifting theorems for Drinfeld
modules.


title: Human and Automatic Evaluation of English-Hindi Machine Translation

abstract:
  For the past 60 years, Research in machine translation is going on. For the
development in this field, a lot of new techniques are being developed each
day. As a result, we have witnessed development of many automatic machine
translators. A manager of machine translation development project needs to know
the performance increase/decrease, after changes have been done in his system.
Due to this reason, a need for evaluation of machine translation systems was
felt. In this article, we shall present the evaluation of some machine
translators. This evaluation will be done by a human evaluator and by some
automatic evaluation metrics, which will be done at sentence, document and
system level. In the end we shall also discuss the comparison between the
evaluations.


title: Levy's phenomenon for entire functions of several variables

abstract:
  For entire functions $f(z)=\sum_{n=0}^{+\infty}a_nz^n, z\in {\Bbb C},$ P.
L${\rm \acute{e}}$vy (1929) established that in the classical Wiman's
inequality $M_f(r)\leq\mu_f(r)\times $ $\times(\ln\mu_f(r))^{1/2+\varepsilon},\
\varepsilon>0,$ which holds outside a set of finite logarithmic measure, the
constant 1/2 can be replaced almost surely in some sense, by 1/4; here
  $M_f(r)=\max\{|f(z)|\colon |z|=r\},\ \mu_f(r)=\max\{|a_n|r^n\colon n\geq0\},\
r>0. $ In this paper we prove that the phenomenon discovered by P.
L${\rm\acute{e}}$vy holds also in the case of Wiman's inequality for entire
functions of several variables, which gives an affirmative answer to the
question of A. A. Goldberg and M. M. Sheremeta (1996) on the possibility of
this phenomenon.


title:
Studies of the decays $B^+ \to p \bar p h^+$ and observation of $B^+ \to
  \kern 0.1em\bar{\kern -0.1em\Lambda}(1520)p$

abstract:
  Dynamics and direct $C\P$ violation in three-body charmless decays of charged
$B$ mesons to a proton, an antiproton and a light meson (pion or kaon) are
studied using data, corresponding to an integrated luminosity of 1.0$
{\,fb}^{-1}$, collected by the ${LHCb}$ experiment in $pp$ collisions at a
center-of-mass energy of 7 TeV. Production spectra are determined as a function
of Dalitz-plot and helicity variables. The forward-backward asymmetry of the
light meson in the $p\bar p$ rest frame is measured. No significant $C\P$
asymmetry in $B^+ \to p \bar p K^+$ decay is found in any region of the Dalitz
plane. We present the first observation of the decay $B^+ \to \kern
0.1em\bar{\kern -0.1em\Lambda}(1520)(\to K^+\bar p)p$ near the $K^+\bar p$
threshold and measure $\mathcal{B}(B^+ \to \kern 0.1em\bar{\kern
-0.1em\Lambda}(1520)p)=(3.9^{+1.0}_{-0.9} (\mathrm{stat})\pm0.1
(\mathrm{syst})\pm0.3 (\mathrm{BF}))\times 10^{-7}$, where BF denotes the
uncertainty on secondary branching fractions.


title: Rotating black hole in Einstein and pure Lovelock gravity

abstract:
  We obtain rotating black hole metric for higher dimensional Einstein and pure
Lovelock gravity by employing two independent and well motivated methods. One
is based on the principle of incorporation of Newtonian acceleration for
timelike motion while no acceleration for null motion. The other is the well
known Newman-Janis alogrithm that converts a static black hole into a rotating
one through a complex transformation. It turns out that both the methods give
the same metric which for Einst of the eour pure Lovelock metricein black hole
is an exact vacuum solution while for pure Lovelock black hole it satisfies the
vacuum equation in the leading order. However it shares all the physical
properties with the well known Kerr black hole.


title: The Universe as a Process of Unique Events

abstract:
  We describe a new class of models of quantum space-time based on energetic
causal sets and show that under natural conditions space-time emerges from
them. These are causal sets whose causal links are labelled by energy and
momentum and conservation laws are applied at events. The models are motivated
by principles we propose govern microscopic physics which posit a fundamental
irreversibility of time. One consequence is that each event in the history of
the universe has a distinct causal relationship to the rest; this requires a
novel form of dynamics which an be applied to uniquely distinctive events. We
hence introduce a new kind of deterministic dynamics for a causal set in which
new events are generated from pairs of progenitor events by a rule which is
based on extremizing the distinctions between causal past sets of events. This
dynamics is asymmetric in time, but we find evidence from numerical simulations
of a 1+1 dimensional model, that an effective dynamics emerges which restores
approximate time reversal symmetry. Energetic causal set models differ from
other spacetime-free causal set approaches, e.g. Ref. [1] proposed causal sets
based on quantum information processing systems, and Ref. [2] proposed causal
sets constructed out of standard model particles. Finally we also present a
natural twistorial representation of energetic causal sets.


title: Decisive test of color coherence in proton-nucleus collisions at the LHC

abstract:
  Proton-nucleus collisions (p+A) at LHC energies provide a rigorous test of
the Color Glass Condensate (CGC), a model proposed to describe the high energy
limit of Quantum Chromodynamics. In the CGC the average multiplicity of charged
particles at midrapidity in p+A collisions depends logarithmically on the
number of participants, $N_{part}$. In contrast, the Wounded Nucleon Model
(WNM) of independent nucleon-nucleon scatterings, verified at RHIC energies,
predicts that multiplicity in p+A depends linearly on $N_{part}$. We argue that
for the first time, the dependence of mean multiplicity on $N_{part}$ in p+A
collisions at LHC energies can single out a model of particle production, thus
offering a stringent test of the CGC and the WNM. Based on this observation we
propose a novel experimental test of color coherence in p+A collisions.


title: The world is discrete

abstract:
  We argue that the scale-free spectrum that is observed in the cosmic
microwave background is the result of a phase transition in the early universe.
The observed tilt of the spectrum, which has been measured to be 0.04, is shown
to be equal to the anomalous scaling dimension of the correlation function. The
phase transition replaces inflation as the mechanism that produces this
spectrum. The tilt further indicates that there is a fundamental small length
scale in nature that we have not yet observed in any other way.


title: 6th International Symposium on Attention in Cognitive Systems 2013

abstract:
  This volume contains the papers accepted at the 6th International Symposium
on Attention in Cognitive Systems (ISACS 2013), held in Beijing, August 5,
2013. The aim of this symposium is to highlight the central role of attention
on various kinds of performance in cognitive systems processing. It brings
together researchers and developers from both academia and industry, from
computer vision, robotics, perception psychology, psychophysics and
neuroscience, in order to provide an interdisciplinary forum to present and
communicate on computational models of attention, with the focus on
interdependencies with visual cognition. Furthermore, it intends to investigate
relevant objectives for performance comparison, to document and to investigate
promising application domains, and to discuss visual attention with reference
to other aspects of AI enabled systems.


title: On string density at the origin

abstract:
  In
  [V. Barcilon Explicit solution of the inverse problem for a vibrating string.
J. Math. Anal. Appl. {\bf 93} (1983) 222-234] two boundary value problems were
considered generated by the differential equation of a string $$
y^{\prime\prime}+\lambda p(x)y=0, \ \ 0\leq x \leq L<+\infty \eqno{(*)} $$ with
continuous real function $p(x)$ (density of the string) and the boundary
conditions $y(0)=y(L)=0$ the first problem and $y^{\prime}(0)=y(L)=0$ the
second one. In the above paper the following formula was stated $$
p(0)={1}{L^2\mu_1}\mathop{\prod}\limits_{n=1}^{\infty}{\lambda_n^2}{\mu_n
\mu_{n+1}} \eqno{(**)} $$ where $\{\lambda_k\}_{k=1}^{\infty}$ is the spectrum
of the first boundary value problem and $\{\mu_k\}_{k=1}^{\infty}$ of the
second one. Rigorous proof of (**) was given in [C.-L. Shen On the Barcilon
formula for the string equation with a piecewise continuous density function.
Inverse Problems {\bf 21}, (2005) 635--655] under more restrictive conditions
of piecewise continuity of $p^{\prime}(x)$. In this paper (**) was deduced
using $$ p(0)=\lim\limits_{\lambda\to
+\infty}({\phi(L,-\lambda)}{\lambda^{{1}{2}}\psi(L,-\lambda)})^2 \eqno{(***})
$$ where $\phi(x,\lambda)$ is the solution of (*) which satisfies the boundary
conditions $\phi(0)-1=\phi^{\prime}(0)=0$ and $\psi(x,\lambda)$ is the solution
of (*) which satisfies $\psi(0)=\psi^{\prime}(0)-1=0$.
  In our paper we prove that (***) is true for the so-called M.G. Krein's
string which may have any nondecreasing mass distribution function $M(x)$ with
finite nonzero $M^{\prime}(0)$. Also we show that (**) is true for a wide class
of strings including those for which $M(x)$ is a singular function, i.e.
$M^{\prime}(x)=p(x)\mathop{=}\limits^{a.e.}0$.


title:
Can the coincidence problem be solved by a cosmological model of coupled
  dark energy and dark matter?

abstract:
  Motivated by the cosmological constant and the coincidence problems, we
consider a cosmological model where the dark sectors are interacting together
through a phenomenological decay law $\dot{\rho}_{\Lambda}=Q\rho_{\Lambda}^n$
in a FRW spacetime with spatial curvature. We show that the only value of $n$
for which the late-time matter energy density to dark energy density ratio
($r_m=\rho_m/\rho_{\Lambda}$) is constant (which could provide an explanation
to the coincidence problem) is $n=3/2$. For each value of $Q$, there are two
distinct solutions. One of them involves a spatial curvature approaching zero
at late times ($\rho_k\approx0$) and is stable when the interaction is weaker
than a critical value ${Q_0=-\sqrt{32\pi G/c^2}}$. The other one allows for a
non-negligible spatial curvature ($\rho_k\napprox0$) at late times and is
stable when the interaction is stronger than $Q_0$. We constrain the model
parameters using various observational data (SNeIa, GRB, CMB, BAO, OHD). The
limits obtained on the parameters exclude the regions where the cosmological
constant problem is significantly ameliorated and do not allow for a completely
satisfying explanation for the coincidence problem.


title: Electroweak limits on physics beyond the Standard Model

abstract:
  We briefly review the global Standard Model fit to electroweak precision
data, and discuss the status of electroweak constraints on new interactions. We
follow a general effective Lagrangian approach to obtain model-independent
limits on the dimension-six operators, as well as on several common new physics
extensions.


title: Computation on Elliptic Curves with Complex Multiplication

abstract:
  We give the complete list of possible torsion subgroups of elliptic curves
with complex multiplication over number fields of degree 1-13. Additionally we
describe the algorithm used to compute these torsion subgroups and its
implementation.


title:
Relativistic calculations of the U91+(1s)-U92+ collision using the
  finite basis set of cubic Hermite splines on a lattice in coordinate space

abstract:
  A new method for solving the time-dependent two-center Dirac equation is
developed. The approach is based on the using of the finite basis of cubic
Hermite splines on a three-dimensional lattice in the coordinate space. The
relativistic calculations of the excitation and charge-transfer probabilities
in the U91+(1s)-U92+ collisions in two and three dimensional approaches are
performed. The obtained results are compared with our previous calculations
employing the Dirac-Sturm basis sets [I.I. Tupitsyn et al., Phys. Rev. A 82,
042701 (2010)]. The role of the negative-energy Dirac spectrum is investigated
within the monopole approximation.


title:
Disruption of a Red Giant Star by a Supermassive Black Hole and the Case
  of PS1-10jh

abstract:
  The development of a new generation of theoretical models for tidal
disruptions is timely, as increasingly diverse events are being captured in
surveys of the transient sky. Recently, Gezari et al. reported a discovery of a
new class of tidal disruption events: the disruption of a helium-rich stellar
core, thought to be a remnant of a red giant (RG) star. Motivated by this
discovery and in anticipation of others, we consider tidal interaction of an RG
star with a supermassive black hole (SMBH) which leads to the stripping of the
stellar envelope and subsequent inspiral of the compact core toward the black
hole. Once the stellar envelope is removed the inspiral of the core is driven
by tidal heating as well as the emission of gravitational radiation until the
core either falls into the SMBH or is tidally disrupted. In the case of tidal
disruption candidate PS1-10jh we find that there is a set of orbital solutions
at high eccentricities in which the tidally stripped hydrogen envelope is
accreted by the SMBH before the helium core is disrupted. This places the RG
core in a portion of parameter space where strong tidal heating can lift the
degeneracy of the compact remnant and disrupt it before it reaches the tidal
radius. We consider how this sequence of events explains the puzzling absence
of the hydrogen emission lines from the spectrum of PS1-10jh and gives rise to
its other observational features.


title: Nonlinear group survival in Kimura's model for the evolution of altruism

abstract:
  Establishing the conditions that guarantee the spreading or the sustenance of
altruistic traits in a population is the main goal of intergroup selection
models. Of particular interest is the balance of the parameters associated to
group size, migration and group survival against the selective advantage of the
non-altruistic individuals. Here we use Kimura's diffusion model of intergroup
selection to determine those conditions in the case the group survival
probability is a nonlinear non-decreasing function of the proportion of
altruists in a group. In the case this function is linear, there are two
possible steady states which correspond to the non-altruistic and the
altruistic phases. At the discontinuous transition line separating these phases
there is a non-ergodic coexistence phase. For a continuous concave survival
function, we find an ergodic coexistence phase that occupies a finite region of
the parameter space in between the altruistic and the non-altruistic phases,
and is separated from these phases by continuous transition lines. For a convex
survival function, the coexistence phase disappears altogether but a bistable
phase appears for which the choice of the initial condition determines whether
the evolutionary dynamics leads to the altruistic or the non-altruistic steady
state.


title: A Naturally Light Sterile neutrino in an Asymmetric Dark Matter Model

abstract:
  A recently proposed asymmetric mirror dark matter model where the mirror
sector is connected with the visible one by a right handed neutrino portal, is
shown to lead naturally to a 3+1 active-sterile neutrino spectrum, if the
portal consists only of two right handed neutrinos. At the tree level the model
has four massless neutrino states, three active and one sterile. The active
neutrinos pick up tiny masses via the minimal radiative inverse seesaw
mechanism at the one loop level. The loop effects also generate the large solar
and atmospheric mixings, as well as the observed reactor mixing for certain
range of parameters of the model. The dominant contribution to the sterile
neutrino mass ($\sim$ eV) arises from the gravitationally induced dimension-5
operators. Generating active-sterile mixing requires a two Higgs doublet
extension of SM and a small mixing between the ordinary and mirror Higgs
fields, which occurs naturally in mirror models.


title:
Multi-horizon solar radiation forecasting for Mediterranean locations
  using time series models

abstract:
  Considering the grid manager's point of view, needs in terms of prediction of
intermittent energy like the photovoltaic resource can be distinguished
according to the considered horizon: following days (d+1, d+2 and d+3), next
day by hourly step (h+24), next hour (h+1) and next few minutes (m+5 e.g.).
Through this work, we have identified methodologies using time series models
for the prediction horizon of global radiation and photovoltaic power. What we
present here is a comparison of different predictors developed and tested to
propose a hierarchy. For horizons d+1 and h+1, without advanced ad hoc time
series pre-processing (stationarity) we find it is not easy to differentiate
between autoregressive moving average (ARMA) and multilayer perceptron (MLP).
However we observed that using exogenous variables improves significantly the
results for MLP . We have shown that the MLP were more adapted for horizons
h+24 and m+5. In summary, our results are complementary and improve the
existing prediction techniques with innovative tools: stationarity, numerical
weather prediction combination, MLP and ARMA hybridization, multivariate
analysis, time index, etc.


title: Microscopic origin of spin-orbital separation in Sr2CuO3

abstract:
  Recently performed resonant inelastic x-ray scattering experiment (RIXS) at
the copper L3 edge in the quasi-1D Mott insulator Sr2CuO3 has revealed a
significant dispersion of a single orbital excitation (orbiton). This large and
unexpected orbiton dispersion has been explained using the concept of
spin-orbital fractionalization in which orbiton, which is intrinsically coupled
to the spinon in this material, liberates itself from the spinon due to the
strictly 1D nature of its motion. Here we investigate this mechanism in detail
by: (i) deriving the microscopic spin-orbital superexchange model from the
charge transfer model for the CuO3 chains in Sr2CuO3, (ii) mapping the orbiton
motion in the obtained spin-orbital model into a problem of a single hole
moving in an effective half-filled antiferromagnetic chain t-J model, and (iii)
solving the latter model using the exact diagonalization and obtaining the
orbiton spectral function. Finally, the RIXS cross section is calculated based
on the obtained orbiton spectral function and compared with the RIXS
experiment.


title:
Internal Bremsstrahlung Signature of Real Scalar Dark Matter and
  Consistency with Thermal Relic Density

abstract:
  A gamma-ray excess from the galactic center consistent with line emission
around 130 GeV was recently found in the Fermi-LAT data. Although the Fermi-LAT
Collaboration has not confirmed its significance, such a signal would be a
clear signature of Dark Matter annihilation. Until now, there have been many
attempts to explain the excess by Dark Matter. However these efforts tend to
give too-small cross sections into photons if consistency with the correct
thermal relic density of Dark Matter is required. In this letter, we consider a
simple Yukawa interaction that can be compatible with both aspects and show
which parameters are favored.


title: Separable State Decompositions for a Class of Mixed States

abstract:
  We study certain quantum states for which the PPT criterion is both
sufficient and necessary for separability. A class of $n\times n$ bipartite
mixed states is presented and the conditions of PPT for these states are
derived. The separable pure state decompositions of these states are explicitly
constructed when they are PPT.


title: Slow sedimentation and deformability of charged lipid vesicles

abstract:
  The study of vesicles in suspension is important to understand the
complicated dynamics exhibited by cells in vivo and in vitro. We developed a
computer simulation based on the boundary-integral method to model the three
dimensional gravity-driven sedimentation of charged vesicles towards a flat
surface. The membrane mechanical behavior was modeled using the Helfrich
Hamiltonian and near incompressibility of the membrane was enforced via a model
which accounts for the thermal fluctuations of the membrane. The simulations
were verified and compared to experimental data obtained using suspended
vesicles labelled with a fluorescent probe, which allows visualization using
fluorescence microscopy and confers the membrane with a negative surface
charge. The electrostatic interaction between the vesicle and the surface was
modeled using the linear Derjaguin approximation for a low ionic concentration
solution. The sedimentation rate as a function of the distance of the vesicle
to the surface was determined both experimentally and from the computer
simulations. The gap between the vesicle and the surface, as well as the shape
of the vesicle at equilibrium were also studied. It was determined that
inclusion of the electrostatic interaction is fundamental to accurately predict
the sedimentation rate as the vesicle approaches the surface and the size of
the gap at equilibrium, we also observed that the presence of charge in the
membrane increases its rigidity.


title: Magnitude and size evolution of bulgeless galaxies

abstract:
  We examine the magnitude and size evolution of bulgeless (discs with no-bulge
or pseudo-bulge) galaxies up to z~0.9 in rest-frame B-band. Their evolution is
compared to that of normal-discs (discs with classical-bulge). The study is
done for luminous sources (M_B<=-20) in two equal-volume redshift-bins
(0.4<=z<0.77 and 0.77<=z<1.0) and a local range (0.02<=z<0.05). The mean
surface-brightness, from z_{mean}=0.89 to z_{mean}=0.04, shows a dimming of
0.79 mag for bulgeless galaxies and 1.16 mag for normal-discs. The
characteristic magnitude, M_B^*, shows an increase of 0.55-mag for bulgeless
galaxies and 0.95-mag for normal-discs. Both dimming and faintness observed
since z~0.9 are more pronounced for the normal-discs by ~0.4-mag. The
size-distribution is log-normal and both bulgeless and normal-discs show a
slight increase in the mean value from z_{mean}=0.89 to z_{mean}=0.04. The
proportion of bulgeless galaxies in the full disc sample undergoes a
considerable decline with decrease in redshift. This along with the larger
dimming and faintness seen for normal-discs suggests that some fraction of the
bulgeless sources switch to the normal-disc morphology with time. To ascertain
the validity of studying morphology in the optical, the properties of the
galaxies observed in both rest-frame B and I-band are compared. The common
sample is more luminous in the I-band but the sizes are larger in the B-band
for more than 74 % of the sources. The variation in the sersic-index values of
the galaxies in the two rest-bands is minor enough to have any affect on the
morphological classification.


title:
Comment on Damping Force in the Transit-time Method of Optical
  Stochastic Cooling

abstract:
  In this brief report we pointed at mistake in paper A. Zholents, Damping
Force in the Transit-Time Method of Optical Stochastic Cooling, PRLST. Mar 1,
2012. 2 pp. Published in Phys.Rev.ST Accel. Beams 15 (2012) 032801.


title: Critical behavior of the contact process on small-world networks

abstract:
  We investigate the role of clustering on the critical behavior of the contact
process (CP) on small-world networks using the Watts-Strogatz (WS) network
model with an edge rewiring probability p. The critical point is well predicted
by a homogeneous cluster-approximation for the limit of vanishing clustering (p
close to 1). The critical exponents and dimensionless moment ratios of the CP
are in agreement with those predicted by the mean-field theory for any p > 0.
This independence on the network clustering shows that the small-world property
is a sufficient condition for the mean-field theory to correctly predict the
universality of the model. Moreover, we compare the CP dynamics on WS networks
with rewiring probability p = 1 and random regular networks and show that the
weak heterogeneity of the WS network slightly changes the critical point but
does not alter other critical quantities of the model.


title:
Pion production in nucleon-nucleon collisions in chiral effective field
  theory with Delta(1232)-degrees of freedom

abstract:
  A calculation of the pion-production operator up to next-to-next-to-leading
order for s-wave pions is performed within chiral effective field theory. In
the previous study [Phys. Rev. C 85, 054001 (2012)] we discussed the
contribution of the pion-nucleon loops at the same order. Here we extend that
study to include explicit Delta degrees of freedom and the 1/m_N^2 corrections
to the pion-production amplitude. Using the power counting scheme where the
Delta-nucleon mass difference is of the order of the characteristic momentum
scale in the production process, we calculate all tree-level and loop diagrams
involving Delta up to next-to-next-to-leading order. The long-range part of the
Delta loop contributions is found to be of similar size to that from the
pion-nucleon loops which supports the counting scheme. The net effect of
pion-nucleon and Delta loops is expected to play a crucial role in
understanding of the neutral pion production data.


title:
Sliding Windows and Persistence: An Application of Topological Methods
  to Signal Analysis

abstract:
  We develop in this paper a theoretical framework for the topological study of
time series data. Broadly speaking, we describe geometrical and topological
properties of sliding window (or time-delay) embeddings, as seen through the
lens of persistent homology. In particular, we show that maximum persistence at
the point-cloud level can be used to quantify periodicity at the signal level,
prove structural and convergence theorems for the resulting persistence
diagrams, and derive estimates for their dependency on window size and
embedding dimension. We apply this methodology to quantifying periodicity in
synthetic data sets, and compare the results with those obtained using
state-of-the-art methods in gene expression analysis. We call this new method
SW1PerS which stands for Sliding Windows and 1-dimensional Persistence Scoring.


title:
The evolution of planetary nebulae. VIII. True expansion rates and
  visibility times

abstract:
  The visibility time of planetary nebulae (PNe) in stellar systems is an
essential quantity for estimating the size of a PN population in the context of
general population studies. For instance, it enters directly into the PN death
rate determination. The basic ingredient for determining visibility times is
the typical nebular expansion velocity, as a suited average over all PN sizes
of a PN population within a certain volume or stellar system. The true
expansion speed of the outer nebular edge of a PN is, however, not accessible
by spectroscopy -- a difficulty that we surmount by radiation-hydrodynamics
modelling. We find a mean true expansion velocity of 42 km/s, i.e. nearly twice
as high as the commonly adopted value to date. Accordingly, the time for a PN
to expand to a radius of, say 0.9 pc, is only 21000 +/- 5000 years. This
visibility time of a PN holds for all central star masses since a nebula does
not become extinct as the central star fades. There is, however, a dependence
on metallicity in the sense that the visibility time becomes shorter for lower
nebular metal content. With the higher expansion rate of PNe derived here we
determined their local death-rate density as (1.4 +/- 0.5) x E-12 PN pc^{-3}
yr^{-1}, using the local PN density advocated by Frew (2008).


title: Symmetry energy impact in simulations of core-collapse supernovae

abstract:
  We present a review of a broad selection of nuclear matter equations of state
(EOSs) applicable in core-collapse supernova studies. The large variety of
nuclear matter properties, such as the symmetry energy, which are covered by
these EOSs leads to distinct outcomes in supernova simulations. Many of the
currently used EOS models can be ruled out by nuclear experiments, nuclear
many-body calculations, and observations of neutron stars. In particular the
two classical supernova EOS describe neutron matter poorly. Nevertheless, we
explore their impact in supernova simulations since they are commonly used in
astrophysics. They serve as extremely soft and stiff representative nuclear
models. The corresponding supernova simulations represent two extreme cases,
e.g., with respect to the protoneutron star (PNS) compactness and shock
evolution. Moreover, in multi-dimensional supernova simulations EOS differences
have a strong effect on the explosion dynamics. Because of the extreme
behaviors of the classical supernova EOSs we also include DD2, a relativistic
mean field EOS with density-dependent couplings, which is in satisfactory
agreement with many current nuclear and observational constraints. This is the
first time that DD2 is applied to supernova simulations and compared with the
classical supernova EOS. We find that the overall behaviour of the latter EOS
in supernova simulations lies in between the two extreme classical EOSs. As
pointed out in previous studies, we confirm the impact of the symmetry energy
on the electron fraction. Furthermore, we find that the symmetry energy becomes
less important during the post bounce evolution, where conversely the symmetric
part of the EOS becomes increasingly dominating, which is related to the high
temperatures obtained. Moreover, we study the possible impact of quark matter
at high densities and light nuclear clusters at low and intermediate dens


title:
Thermal Properties, Sizes, and Size Distribution of Jupiter-Family
  Cometary Nuclei

abstract:
  We present results from SEPPCoN, an on-going Survey of the Ensemble Physical
Properties of Cometary Nuclei. In this report we discuss mid-infrared
measurements of the thermal emission from 89 nuclei of Jupiter-family comets
(JFCs). All data were obtained in 2006 and 2007 with the Spitzer Space
Telescope. For all 89 comets, we present new effective radii, and for 57 comets
we present beaming parameters. Thus our survey provides the largest compilation
of radiometrically-derived physical properties of nuclei to date. We conclude
the following. (a) The average beaming parameter of the JFC population is
1.03+/-0.11, consistent with unity, and indicating low thermal inertia. (b) The
known JFC population is not complete even at 3 km radius, and even for comets
with perihelia near ~2 AU. (c) We find that the JFC nuclear cumulative size
distribution (CSD) has a power-law slope of around -1.9. (d) This power-law is
close to that derived from visible-wavelength observations, suggesting that
there is no strong dependence of geometric albedo with radius. (e) The observed
CSD shows a hint of structure with an excess of comets with radii 3 to 6 km.
(f) Our CSD is consistent with an intrinsic distribution that lacks many
sub-kilometer objects.


title: Universal graphs and universal permutations

abstract:
  Let $X$ be a family of graphs and $X_n$ the set of $n$-vertex graphs in $X$.
A graph $U^{(n)}$ containing all graphs from $X_n$ as induced subgraphs is
called $n$-universal for $X$. Moreover, we say that $U^{(n)}$ is a proper
$n$-universal graph for $X$ if it belongs to $X$. In the present paper, we
construct a proper $n$-universal graph for the class of split permutation
graphs. Our solution includes two ingredients: a proper universal 321-avoiding
permutation and a bijection between 321-avoiding permutations and symmetric
split permutation graphs. The $n$-universal split permutation graph constructed
in this paper has $4n^3$ vertices, which means that this construction is
order-optimal.


title: The Magneto-Rotational Decay Instability in Keplerian Disks

abstract:
  The saturation of the magnetorotational (MRI) instability in thin Keplerian
disks through three wave resonant interactions is introduced and discussed.
That mechanism is a natural generalization of the fundamental decay instability
discovered five decades ago for infinite, homogeneous and immovable plasmas.
The decay instability relies on the energy transfer from the MRI to stable slow
Alfv'en-Coriolis (AC) as well as magnetosonic (MS) waves. A second order forced
Duffing amplitude equation for the initially unstable MRI as well as two first
order equations for the other two waves are derived. The solutions of those
equations exhibit bounded bursty nonlinear oscillations for the MRI as well as
unbounded growth for the linearly stable slow AC and MS perturbations, thus
giving rise to the magneto-rotational decay instability (MRDI).


title:
Almost critical well-posedness for nonlinear wave equation with
  $Q_{\mu\nu}$ null forms in 2D

abstract:
  In this paper we prove an optimal local well-posedness result for the 1+2
dimensional system of nonlinear wave equations (NLW) with quadratic null-form
derivative nonlinearities $Q_{\mu\nu}$. The Cauchy problem for these equations
is known to be ill-possed for data in the Sobolev space $H^s$ with $s<5/4$ for
all the basic null-forms, except $Q_0$. However, the scaling analysis predicts
local well-posedness all the way to the critical regularity of $s_c=1$.
Following Gr\"{u}nrock's result for the quadratic derivative NLW, we consider
initial data in the Fourier-Lebesgue spaces $\^{H}_s^r$, which coincide with
the Sobolev spaces of the same regularity for $r=2$, but scale like lower
regularity Sobolev spaces for $1<r<2$. Here we obtain local well-posedness for
the range $s>1+{1}{r}$, $1<r\leq 2$, which at one extreme coincides with
$H^{{3}{2}+}$ Sobolev space result, while at the other extreme establishes
local well-posedness for the model null-form problem for the almost critical
Fourier-Lebesgue space $\^{H}_{2+}^{1+}$. Using appropriate multiplicative
properties of the solution spaces and relying on bilinear estimates for the
$Q_{\mu\nu}$ forms, we prove almost critical local well-posedness for the Ward
wave map problem as well.


title:
Probing the anisotropy of the Milky Way gaseous halo: Sight-lines toward
  Mrk 421 and PKS2155-304

abstract:
  (Abridged) We recently found that the halo of the Milky Way contains a large
reservoir of warm-hot gas that contains a large fraction of the missing baryons
from the Galaxy. The average physical properties of this circumgalactic medium
(CGM) are determined by combining average absorption and emission measurements
along several extragalactic sightlines. However, there is a wide distribution
of both, the halo emission measure and the \ovii column density, suggesting
that the Galactic warm-hot gaseous halo is anisotropic. We present {\it Suzaku}
observations of fields close to two sightlines along which we have precise
\ovii absorption measurements with \chandran. The column densities along these
two sightlines are similar within errors, but we find that the emission
measures are different. Therefore the densities and pathlengths in the two
directions must be different, providing a suggestive evidence that the warm-hot
gas in the CGM of the Milky Way is not distributed uniformly. However, the
formal errors on derived parameters are too large to make such a claim. The
average density and pathlength of the two sightlines are similar to the global
averages, so the halo mass is still huge, over 10 billion solar masses. With
more such studies, we will be able to better characterize the CGM anisotropy
and measure its mass more accurately. We also show that the Galactic disk makes
insignificant contribution to the observed \ovii absorption; a similar
conclusion was also reached independently about the emission measure. We
further argue that any density inhomogeneity in the warm-hot gas, be it from
clumping, from the disk, or from a non-constant density gradient, would
strengthen our result in that the Galactic halo path-length and the mass would
become larger than what we estimate here. As such, our results are conservative
and robust.


title: Inequalities for sums of Green potentials and Blaschke products

abstract:
  We study inequalities for the infima of Green potentials on a compact subset
of an arbitrary domain in the complex plane. The results are based on a new
representation of the pseudohyperbolic farthest-point distance function via a
Green potential. We also give applications to sharp inequalities for the
supremum norms of Blaschke products.


title:
Scalable control of graphene growth on 4H-SiC C-face using decomposing
  silicon nitride masks

abstract:
  Patterning of graphene is key for device fabrication. We report a way to
increase or reduce the number of layers in epitaxial graphene grown on the
C-face (000-1) of silicon carbide by the deposition of a 120 nm to 150nm-thick
silicon nitride (SiN) mask prior to graphitization. In this process we find
that areas covered by a Si-rich SiN mask have one to four more layers than
non-masked areas. Conversely N-rich SiN decreases the thickness by three
layers. In both cases the mask decomposes before graphitization is completed.
Graphene grown in masked areas show good quality as observed by Raman
spectroscopy, atomic force microscopy (AFM) and transport data. By tailoring
the growth parameters selective graphene growth and sub-micron patterns have
been obtained.


title:
Asymptotic Expansions and Bondi Positivity in Higher Dimensional
  Relativity

abstract:
  The positivity of the Bondi mass has been proven in 4 dimensions, but in
higher dimensions the issue remains open. The formalism of the present paper
has been developed to investigate this and is well suited to the higher
dimensional case. At null infinity, we make asymptotic expansions of the metric
components in conformal Gaussian null coordinates, and use the vacuum Einstein
equations to solve for the expansion coefficients. We find simple coordinate
formulae for the Bondi mass, news and flux in terms of the expansion
coefficients of the metric components. We also make expansions of the generator
of an asymptotic symmetry and obtain expressions for its expansion coefficients
in terms of those of the metric components. We make a spinorial asymptotic
expansion of a solution to the Dirac equation in the four dimensional case, and
use it to give a clean proof that the Bondi mass is positive in four
dimensions. The generalisation to higher dimensions has been investigated, but
not yet resolved: indeed, the spinor mass appears to be divergent in the higher
dimensional case, because of terms which appear to be singular in the limit at
infinity. Such apparently singular terms are common in many of our
calculations, but can generally be shown to be zero before the limit is taken.
However, it is not yet clear this can be done in the case of the spinor mass in
higher dimensions, so further investigation is required.


title:
Intrinsic structure of liquid surface and capillary waves on the Density
  Functional Theory

abstract:
  Two different theories are used to understand the liquid-vapor interfaces:
the Van der Waals theory and the capillary waves theory. But comparing both
come up a problem of interpretation of the interface density profiles obtained,
for example, with the Density Functional Theory (DFT). As a consequence emerge
the question of how the surface fluctuations are included on traditional
density profiles (usually named equilibrium density profiles). Last years, new
insights on the role of capillary waves were possible by analyzing X-ray
reflectivity experiments and performing computer simulations of liquids with
low melting temperature. In particular, the density profile exhibits a layering
structure which is considered a key property to elucidate a new interpretation
of those profiles as intrinsic density profiles. This dissertation aims to
investigate these questions within the DFT using simple fluids with a pairwise
interactions that reproduce important phase-diagram properties of liquid
metals. Two generics questions were explored: the relevance of Fisher-Widom
line and the role of capillary waves on the nature of interface obtained with
approximations WDA and FMT. It hypothesized the existence of a density profile
with strong layering properties whose structure is reduced by capillary waves.
Then the effect of surface fluctuations is described by introducing an
effective transversal size which imposes a limitation of the spectrum of
surface fluctuations incorporated on the DFT. However, an explicit methodology
to unfreeze the capillary waves over a postulated intrinsic profile exempt of
surface fluctuations was proven still a challenge. As a consequence it
suggested that other previous results describing the liquid surface using the
equilibrium DFT may conduct to unphysical properties.


title: Polynomials with integer coefficients and their zeros

abstract:
  We study several related problems on polynomials with integer coefficients.
This includes the integer Chebyshev problem, and the Schur problems on means of
algebraic numbers. We also discuss interesting applications to approximation by
polynomials with integer coefficients, and to the growth of coefficients for
polynomials with roots located in prescribed sets. The distribution of zeros
for polynomials with integer coefficients plays an important role in all of
these problems.


title: Kinematic Analysis Towards Glueballs

abstract:
  In the present work a consistent kinematic-based framework for glueball
states is proposed. It relates the glueball, the Pomeron, QCD lattice
calculations, the $0^{++}$ scalar states $f_0(1710)$ and $\chi_{c0}(1P)$, the
$2^{++}$ states $f_J(2220)$ and $\chi_{c2}(2P)$, the baryonic charmed state
$\Xi_c^+(2645)$.


title: Expected discrepancy for zeros of random algebraic polynomials

abstract:
  We study asymptotic clustering of zeros of random polynomials, and show that
the expected discrepancy of roots of a polynomial of degree $n$, with not
necessarily independent coefficients, decays like $\sqrt{\log n/n}$. Our proofs
rely on discrepancy results for deterministic polynomials, and order statistics
of a random variable. We also consider the expected number of zeros lying in
certain subsets of the plane, such as circles centered on the unit
circumference, and polygons inscribed in the unit circumference.


title: Thermal conductivity of one-, two- and three-dimensional carbon

abstract:
  Carbon atoms can form structures in one, two, and three dimensions due to its
unique chemical versatility. In terms of thermal conductivity, carbon
polymorphs cover a wide range from very low values with amorphous carbon to
very high values with diamond, carbon nanotubes and graphene. Schwarzites are a
class of three-dimensional fully covalent sp$^2$-bonded carbon polymorphs, with
the same local chemical environment as graphene and carbon nanotubes, but
negative Gaussian curvature. We calculate the thermal conductivity of a (10,0)
carbon nanotube, graphene, and two schwarzites with different curvature, by
molecular dynamics simulations based on the Tersoff empirical potential. We
find that schwarzites present a thermal conductivity two orders of magnitude
smaller than nanotubes and graphene. The reason for such large difference is
explained by anharmonic lattice dynamics calculations, which show that phonon
group velocities and mean free paths are much smaller in schwarzites than in
nanotubes and graphene. Their reduced thermal conductivity, in addition to
tunable electronic properties, indicate that schwarzites could pave the way
towards all-carbon thermoelectric technology with high conversion efficiency.


title: Neutrino Mass and Dark Matter in light of recent AMS-02 results

abstract:
  We study a simple extension of the Standard Model supplemented by an
electroweak triplet scalar field to accommodate small neutrino masses by the
type-II seesaw mechanism, while an additional singlet scalar field can play the
role of cold dark matter (DM) in our Universe. This DM candidate is leptophilic
for a wide range of model parameter space, and the lepton flux due to its
annihilation carries information about the neutrino mass hierarchy. Using the
recently released high precision data on positron fraction and flux from the
AMS-02 experiment, we examine the DM interpretation of the observed positron
excess in our model for two kinematically distinct scenarios with the DM and
triplet scalar masses (a) non-degenerate ($m_{\rm DM}\gg m_{\Delta}$), and (b)
quasi-degenerate ($m_{\rm DM} \simeq m_\Delta$). We find that a good fit to the
AMS-02 data can be obtained in both cases (a) and (b) with a normal hierarchy
of neutrino masses, while the inverted hierarchy case is somewhat disfavored.
Although we require a larger boost factor for the normal hierarchy case, this
is still consistent with the current upper limits derived from Fermi-LAT and
IceCube data for case (a). Moreover, the absence of an excess anti-proton flux
as suggested by PAMELA data sets an indirect upper limit on the DM-nucleon
spin-independent elastic scattering cross section which is stronger than the
existing DM direct detection bound from LUX in the AMS-02 preferred DM mass
range.


title:
Reverse Triangle Inequalities for Riesz Potentials and Connections with
  Polarization

abstract:
  We study reverse triangle inequalities for Riesz potentials and their
connection with polarization. This work generalizes inequalities for sup norms
of products of polynomials, and reverse triangle inequalities for logarithmic
potentials. The main tool used in the proofs is the representation for a power
of the farthest distance function as a Riesz potential of a unit Borel measure.


title:
Non-Gorenstein isolated singularities of graded countable Cohen-Macaulay
  type

abstract:
  In this paper we show a partial answer the a question of C. Huneke and G.
Leuschke (2003): Let R be a standard graded Cohen-Macaulay ring of graded
countable Cohen-Macaulay representation type, and assume that R has an isolated
singularity. Is R then necessarily of graded finite Cohen-Macaulay
representation type? In particular, this question has an affirmative answer for
standard graded non-Gorenstein rings as well as for standard graded Gorenstein
rings of minimal multiplicity. Along the way, we obtain a partial
classification of graded Cohen-Macaulay rings of graded countable
Cohen-Macaulay type.


title:
On the Intrinsic Continuum Linear Polarization of Classical Be Stars
  during Disk Growth and Dissipation

abstract:
  We investigate the intrinsic continuum linear polarization from axisymmetric
density distributions of gas surrounding classical Be stars during the
formation and dissipation of their circumstellar disks. We implement a Monte
Carlo calculation of the Stokes parameters with the use of the non-LTE
radiative transfer code of Sigut & Jones (2007) to reproduce the continuous
polarimetric spectra of classical Be stars. The scattering of light in the
nonspherical circumstellar envelopes of classical Be stars produces a distinct
polarization signature that can be used to study the physical nature of the
scattering environment. In this paper, we highlight the utility of polarimetric
measurements as important diagnostics in the modeling of these systems. We
illustrate the effects of using self-consistent calculation of the thermal
structure of the circumstellar gas on the characteristic wavelength-dependence
of the polarization spectrum. In showing that the principal features of the
polarization spectrum originate from different parts of the disk, we emphasize
the capability of polarimetric observations to trace the evolution of the disk
on critical scales. We produce models that approximate the disk formation and
dissipation periods and illustrate how the polarimetric properties of these
systems can have a pivotal role in determining the mechanism for mass decretion
from the central star.


title: Difference Sequence Spaces Derived by Using Generalized Means

abstract:
  This paper deals with new sequence spaces $X(r, s, t ;\Delta) $ for $X\in
\{l_\infty, c, c_0\}$ defined by using generalized means and difference
operator. It is shown that these spaces are complete normed linear spaces and
the spaces $X(r, s, t ;\Delta)$ for $X\in \{c, c_0\}$ have Schauder basis.
Furthermore, the $\alpha$-, $\beta$-, $\gamma$- duals of these sequence spaces
are computed and also established necessary and sufficient conditions for
matrix transformations from $X(r, s, t ;\Delta)$ to $X$.


title:
A unified sparse matrix data format for efficient general sparse
  matrix-vector multiply on modern processors with wide SIMD units

abstract:
  Sparse matrix-vector multiplication (spMVM) is the most time-consuming kernel
in many numerical algorithms and has been studied extensively on all modern
processor and accelerator architectures. However, the optimal sparse matrix
data storage format is highly hardware-specific, which could become an obstacle
when using heterogeneous systems. Also, it is as yet unclear how the wide
single instruction multiple data (SIMD) units in current multi- and many-core
processors should be used most efficiently if there is no structure in the
sparsity pattern of the matrix. We suggest SELL-C-sigma, a variant of Sliced
ELLPACK, as a SIMD-friendly data format which combines long-standing ideas from
General Purpose Graphics Processing Units (GPGPUs) and vector computer
programming. We discuss the advantages of SELL-C-sigma compared to established
formats like Compressed Row Storage (CRS) and ELLPACK and show its suitability
on a variety of hardware platforms (Intel Sandy Bridge, Intel Xeon Phi and
Nvidia Tesla K20) for a wide range of test matrices from different application
areas. Using appropriate performance models we develop deep insight into the
data transfer properties of the SELL-C-sigma spMVM kernel. SELL-C-sigma comes
with two tuning parameters whose performance impact across the range of test
matrices is studied and for which reasonable choices are proposed. This leads
to a hardware-independent ("catch-all") sparse matrix format, which achieves
very high efficiency for all test matrices across all hardware platforms.


title:
Dwarf Galaxy Planes: the discovery of symmetric structures in the Local
  Group

abstract:
  Both major galaxies in the Local Group (LG) are surrounded by thin planes of
mostly co-orbiting satellite galaxies, the vast polar structure (VPOS) around
the Milky Way (MW) and the Great Plane of Andromeda (GPoA) around M31. We
summarize the current knowledge concerning these structures and compare their
relative orientations and properties in a common coordinate system. The
existence of coherent satellite structures motivates an investigation of the
distribution of the more distant non-satellite galaxies in the LG. This results
in the discovery of two planes (diameters of 1-2 Mpc) which contain almost all
nearby non-satellite galaxies. The two LG planes are surprisingly symmetric,
inclined by only 20 deg relative to the galactic disc of M31, similarly thin
(heights of ~60 kpc) and have near-to-identical offsets from the MW and M31.
They are inclined relative to each other by 35 deg. Comparing the plane
orientations with each other and with additional features indicates an intimate
connection between the VPOS and the GPoA. They are both polar to the MW, have
similar orbital directions and are inclined by ~45 deg relative to each other.
The Magellanic Stream approximately aligns with the VPOS and the GPoA, but also
shares its projected position and line-of-sight velocity trend with the
dominating structure of non-satellite dwarf galaxies. The proper motion of M31
indicates a prograde orbit of the MW-M31 system, the VPOS and the GPoA. The
alignment with other features such as the Supergalactic Plane and the
over-density in hypervelocity stars are discussed as well. We end with a
summary of proposed scenarios trying to explain the LG galaxy structures as
either originating from cosmological structures or from tidal debris of a past
galaxy encounter. There currently exists no full detailed model which
satisfactorily explains the existence of the thin symmetric LG planes.
(abridged)


title:
Simulating extremely metal-poor gas and DLA metal content at redshift
  z=7

abstract:
  We present the first theoretical study of metals in damped Ly-alpha (DLA)
systems at redshift z=7. The features of cold, primordial gas are studied by
means of N-body, hydro, chemistry simulations, including atomic and molecular
non-equilibrium chemistry, cooling, star formation for population III and
population II-I regimes, stellar evolution, cosmic metal spreading according to
proper yields (for He, C, O, Si, Fe, Mg, S, etc.) and lifetimes, and feedback
effects. Theoretical expectations are then compared to recently available
constraints from DLA observations. We find that DLA galaxies at z=7 account for
10 per cent of the whole galaxy population and for most of the metal-poor
galaxies at these epochs. About 7 per cent of these DLA galaxies contain purely
pristine material and 34 per cent of them consist of very weakly polluted gas,
being, therefore, suitable candidate s as population III sites. The remaining
59 per cent are enriched above ~10^{-4} Zsun. Additionally, DLA candidates
appear to have: gas masses <~2x10^8 Msun; very low star formation rate,
~10^{-3} - 10^{-2} Msun/yr (significantly weaker than late-time counterparts);
mean molecular fractions covering a fairly wide range, x_mol~10^{-3}- 10^{-6};
typical metallicities Z<~3x10^{-3}Zsun and HI column densities NHI>~3x10^{20}
cm^{-2}. They present no or weak correlations between their gas mass and Z,
NHI, or x_mol; a moderate correlation between x_mol and Z, linked to the
ongoing molecular-driven star formation and metal pollution processes; a mild
anti-correlation between NHI and x_mol, due to H depletion into molecules; and
a chemical content that is subject to environmental dependencies.


title: Astropy: A Community Python Package for Astronomy

abstract:
  We present the first public version (v0.2) of the open-source and
community-developed Python package, Astropy. This package provides core
astronomy-related functionality to the community, including support for
domain-specific file formats such as Flexible Image Transport System (FITS)
files, Virtual Observatory (VO) tables, and common ASCII table formats, unit
and physical quantity conversions, physical constants specific to astronomy,
celestial coordinate and time transformations, world coordinate system (WCS)
support, generalized containers for representing gridded as well as tabular
data, and a framework for cosmological transformations and conversions.
Significant functionality is under active development, such as a model fitting
framework, VO client and server tools, and aperture and point spread function
(PSF) photometry tools. The core development team is actively making additions
and enhancements to the current code base, and we encourage anyone interested
to participate in the development of future Astropy versions.


title: Low Scale Quark-Lepton Unification

abstract:
  We investigate the possibility that quarks and leptons are unified at a low
energy scale much smaller than the grand unified scale. A simple theory for
quark-lepton unification based on the gauge group SU(4)_C X SU(2)_L X U(1)_R is
proposed. This theory predicts the existence of scalar leptoquarks which could
be produced at the Large Hadron Collider. In order to have light neutrinos
without fine tuning, their masses are generated through the inverse see-saw
mechanism.


title: Fock Parafermions and Self-Dual Representations of the Braid Group

abstract:
  We introduce and describe in second quantization a family of particle species
with \(p=2,3,\dots\) exclusion and \(\theta=2\pi/p\) exchange statistics. We
call these anyons Fock parafermions, because they are the particles naturally
associated to the parafermionic zero-energy modes, potentially realizable in
mesoscopic arrays of fractional topological insulators. Their
second-quantization description entails the concept of Fock algebra, i.e., a
Fock space endowed with a statistical multiplication that captures and
logically correlates these anyons' exclusion and exchange statistics. As a
consequence normal-ordering continues to be a well-defined operation. Because
of its relevance to topological quantum information processing, we also derive
families of self-dual representations of the braid group for any $p$, with the
Gaussian representation being a special case. The self-dual representations can
be realized in terms of local quadratic combinations of either parafermions or
Fock parafermions, an important requisite for physical implementation of
quantum logic gates.

categories: cond-mat.stat-mech math-ph math.MP quant-ph


title: Cosmic-ray Driven Outflows in Global Galaxy Disk Models

abstract:
  Galactic-scale winds are a generic feature of massive galaxies with high star
formation rates across a broad range of redshifts. Despite their importance, a
detailed physical understanding of what drives these mass-loaded global flows
has remained elusive. In this paper, we explore the dynamical impact of cosmic
rays by performing the first three-dimensional, adaptive mesh refinement
simulations of an isolated starbursting galaxy that includes a basic model for
the production, dynamics and diffusion of galactic cosmic rays. We find that
including cosmic rays naturally leads to robust, massive, bipolar outflows from
our 10^12 Msun halo, with a mass-loading factor Mout/SFR = 0.3 for our fiducial
run. Other reasonable parameter choices led to mass-loading factors above
unity. The wind is multiphase and is accelerated to velocities well in excess
of the escape velocity. We employ a two-fluid model for the thermal gas and
relativistic CR plasma and model a range of physics relevant to galaxy
formation, including radiative cooling, shocks, self-gravity, star formation,
supernovae feedback into both the thermal and CR gas, and isotropic CR
diffusion. Injecting cosmic rays into star-forming regions can provide
significant pressure support for the interstellar medium, suppressing star
formation and thickening the disk. We find that CR diffusion plays a central
role in driving superwinds, rapidly transferring long-lived CRs from the
highest density regions of the disk to the ISM at large, where their pressure
gradient can smoothly accelerate the gas out of the disk.


title: Dusty Winds: Extraplanar PAH Features of Nearby Galaxies

abstract:
  Recent observations have shown the presence of dust and molecular material in
galactic winds, but relatively little is known about the distribution of these
outflow components. To shed some light on this issue, we have used IRAC images
from the Spitzer Space Telescope archive to investigate polycyclic aromatic
hydrocarbon (PAH) emission from a sample of 16 local galaxies with known winds.
Our focus on nearby sources (median distance 8.6 Mpc) has revealed detailed PAH
structure in the winds and allowed us to measure extraplanar PAH emission. We
have identified extraplanar PAH features on scales of ~ 0.8 - 6.0 kpc. We find
a nearly linear correlation between the amount of extraplanar PAH emission and
the total infrared flux, a proxy for star formation activity in the disk. Our
results also indicate a correlation between the height of extraplanar PAH
emission and star formation rate surface density, which supports the idea of a
surface density threshold on the energy or momentum injection rate for
producing detectable extraplanar wind material.


title: A Deep Chandra X-ray Limit on the Putative IMBH in Omega Centauri

abstract:
  We report a sensitive X-ray search for the proposed intermediate mass black
hole (IMBH) in the massive Galactic cluster, Omega Centauri (NGC 5139).
Combining Chandra X-ray Observatory data from Cycles 1 and 13, we obtain a deep
(~291 ks) exposure of the central regions of the cluster. We find no evidence
for an X-ray point source near any of the cluster's proposed dynamical centers,
and place an upper limit on the X-ray flux from a central source of f_X(0.5-7.0
keV) <= 5.0x10^-16 erg cm^-2 s^-1, after correcting for absorption. This
corresponds to an unabsorbed X-ray luminosity of L_X(0.5-7.0 keV) <= 1.6x10^30
erg s^-1, for a cluster distance of 5.2 kpc, Galactic column density N_H =
1.2x10^21 cm^-2, and powerlaw spectrum with Gamma = 2.3. If a ~10^4 M_sun IMBH
resides in the cluster's core, as suggested by some stellar dynamical studies,
its Eddington luminosity would be L_Edd ~10^42 erg s^-1. The new X-ray limit
would then establish an Eddington ratio of L_X/L_Edd <~ 10^-12, a factor of ~10
lower than even the quiescent state of our Galaxy's notoriously inefficient
supermassive black hole Sgr A*, and imply accretion efficiencies as low as eta
<~ 10^-6 - 10^-8. This study leaves open three possibilities: either Omega Cen
does not harbor an IMBH or, if an IMBH does exist, it must experience very
little or very inefficient accretion.


title: Baryogenesis through split Higgsogenesis

abstract:
  We study the cosmological evolution of asymmetries in the two-Higgs doublet
extension of the Standard Model, prior to the electroweak phase transition. If
Higgs flavour-exchanging interactions are sufficiently slow, then a relative
asymmetry among the Higgs doublets corresponds to an effectively conserved
quantum number. Since the magnitude of the Higgs couplings depends on the
choice of basis in the Higgs doublet space, we attempt to formulate
basis-independent out-of-equilibrium conditions. We show that an initial
asymmetry between the Higgs scalars, which could be generated by CP violation
in the Higgs sector, will be transformed into a baryon asymmetry by the
sphalerons, without the need of $B-L$ violation. This novel mechanism of
baryogenesis through (split) Higgsogenesis is exemplified with simple scenarios
based on the out-of-equilibrium decay of heavy singlet scalar fields into the
Higgs doublets.


title: Strong Binary Pulsar Constraints on Lorentz Violation in Gravity

abstract:
  Binary pulsars are excellent laboratories to test the building blocks of
Einstein's theory of General Relativity. One of these is Lorentz symmetry which
states that physical phenomena appear the same for all inertially moving
observers. We study the effect of violations of Lorentz symmetry in the orbital
evolution of binary pulsars and find that it induces a much more rapid decay of
the binary's orbital period due to the emission of dipolar radiation. The
absence of such behavior in recent observations allows us to place the most
stringent constraints on Lorentz violation in gravity, thus verifying one of
the cornerstones of Einstein's theory much more accurately than any previous
gravitational observation.


title:
On the Intrinsic Continuum Linear Polarization of Classical Be Stars:
  The Effects of Metallicity and One-Armed Density Perturbations

abstract:
  We report on the effects of two disk properties on the continuum linear
polarization signature of classical Be stars. First, we investigate the effect
of including metallicity in computing the thermal structure of the
circumstellar gas on the resulting polarimetric Balmer jump. The Balmer jump is
a distinguishing feature of the polarization signature in these objects and, as
such, can be used as a tool for differentiating classical Be stars from similar
H alpha-emitters identified through conventional photometric techniques. We
find that although low-metallicity environments will have hotter disk
temperatures on average, the temperature change alone cannot account for the
discrepancy in the frequency of Balmer jumps between low-metallicity and
solar-metallicity stellar populations. Second, we investigate the effect of
including a global one-armed oscillation in the gas density distribution of the
modeled disk. We find that a non-axisymmetric perturbation pattern yields
discernible variations in the predicted polarization level. If these density
oscillations are present in the inner region of classical Be star disks, the
polarimetric variations should produce a periodic signature which can help
characterize the dynamical nature of the gas near the star.