title:
Local conditions separating expansion from collapse in spherically
  symmetric models with anisotropic pressures

abstract:
  We investigate spherically symmetric spacetimes with an anisotropic fluid and
discuss the existence and stability of a dividing shell separating expanding
and collapsing regions. We resort to a 3+1 splitting and obtain gauge invariant
conditions relating intrinsic spacetimes quantities to properties of the matter
source. We find that the dividing shell is defined by a generalization of the
Tolman-Oppenheimer-Volkoff equilibrium condition. The latter establishes a
balance between the pressure gradients, both isotropic and anisotropic, and the
strength of the fields induced by the Misner-Sharp mass inside the separating
shell and by the pressure fluxes. This defines a local equilibrium condition,
but conveys also a non-local character given the definition of the Misner-Sharp
mass. By the same token, it is also a generalized thermodynamical equation of
state as usually interpreted for the perfect fluid case, which now has the
novel feature of involving both the isotropic and the anisotropic stress. We
have cast the governing equations in terms of local, gauge invariant quantities
which are revealing of the role played by the anisotropic pressures and
inhomogeneous electric part of the Weyl tensor. We analyse a particular
solution with dust and radiation that provides an illustration of our
conditions. In addition, our gauge invariant formalism not only encompasses the
cracking process from Herrera and coworkers but also reveals transparently the
interplay and importance of the shear and of the anisotropic stresses.


title:
The intermediate level statistics in dynamically localized chaotic
  eigenstates

abstract:
  We demonstrate that the energy or quasienergy level spacing distribution in
dynamically localized chaotic eigenstates is excellently described by the Brody
distribution, displaying the fractional power law level repulsion. This we show
in two paradigmatic systems, namely for the fully chaotic eigenstates of the
kicked rotator at K=7, and for the chaotic eigenstates in the mixed-type
billiard system (Robnik 1983), after separating the regular and chaotic
eigenstates by means of the Poincar\'e Husimi function, at very high energies
with great statistical significance (587654 eigenstates, starting at about
1.000.000 above the ground state). This separation confirms the Berry-Robnik
picture, and is performed for the first time at such high energies.


title:
Excitation and deexcitation processes in atom-Rydberg atom collisions in
  helium-rich white dwarf atmospheres

abstract:
  We aim to show the importance of non-elastic excitation and deexcitation
processes in $\textrm{He}^{*}(n)+ \textrm{He}(1s^{2})$ collisions with the
principal quantum number $n \ge 3$ for helium-rich white dwarf atmospheres. We
compare the efficiencies of these processes with those of the known non-elastic
electron-$\textrm{He}^{*}(n)$ atom processes in the atmospheres of some DB
white dwarfs. We show that in significant parts of the considered atmospheres,
which contain weakly ionized layers (the ionization degree $\lesssim 10^{-3}$),
the influence of the studied atom-Rydberg atom processes on excited helium atom
populations is dominant or at least comparable to the influence of the
concurrent electron-$\textrm{He}^{*}(n)$-atom processes.


title:
A decomposition method with minimum communication amount for
  parallelization of multi-dimensional FFTs

abstract:
  The fast Fourier transform (FFT) is undoubtedly an essential primitive that
has been applied in various fields of science and engineering. In this paper,
we present a decomposition method for parallelization of multi-dimensional FFTs
with smallest communication amount for all ranges of the number of processes
compared to previously proposed methods. This is achieved by two distinguishing
features: adaptive decomposition and transpose order awareness. In the proposed
method, the FFT data are decomposed based on a row-wise basis that maps the
multi-dimensional data into one-dimensional data, and translates the
corresponding coordinates from multi-dimensions into one-dimension so that the
resultant one-dimensional data can be divided and allocated equally to the
processes. As a result, differently from previous works that have the
dimensions of decomposition pre-defined, our method can adaptively decompose
the FFT data on the lowest possible dimensions depending on the number of
processes. In addition, this row-wise decomposition provides plenty of
alternatives in data transpose, and different transpose order results in
different amount of communication. We identify the best transpose orders with
smallest communication amounts for the 3-D, 4-D, and 5-D FFTs by analyzing all
possible cases. Given both communication efficiency and scalability, our method
is promising in development of highly efficient parallel packages for the FFT.


title: Hadronic Reaction Zones in Relativistic Nucleus-Nucleus Collisions

abstract:
  On the basis of the proposed algorithm for calculation of the hadron reaction
rates, the space-time structure of the relativistic nucleus-nucleus collisions
is studied. The reaction zones and the reaction frequencies for various types
of reactions are calculated for AGS and SPS energies within the microscopic
transport model. The relation of the reaction zones to the kinetic and chemical
freeze-out processes is discussed. It is shown that the space-time freeze-out
layer is most extended in time in the central region, while, especially for
higher collision energies, the layer becomes very narrow at the sides. The
parametrization of freeze-out hypersurface in the form of specific hyperbola of
constant proper time was confirmed. The specific characteristic time moments of
the fireball evolution are introduced. It is found that the time of the
division of a reaction zone into two separate parts does not depend on the
collision energy. Calculations of the hadronic reaction frequency show that the
evolution of nucleus-nucleus collision can be divided into two hadronic stages.


title:
Dual Lower Bounds for Approximate Degree and Markov-Bernstein
  Inequalities

abstract:
  The $\epsilon$-approximate degree of a Boolean function $f: \{-1, 1\}^n \to
\{-1, 1\}$ is the minimum degree of a real polynomial that approximates $f$ to
within $\epsilon$ in the $\ell_\infty$ norm. We prove several lower bounds on
this important complexity measure by explicitly constructing solutions to the
dual of an appropriate linear program. Our first result resolves the
$\epsilon$-approximate degree of the two-level AND-OR tree for any constant
$\epsilon > 0$. We show that this quantity is $\Theta(\sqrt{n})$, closing a
line of incrementally larger lower bounds. The same lower bound was recently
obtained independently by Sherstov using related techniques. Our second result
gives an explicit dual polynomial that witnesses a tight lower bound for the
approximate degree of any symmetric Boolean function, addressing a question of
\v{S}palek. Our final contribution is to reprove several Markov-type
inequalities from approximation theory by constructing explicit dual solutions
to natural linear programs. These inequalities underly the proofs of many of
the best-known approximate degree lower bounds, and have important uses
throughout theoretical computer science.


title:
Stochastic Multiobjective Acceptability Analysis for the Choquet
  integral preference model and the scale construction problem

abstract:
  The Choquet integral is a preference model used in Multiple Criteria Decision
Aiding (MCDA) to deal with interactions between criteria. The Stochastic
Multiobjective Acceptability Analysis (SMAA) is an MCDA methodology used to
take into account imprecision or lack of data in the problem at hand. For
example, SMAA permits to compute the frequency that an alternative takes the
k-th rank in the whole space of the admissible preference parameters, e.g. in
case evaluations on the considered criteria are aggregated through the weighted
sum model, in the space of weights compatible with the preference information
supplied by the Decision Maker (DM). In this paper, we propose to integrate the
SMAA methodology with the Choquet integral preference model in order to get
robust recommendations taking into account the whole space of preference
parameters compatible with the DM's preference information. In case the
alternatives are evaluated by all the criteria on a common scale, the
preference parameters are given by the capacity expressing the non-additive
weights, representing the importance of criteria and their interaction. If the
criteria are instead evaluated on different scales, besides the capacity,
preference parameters include the common scale on which the evaluations of
criteria have to be recoded to be compared. Our approach permits to explore the
whole space of preference parameters being capacities and common scales
compatible with the DM's preference information.


title: The Broken Ray Transform On The Square

abstract:
  We study a particular broken ray transform on the Euclidean unit square and
establish injectivity and stability for $C_{0}^{2}$ perturbations of the
constant unit weight. Given an open subset $E$ of the boundary, we measure the
attenuation of all broken rays starting and ending at $E$ with the standard
optical reflection rule. Using the analytic microlocal approach of Frigyik,
Stefanov, and Uhlmann for the X-ray transform on generic families of curves, we
show injectivity via a path unfolding argument under suitable conditions on the
available broken rays. Then we show that with a suitable decomposition of the
measurement operator via smooth cutoff functions, the associated normal
operator is a classical pseudo differential operator of order -1 plus a
smoothing term with $C_{0}^{\infty}$ Schwartz kernel, which leads to the
desired result.


title: Phoneme discrimination using $KS$-algebra II

abstract:
  $KS$-algebra consists of expressions constructed with four kinds operations,
the minimum, maximum, difference and additively homogeneous generalized means.
Five families of $Z$-classifiers are investigated on binary classification
tasks between English phonemes. It is shown that the classifiers are able to
reflect well known formant characteristics of vowels, while having very small
Kolmogoroff's complexity.


title:
From Complex to Stochastic Potential: Heavy Quarkonia in the Quark-Gluon
  Plasma

abstract:
  The in-medium physics of heavy quarkonium is an ideal proving ground for our
ability to connect knowledge about the fundamental laws of physics to
phenomenological predictions. One possible route to take is to attempt a
description of heavy quark bound states at finite temperature through a
Schroedinger equation with an instantaneous potential. Here we review recent
progress in devising a comprehensive approach to define such a potential from
first principles QCD and extract its, in general complex, values from
non-perturbative lattice QCD simulations. Based on the theory of open quantum
systems we will show how to interpret the role of the imaginary part in terms
of spatial decoherence by introducing the concept of a stochastic potential.
Shortcomings as well as possible paths for improvement are discussed.


title:
Plancherel-Rotach asymptotic expansion for some polynomials from
  indeterminate moment problems

abstract:
  We study the Plancherel--Rotach asymptotics of four families of orthogonal
polynomials, the Chen--Ismail polynomials, the Berg-Letessier-Valent
polynomials, the Conrad--Flajolet polynomials I and II. All these polynomials
arise in indeterminate moment problems and three of them are birth and death
process polynomials with cubic or quartic rates. We employ a difference
equation asymptotic technique due to Z. Wang and R. Wong. Our analysis leads to
a conjecture about large degree behavior of polynomials orthogonal with respect
to solutions of indeterminate moment problems.


title: Prey switching with a linear preference trade-off

abstract:
  In ecology, prey switching refers to a predator's adaptive change of habitat
or diet in response to prey abundance. In this paper, we study piecewise-smooth
models of predator-prey interactions with a linear trade-off in a predator's
prey preference. We consider optimally foraging predators and derive a model
for a 1 predator-2 prey interaction with a tilted switching manifold between
the two sides of discontinuous vector fields. We show that the 1 predator-2
prey system undergoes a novel adding-sliding-like (center to two-part periodic
orbit; "C2PO") bifurcation in which the prey ratio transitions from constant to
time-dependent. Further away from the bifurcation point, the period of the
oscillating prey ratio period doubles, suggesting a possible cascade to chaos.
We compare our model predictions with data and demonstrate that we successfully
capture the periodicity in the ratio between the predator's preferred and
alternative prey types in data on freshwater plankton. Our study suggests that
it is useful to investigate prey ratio as a possible indicator of how
population dynamics can be influenced by ecosystem diversity.


title: Anisotropic universes in the ghost-free bigravity

abstract:
  We study Bianchi cosmologies in the ghost-free bigravity theory assuming both
metrics to be homogeneous and anisotropic, of the Bianchi class A, which
includes types I,II,VI$_0$,VII$_0$,VIII, and IX. We assume the universe to
contain a radiation and a non-relativistic matter, with the cosmological term
mimicked by the graviton mass. We find that, for generic initial values leading
to a late-time self-acceleration, the universe approaches a state with
non-vanishing anisotropies. The anisotropy contribution to the total energy
density decreases much slower than in General Relativity and shows the same
falloff rate as the energy of a non-relativistic matter. The solutions show a
singularity in the past, and in the Bianchi IX case the singularity is
approached via a sequence of Kasner-like steps, which is characteristic for a
chaotic behavior.


title:
Real-Time Correlation Functions in the O(N) Model from the Functional
  Renormalization Group

abstract:
  In the framework of the functional renormalization group (FRG) we present a
simple truncation scheme for the computation of real-time mesonic n-point
functions, consistent with the derivative expansion of the effective action.
Via analytic continuation on the level of the flow equations we perform
calculations of mesonic spectral functions in the scalar O(N) model, which we
use as an exploratory example. By investigating the renormalization-scale
dependence of the 2-point functions we shed light on the nature of the sigma
meson, whose spectral properties are predominantly of dynamical origin.


title:
The $t$-analogs of string functions for $A_1^{(1)}$ and Hecke indefinite
  modular forms

abstract:
  We study generating functions for Lusztig's $t$-analog of weight
multiplicities associated to integrable highest weight representations of the
simplest affine Lie algebra $A_1^{(1)}$. At $t=1$, these reduce to the {\em
string functions} of $A_1^{(1)}$, which were shown by Kac and Peterson to be
related to certain Hecke indefinite modular forms. Using their methods, we
obtain a description of the general $t$-string function; we show that its
values can be realized as radial averages of a certain extension of the Hecke
indefinite modular form.


title:
Varied Perturbation Theory for the Dispersion Dip in the Two-Dimensional
  Heisenberg Quantum Antiferromagnet

abstract:
  We study the roton-like dip in the magnon dispersion at the boundary of the
Brillouin zone in the isotropic S=1/2 Heisenberg quantum antiferromagnet. This
high-energy feature is sometimes seen as indication of a fractionalization of
the magnons to spinons. In this article, we provide evidence that the
description of the dip in terms of magnons can be improved significantly by
applying more advanced evaluation schemes. In particular, we illustrate the
usefulness of the application of the principle of minimal sensitivity in varied
perturbation theory. Thereby, we provide an example for the application of this
approach to an extended condensed matter problem governed by correlations which
can trigger analogous investigations for many other systems.


title: Quantum toroidal and shuffle algebras

abstract:
  In this paper, we prove that the quantum toroidal algebra of gl_n is
isomorphic to the double shuffle algebra of Feigin and Odesskii for the cyclic
quiver. The shuffle algebra viewpoint will allow us to prove a factorization
formula for the universal R-matrix of the quantum toroidal algebra.


title: Ultra-Luminous X-Ray Sources in the Most Metal Poor Galaxies

abstract:
  Ultra-Luminous X-ray sources (ULX) are X-ray binaries with Lx>1E^39 ergs/s.
The most spectacular examples of ULX occur in starburst galaxies and are now
understood to be young, luminous High Mass X-ray Binaries. The conditions under
which ULX form are poorly understood, but recent evidence suggests they may be
more common in low metallicity systems. Here we investigate the hypothesis that
ULX form preferentially in low metallicity galaxies by searching for ULX in a
sample of Extremely Metal Poor Galaxies (XMPG) observed with the Chandra X-ray
Observatory. XMPG are defined as galaxies with log(O/H)+12<7.65, or less than
5% solar. These are the most metal-deficient galaxies known, and a logical
place to find ULX if they favor metal poor systems. We compare the number of
ULX (corrected for background contamination) per unit of star formation (Nulx)
in the XMPG sample with Nulx in a comparison sample of galaxies with higher
metallicities taken from the Spitzer Infrared Galaxy Sample (SINGS). We find
that ULX occur preferentially in the metal poor sample with a formal
statistical significance of 2.3 sigma. We do not see strong evidence for a
trend in the formation of ULX in the high metallicity sample: above 12+log(O/H)
~ 8.0 the efficiency of ULX production appears to be flat. The effect we see is
strongest in the lowest metallicity bin. We discuss briefly the implications of
these results for the formation of black holes in low metallicity gas.


title:
Ideal regularization of the Coulomb singularity in exact exchange by
  Wigner-Seitz truncated interactions: towards chemical accuracy in non-trivial
  systems

abstract:
  Hybrid density functionals show great promise for chemically-accurate first
principles calculations, but their high computational cost limits their
application in non-trivial studies, such as exploration of reaction pathways of
adsorbents on periodic surfaces. One factor responsible for their increased
cost is the dense Brillouin-zone sampling necessary to accurately resolve an
integrable singularity in the exact exchange energy. We analyze this
singularity within an intuitive formalism based on Wannier-function
localization and analytically prove Wigner-Seitz truncation to be the ideal
method for regularizing the Coulomb potential in the exchange kernel. We show
that this method is limited only by Brillouin-zone discretization errors in the
Kohn-Sham orbitals, and hence converges the exchange energy exponentially with
the number of k-points used to sample the Brillouin zone for all but
zero-temperature metallic systems. To facilitate the implementation of this
method, we develop a general construction for the plane-wave Coulomb kernel
truncated on the Wigner-Seitz cell in one, two or three lattice directions. We
compare several regularization methods for the exchange kernel in a variety of
real systems including low-symmetry crystals and low-dimensional materials. We
find that our Wigner-Seitz truncation systematically yields the best k-point
convergence for the exchange energy of all these systems and delivers an
accuracy to hybrid functionals comparable to semi-local and screened-exchange
functionals at identical k-point sets.


title:
Particle model for skyrmions in metallic chiral magnets: dynamics,
  pinning and creep

abstract:
  Recently spin textures called skyrmions have been discovered in certain
chiral magnetic materials without spatial inversion symmetry, and have
attracted enormous attention due to their promising application in spintronics
since only a low applied current is necessary to drive their motion. When a
conduction electron moves around the skyrmion, its spin is fully polarized by
the spin texture and acquires a quantized phase; thus, the skyrmion yields an
emergent electrodynamics that in turn determines skyrmion motion and gives rise
to a finite Hall angle. While Skyrmions behave as particles, no particle level
description of their dynamics exists to date. Such a model would have
tremendous impact on understanding skyrmion dynamics by theoretical analysis
and computational modeling. Here we derive the equation of motion from a
microscopic continuum model and obtain the short-range interaction between
skyrmions, and the interaction between skyrmions and defects. Skyrmions also
experience a Magnus force perpendicular to their velocity due to the underlying
emergent electromagnetic field. We validate the equation of motion by studying
the depinning transition using both the particle and the continuum models. By
using the particle description, we explain the recent experimental observations
of the rotation of a skyrmion lattice in the presence of a temperature
gradient. We also predict quantum and thermal creep motion of skyrmions in the
pinning potential.


title:
Analysis of shot noise in the detection of ultrashort optical pulse
  trains

abstract:
  We present a frequency domain model of shot noise in the photodetection of
ultrashort optical pulse trains using a time-varying analysis. Shot
noise-limited photocurrent power spectral densities, signal-to-noise
expressions, and shot noise spectral correlations are derived that explicitly
include the finite response of the photodetector. It is shown that the strength
of the spectral correlations in the shot noise depends on the optical pulse
width, and that these correlations can create orders-of-magnitude imbalance
between the shot noise-limited amplitude and phase noise of photonically
generated microwave carriers. It is also shown that only by accounting for
spectral correlations can shot noise be equated with the fundamental quantum
limit in the detection of optical pulse-to-pulse timing jitter.


title:
Killing-Yano tensors in spaces admitting a hypersurface orthogonal
  Killing vector

abstract:
  Methods are presented for finding Killing-Yano tensors, conformal
Killing-Yano tensors, and conformal Killing vectors in spacetimes with a
hypersurface orthogonal Killing vector. These methods are similar to a method
developed by the authors for finding Killing tensors. In all cases one
decomposes both the tensor and the equation it satisfies into pieces along the
Killing vector and pieces orthogonal to the Killing vector. Solving the
separate equations that result from this decomposition requires less computing
than integrating the original equation. In each case, examples are given to
illustrate the method.


title:
Microwave control of atomic motional states in a spin-dependent optical
  lattice

abstract:
  Spin-dependent optical potentials allow us to use microwave radiation to
manipulate the motional state of trapped neutral atoms (F\"orster et al. 2009
Phys. Rev. Lett. 103, 233001). Here, we discuss this method in greater detail,
comparing it to the widely-employed Raman sideband coupling method. We provide
a simplified model for sideband cooling in a spin-dependent potential, and we
discuss it in terms of the generalized Lamb-Dicke parameter. Using a master
equation formalism, we present a quantitative analysis of the cooling
performance for our experiment, which can be generalized to other experimental
settings. We additionally use microwave sideband transitions to engineer
motional Fock states and coherent states, and we devise a technique for
measuring the population distribution of the prepared states.


title: Noncommutative Complete Intersections

abstract:
  Several generalizations of a commutative ring that is a graded complete
intersection are proposed for a noncommutative graded $k$-algebra; these
notions are justified by examples from noncommutative invariant theory.


title:
A Homogeneous Ensemble of Artificial Neural Networks for Time Series
  Forecasting

abstract:
  Enhancing the robustness and accuracy of time series forecasting models is an
active area of research. Recently, Artificial Neural Networks (ANNs) have found
extensive applications in many practical forecasting problems. However, the
standard backpropagation ANN training algorithm has some critical issues, e.g.
it has a slow convergence rate and often converges to a local minimum, the
complex pattern of error surfaces, lack of proper training parameters selection
methods, etc. To overcome these drawbacks, various improved training methods
have been developed in literature; but, still none of them can be guaranteed as
the best for all problems. In this paper, we propose a novel weighted ensemble
scheme which intelligently combines multiple training algorithms to increase
the ANN forecast accuracies. The weight for each training algorithm is
determined from the performance of the corresponding ANN model on the
validation dataset. Experimental results on four important time series depicts
that our proposed technique reduces the mentioned shortcomings of individual
ANN training algorithms to a great extent. Also it achieves significantly
better forecast accuracies than two other popular statistical models.


title:
The Connection between Star Formation and Metallicity Evolution in
  Barred Spiral Galaxies

abstract:
  We have performed a series of chemodynamical simulations of barred disc
galaxies. Our goal is to determine the physical processes responsible for the
increase in the central gas-phase metallicity and of the central SFR observed
in SDSS. We define a 2kpc diameter central aperture to approximate the
integrated spectroscopic fibre measurements from the SDSS. The chemical
evolution observed within this central region depends critically upon the
relative size of the bar and the aperture, which evolves strongly with time. At
t~0.5Gyr, a strong bar forms, whose length is considerably longer than the 2kpc
aperture. The stars and gas lose angular momentum and follow elongated orbits
that cause an intense mixing of the gas between the central region and its
surroundings. During the next 1.5Gyr, the orbits of the gas contract
significantly until the entire gas bar is contained in the 2kpc aperture,
resulting in a net flux of gas into the central region. During this period, the
metallicity in the central region increases steadily, and this enrichment is
dominated by metal-rich gas that is flowing into the central region. The main
result of this work is therefore that the observed enrichment in the centres of
barred galaxies is not dominated by in-situ enrichment by stars formed in the
centre. Rather, star formation occurs along the full length of the bar, much of
which occurs initially outside the 2kpc aperture. About 50% of the metals that
end up in the central region originate from this extended bar-long star
formation, but flow into the central region due to loss of angular momentum. We
conclude that there is no direct connection between central SFR and central
metallicity. The central metallicity does not originate exclusively from
central stars. Instead, the global SFR (especially along the bar) and the
large-scale flow of enriched gas play a major role.


title: On The EU and Euro-zone Stability

abstract:
  The aim of the present article is to offer a strictly mathematical,
statistical treatment of the current account balances in EU and in the
Eurozone. Based on Eurostat data, an overview of the total and annual balances
is first made for different collections among the EU countries. Then, using the
Mathematica technical computing software, curve fitting is employed to
determine the functions which best reflect how surpluses and deficits
accumulate with time. It is shown that both EU and the Eurozone economies
ultimately have to pass through a critical, turning point beyond which the
accumulation of deficits exceeds the accumulation of surpluses thus marking a
period of instability. An interval estimate at a ninety eight percent degree of
confidence, yields that EU is found in a phase of instability since 2011 while
the instability turning point for the Eurozone is bound to occur any year from
2015 to 2018.


title: Comptonization in 1E 1740.7-2942 spectra from 2 to 200 keV

abstract:
  Studies of the long-term spectral variations have been used to constrain the
emission processes of black hole candidates. However, a common scenario which
is able to explain the emission from soft to hard X-rays has been proposed only
recently. Here, we use XMM and INTEGRAL data on 1E 1740.7-2942 in order to
demonstrate that Comptonization plays an important role in producing high
energy photons, as predicted by the current modeling scenario.


title:
Modification of conceptual clustering algorithm Cobweb for numerical
  data using fuzzy membership function

abstract:
  Modification of a conceptual clustering algorithm Cobweb for the purpose of
its application for numerical data is offered. Keywords: clustering, algorithm
Cobweb, numerical data, fuzzy membership function.


title: Multiple polylogarithms and linearly reducible Feynman graphs

abstract:
  We review an approach for the computation of Feynman integrals by use of
multiple polylogarithms, with an emphasis on the related criterion of linear
reducibility of the graph. We show that the set of graphs which satisfies the
linear reducibility with respect to both Symanzik polynomials is closed under
taking minors. As a step towards a classification of Feynman integrals, we
discuss the concept of critical minors and exhibit an example at three loops
with four on-shell legs.


title:
Higgs boson production in association with a jet at
  next-to-next-to-leading order in perturbative QCD

abstract:
  We report on a calculation of the cross-section for Higgs boson production in
gluon fusion in association with a hadronic jet at next-to-next-to-leading
order (NNLO) in perturbative QCD. The computational technique is discussed in
detail. We show explicitly how to employ known soft and collinear limits of
scattering amplitudes to construct subtraction terms for NNLO computations.
Cancellation of singularities is demonstrated numerically for the
collinearly-subtracted $gg \to H + j $ cross-section through NNLO and the
finite $\sigma_{gg \to Hj}$ cross-section is computed through ${\cal
O}(\alpha_s^5)$ as a function of the center-of-mass collision energy. We
present numerical results for the gluon-fusion contribution to Higgs production
in association with a jet at the LHC. The NNLO QCD corrections significantly
reduce the residual scale dependence of the cross-section. The computational
method that we describe in this paper is applicable to the calculation of NNLO
QCD corrections to any other $ 2 \to 2$ process at a hadron collider


title: The AdS/CFT relation, quasi-normal modes and applications

abstract:
  Here we present a fast review of some of developments and new results
concerning applications of gravity in the context of the AdS/CFT
correspondence, in brane world perturbations as well as in holographic
superconductors. We also discuss the structure of the phase transitions in a
more general set up defined by the quasi-normal oscillations in the bulk, which
signalize a very complex structure of the phase transition at the border.


title: Feshbach projection formalism for open quantum systems

abstract:
  We provide a new approach to open quantum systems which is based on the
Feshbach projection method in an appropriate Hilbert space. Instead of looking
for a master equation for the dynamical map acting in the space of density
operators we provide the corresponding equation for the evolution in the
Hilbert space of the system. Its solution enables one to construct a legitimate
quantum evolution (completely positive and trace preserving). The big advantage
of this approach is the ability of performing a consistent approximation which
creates notorious problems in the standard Nakajima-Zwanzig approach. The new
scheme is illustrated by well known spin-boson model beyond rotating wave
approximation.


title:
Deformations of gauged SO(8) supergravity and supergravity in eleven
  dimensions

abstract:
  Motivated by the fact that there exists a continuous one-parameter family of
gauged SO(8) supergravities, possible eleven-dimensional origins of this
phenomenon are explored. Taking the original proof of the consistency of the
truncation of 11D supergravity to SO(8) gauged supergravity as a starting
point, a number of critical issues is discussed, such as the preferred
electric-magnetic duality frame in four dimensions and the existence of dual
magnetic gauge fields and related quantities in eleven dimensions. Some of
those issues are resolved but others seem to point to obstructions in embedding
the continuous degeneracy in 11D supergravity. While the final outcome of these
efforts remains as yet inconclusive, several new results are obtained. Among
those is the full non-linear ansatz for the seven-dimensional flux expressed in
terms of the scalars and pseudoscalars of 4D supergravity, valid for both the
S^7 and the T^7 truncations without resorting to tensor-scalar duality.


title: Directed closure measures for networks with reciprocity

abstract:
  The study of triangles in graphs is a standard tool in network analysis,
leading to measures such as the \emph{transitivity}, i.e., the fraction of
paths of length $2$ that participate in triangles. Real-world networks are
often directed, and it can be difficult to "measure" this network structure
meaningfully. We propose a collection of \emph{directed closure values} for
measuring triangles in directed graphs in a way that is analogous to
transitivity in an undirected graph. Our study of these values reveals much
information about directed triadic closure. For instance, we immediately see
that reciprocal edges have a high propensity to participate in triangles. We
also observe striking similarities between the triadic closure patterns of
different web and social networks. We perform mathematical and empirical
analysis showing that directed configuration models that preserve reciprocity
cannot capture the triadic closure patterns of real networks.


title: DisPerSE: robust structure identification in 2D and 3D

abstract:
  We present the DIScrete PERsistent Structures Extractor (DisPerSE), an open
source software for the automatic and robust identification of structures in 2D
and 3D noisy data sets. The software is designed to identify all sorts of
topological structures, such as voids, peaks, sources, walls and filaments
through segmentation, with a special emphasis put on the later ones. Based on
discrete Morse theory, DisPerSE is able to deal directly with noisy datasets
using the concept of persistence (a measure of the robustness of topological
features) and can be applied indifferently to various sorts of data-sets
defined over a possibly bounded manifold : 2D and 3D images, structured and
unstructured grids, discrete point samples via the delaunay tesselation,
Healpix tesselations of the sphere, ...
  Although it was initially developed with cosmology in mind, various I/O
formats have been implemented and the current version is quite versatile. It
should therefore be useful for any application where a robust structure
identification is required as well as for studying the topology of sampled
functions (e.g. computing persistent Betti numbers).
  DisPerSE can be downloaded directly from the website
http://www2.iap.fr/users/sousbie/ and a thorough online documentation is also
available at the same address.

categories: astro-ph.CO astro-ph.IM math-ph math.MP physics.comp-ph physics.data-an


title: Entanglement Entropies in Conformal Systems with Boundaries

abstract:
  We study the entanglement entropies in one-dimensional open critical systems,
whose effective description is given by a conformal field theory with
boundaries. We show that for pure-state systems formed by the ground state or
by the excited states associated to primary fields, the entanglement entropies
have a finite-size behavior that depends on the correlation of the underlying
field theory. The analytical results are checked numerically, finding excellent
agreement for the quantum chains ruled by the theories with central charge
$c=1/2$ and $c=1$.


title: Bounding temporal quantum correlations

abstract:
  Sequential measurements on a single particle play an important role in
fundamental tests of quantum mechanics. We provide a general method to analyze
temporal quantum correlations, which allows us to compute the maximal
correlations for sequential measurements in quantum mechanics. As an
application, we present the full characterization of temporal correlations in
the simplest Leggett-Garg scenario and in the sequential measurement scenario
associated with the most fundamental proof of the Kochen-Specker theorem.


title: Distributed Computability in Byzantine Asynchronous Systems

abstract:
  In this work, we extend the topology-based approach for characterizing
computability in asynchronous crash-failure distributed systems to asynchronous
Byzantine systems. We give the first theorem with necessary and sufficient
conditions to solve arbitrary tasks in asynchronous Byzantine systems where an
adversary chooses faulty processes. In our adversarial formulation, outputs of
non-faulty processes are constrained in terms of inputs of non-faulty processes
only. For colorless tasks, an important subclass of distributed problems, the
general result reduces to an elegant model that effectively captures the
relation between the number of processes, the number of failures, as well as
the topological structure of the task's simplicial complexes.


title: Representation theory of the Yokonuma-Hecke algebra

abstract:
  We develop an inductive approach to the representation theory of the
Yokonuma-Hecke algebra ${\rm Y}_{d,n}(q)$, based on the study of the spectrum
of its Jucys-Murphy elements which are defined here. We give explicit formulas
for the irreducible representations of ${\rm Y}_{d,n}(q)$ in terms of standard
$d$-tableaux; we then use them to obtain a semisimplicity criterion. Finally,
we prove the existence of a canonical symmetrising form on ${\rm Y}_{d,n}(q)$
and calculate the Schur elements with respect to that form.


title: Angle-Resolved Spectroscopy of Parametric Fluorescence

abstract:
  The parametric fluorescence from a nonlinear crystal forms a conical
radiation pattern. We measure the angular and spectral distributions of
parametric fluorescence in a beta-barium borate crystal pumped by a 405-nm
diode laser employing angle-resolved imaging spectroscopy. The experimental
angle-resolved spectra and the generation efficiency of parametric down
conversion are compared with a plane-wave theoretical analysis. The parametric
fluorescence is used as a broadband light source for the calibration of the
instrument spectral response function in the wavelength range from 450 to 1000
nm.


title:
Monte Carlo investigation of a spherical ferrimagnetic core-shell
  nanoparticle under a time dependent magnetic field

abstract:
  Monte Carlo simulation based on Metropolis algorithm has been used with a
great success to analyze the dynamic phase transition properties of a single
spherical core-shell nanoparticle system with a spin-3/2 core surrounded by a
spin-1 shell layer with antiferromagnetic interface coupling under the
influence of a time dependent oscillating magnetic filed. It has been found
that the dynamic phase boundaries strongly depend on the Hamiltonian parameters
such as for the high amplitude and period values of the external field, the
phase transition temperature sharply changes whereas it tends to slowly alter
as the reduced magnitude of interlayer parameter $\mathrm{J_{int}/J_{sh}}$
increases. Moreover, it is observed that the magnetization curves of the
particle have been found to obey P-type, N-type and Q-type classification
schemes under certain conditions. Much effort has also been paid to the
influence of the particle size on the thermal and magnetic properties of the
particle. Finally, a comparison of our observations with those of recently
published study including dynamic treatments of a nanocubic core-shell system
is represented and the findings indicate that there exists a qualitatively good
agreement with some relatively distinct differences.


title: Self Regulated Shocks in Massive Star Binary Systems

abstract:
  In an early-type, massive star binary system, X-ray bright shocks result from
the powerful collision of stellar winds driven by radiation pressure on
spectral line transitions. We examine the influence of the X-rays from the
wind-wind collision shocks on the radiative driving of the stellar winds using
steady state models that include a parameterized line force with X-ray
ionization dependence. Our primary result is that X-ray radiation from the
shocks inhibits wind acceleration and can lead to a lower pre-shock velocity,
and a correspondingly lower shocked plasma temperature, yet the intrinsic X-ray
luminosity of the shocks, LX remains largely unaltered, with the exception of a
modest increase at small binary separations. Due to the feedback loop between
the ionizing X-rays from the shocks and the wind-driving, we term this scenario
as self regulated shocks. This effect is found to greatly increase the range of
binary separations at which a wind-photosphere collision is likely to occur in
systems where the momenta of the two winds are significantly different.
Furthermore, the excessive levels of X-ray ionization close to the shocks
completely suppresses the line force, and we suggest that this may render
radiative braking less effective. Comparisons of model results against
observations reveals reasonable agreement in terms of log(LX/Lbol). The
inclusion of self regulated shocks improves the match for kT values in roughly
equal wind momenta systems, but there is a systematic offset for systems with
unequal wind momenta (if considered to be a wind-photosphere collision).


title: TASI 2012: Super-Tricks for Superspace

abstract:
  These lectures from the TASI 2012 summer school outline the basics of
supersymmetry (SUSY) in 3+1 dimensions. Starting from a ground-up development
of superspace, we develop all of the tools necessary to construct SUSY
lagrangians. While aimed at an introductory level, these lectures incorporate a
number of "super-tricks" for SUSY aficionados, including SUSY-covariant
derivatives, equations of motion in superspace, background field methods, and
non-linear realizations of goldstinos.


title:
Infinite examples of cancellative monoids that do not always have least
  common multiple

abstract:
  We will study the presentations of fundamental groups of the complement of
complexified real affine line arrangements that do not contain two parallel
lines. By Yoshinaga's minimal presentation, we can give positive homogeneous
presentations of the fundamental groups. We consider the associated monoids
defined by the presentations. It turns out that, in some cases, left (resp.
right) \emph{least common multiple} does not always exist. Hence, the monoids
are neither \emph{Garside} nor \emph{Artin}. Nevertheless, we will show that
they carry certain particular elements similar to the \emph{fundamental
elements} in Artin monoids, and that, by improving the classical method in
combinatorial group theory, they are \emph{cancellative monoids}. As a result,
we will show that the word problem can be solved and the center of them are
determined.


title:
Using High-Resolution Optical Spectra to Measure Intrinsic Properties of
  Low-Mass Stars: New Properties for KOI-314 and GJ 3470

abstract:
  We construct high signal-to-noise "template" spectra by co-adding hundreds of
spectra of nearby dwarfs spanning K7 to M4, taken with Keck/HIRES as part of
the California Planet Search. We identify several spectral regions in the
visible (370 - 800 nm) that are sensitive to the stellar luminosity and
metallicity. We use these regions to develop a spectral calibration method to
measure the mass, metallicity, and distance of low-mass stars, without the
requirement of geometric parallaxes. Testing our method on a sample of nearby M
dwarfs we show that we can reproduce stellar masses to about 8 - 10%,
metallicity to ~0.15 dex and distance to 11%. We were able to make use of HIRES
spectra obtained as part of the radial velocity monitoring of the star KOI-314
to derive a new mass estimate of 0.57 +/- 0.05 Msun, a radius of 0.54 +/- 0.05
Rsun, a metallicity, [Fe/H], of -0.28 +/- 0.10 and a distance of 66.5 +/- 7.3
pc. Using HARPS archival data and combining our spectral method with
constraints from transit observations, we are also able to derive the stellar
properties of GJ3470, a transiting planet hosting M dwarf. We estimate a mass
of 0.53 +/- 0.05 Msun, a radius of 0.50 +/- 0.05 Rsun, a metallicity, [Fe/H] =
0.12 +/- 0.12 and a distance of 29.9_{-3.4}^{+3.7} pc.


title:
Systematics in Metallicity Gradient Measurements I : Angular Resolution,
  Signal-to-Noise and Annuli Binning

abstract:
  With the rapid progress in metallicity gradient studies at high-redshift, it
is imperative that we thoroughly understand the systematics in these
measurements. This work investigates how the [NII]/Halpha ratio based
metallicity gradients change with angular resolution, signal-to-noise (S/N),
and annular binning parameters. Two approaches are used: 1. We downgrade the
high angular resolution integral-field data of a gravitationally lensed galaxy
and re-derive the metallicity gradients at different angular resolution; 2. We
simulate high-redshift integral field spectroscopy (IFS) observations under
different angular resolution and S/N conditions using a local galaxy with a
known gradient. We find that the measured metallicity gradient changes
systematically with angular resolution and annular binning. Seeing-limited
observations produce significantly flatter gradients than higher angular
resolution observations. There is a critical angular resolution limit beyond
which the measured metallicity gradient is substantially different to the
intrinsic gradient. This critical angular resolution depends on the intrinsic
gradient of the galaxy and is < 0.02 arcsec for our simulated galaxy. We show
that seeing-limited high-redshift metallicity gradients are likely to be
strongly affected by resolution-driven gradient flattening. Annular binning
with a small number of annuli produces a more flattened gradient than the
intrinsic gradient due to weak line smearing. For 3-annuli bins, a minimum S/N
of ~ 5 on the [NII] line is required for the faintest annulus to constrain the
gradients with meaningful errors.


title:
Herschel/HIFI search for H2-17O and H2-18O in IRC+10216: constraints on
  models for the origin of water vapor

abstract:
  We report the results of a sensitive search for the minor isotopologues of
water, H2-17O and H2-18O, toward the carbon-rich AGB star IRC+10216 (a.k.a. CW
Leonis) using the HIFI instrument on the Herschel Space Observatory. This
search was motivated by the fact that any detection of isotopic enhancement in
the H2-17O and H2-18O abundances would have strongly implicated CO
photodissociation as the source of the atomic oxygen needed to produce water in
a carbon-rich circumstellar envelope. Our observations place an upper limit of
1/470 on the H2-17O/H2-16O abundance ratio. Given the isotopic 17O/16O ratio of
1/840 inferred previously for the photosphere of IRC+10216, this result places
an upper limit of a factor 1.8 on the extent of any isotope-selective
enhancement of H2-17O in the circumstellar material, and provides an important
constraint on any model that invokes CO photodissociation as the source of O
for H2O production. In the context of the clumpy photodissociation model
proposed previously for the origin of water in IRC+10216, our limit implies
that 12C-16O (not 13C-16O or SiO) must be the dominant source of 16O for H2O
production, and that the effects of self-shielding can only have reduced the
12C-16O photodissociation rate by at most a factor ~ 2.


title:
Boson topological insulators: A window into highly entangled quantum
  phases

abstract:
  We study several aspects of the realization of global symmetries in highly
entangled phases of quantum matter. Examples include gapped topological ordered
phases, gapless quantum spin liquids and non-fermi liquid phases. An insightful
window into such phases is provided by recent developments in the theory of
short ranged entangled Symmetry Protected Topological (SPT) phases . First they
generate useful no-go constraints on how global symmetry may be implemented in
a highly entangled phase. Possible symmetry implementation in gapped
topological phases and some proposed gapless spin/bose liquids are examined in
this light. We show that some previously proposed spin liquid states for 2d
quantum magnets do not in fact have consistent symmetry implementation unless
they occur as the surface of a 3d SPT phase. A second SPT-based insight into
highly entangled states is the development of a view point of such states as
SPT phases of one of the emergent excitations. We describe this in the specific
context of time reversal symmetric 3d U(1) quantum spin liquids with an
emergent photon. Different such spin liquids are shown to be equivalent to
different SPT insulating phases of the emergent monopole excitation of such
phases. The highly entangled states also in turn enrich our understanding of
SPT phases. We use the insights obtained from our results to provide an
explicit construction of bosonic SPT phases in 3d in a system of coupled
layers. This includes construction of a time reversal symmetric SPT state that
is not currently part of the cohomology classification of such states.


title:
Conditions For Successful Helium Detonations In Astrophysical
  Environments

abstract:
  Several models for type Ia-like supernovae events rely on the production of a
self-sustained detonation powered by nuclear reactions. In the absence of
hydrogen, the fuel that powers these detonations typically consists of either
pure helium (He) or a mixture of carbon and oxygen (C/O). Studies that
systematically determine the conditions required to initiate detonations in C/O
material exist, but until now no analogous investigation of He matter has been
conducted. We perform one-dimensional reactive hydrodynamical simulations at a
variety of initial density and temperature combinations and find critical
length scales for the initiation of He detonations that range between 1 -
$10^{10}$ cm. A simple estimate of the length scales over which the total
consumption of fuel will occur for steady-state detonations is provided by the
Chapman-Jouguet (CJ) formalism. Our initiation lengths are consistently smaller
than the corresponding CJ length scales by a factor of $\Sim 100$, providing
opportunities for thermonuclear explosions in a wider range of low-mass white
dwarfs (WDs) than previously thought possible. We find that virialized WDs with
as little mass as 0.24 $M_\odot$ can be detonated, and that even less massive
WDs can be detonated if a sizable fraction of their mass is raised to a higher
adiabat. That the initiation length is exceeded by the CJ length implies that
certain systems may not reach nuclear statistical equilibrium within the time
it takes a detonation to traverse the object. In support of this hypothesis, we
demonstrate that incomplete burning will occur in the majority of He WD
detonations and that $^{40}$Ca, $^{44}$Ti, or $^{48}$Cr, rather than $^{56}$Ni,
is the predominant burning product for many of these events. We anticipate that
...


title:
A redline starburst: CO(2-1) observations of an Eddington-limited galaxy
  reveal star formation at its most extreme

abstract:
  We report observations of the CO(2-1) emission of SDSSJ1506+54, a compact
(r_e~135pc) starburst galaxy at z=0.6. SDSSJ1506+54 appears to be forming stars
close to the limit allowed by stellar radiation pressure feedback models: the
measured L_IR/L'_CO 1500 is one of the highest measured for any galaxy. With
its compact optical morphology but extended low surface brightness envelope,
post-starburst spectral features, high infrared luminosity (L_IR>10^12.5
L_Sun), low gas fraction (M_H2/M_stars~15%), and short gas depletion time (tens
of Myr), we speculate that this is a feedback- limited central starburst
episode at the conclusion of a major merger. Taken as such, SDSSJ1504+54
epitomizes the brief closing stage of a classic model of galaxy growth: we are
witnessing a key component of spheroid formation during what we term a
'redline' starburst.


title: The strong environmental dependence of black hole scaling relations

abstract:
  We investigate how the scaling relations between central black hole mass
(Mbh) and host galaxy properties (velocity dispersion, bulge stellar mass and
bulge luminosity) depend on the large scale environment. For each of a sample
of 69 galaxies with dynamical black hole measurements we compile four
environmental measures (nearest neighbor distance, fixed aperture number
density, total halo mass, and central/satellite). We find that central and
satellite galaxies follow distinctly separate scalings in each of the three
relations we have examined. The Mbh - sigma relation of central galaxies is
significantly steeper (6.38 +/- 0.49) than that of satellite galaxies (4.91 +/-
0.49), but has a similar intercept. This behavior remains even after
restricting to a sample of only early type galaxies or after removing the 8
brightest cluster galaxies. The Mbh - sigma relation shows more modest
differences when splitting the sample based on the other environmental
indicators, suggesting that they are driven by the underlying satellite/central
fractions. Separate relations for centrals and satellites are also seen in the
power law scaling between black hole mass and bulge stellar mass or bulge
luminosity. We suggest that gas rich, low mass galaxies undergo a period of
rapid black hole growth in the process of becoming satellites. If central
galaxies on the current Mbh - sigma relation are representative progenitors of
the satellite population, the observations imply that a sigma = 120 km/s galaxy
must nearly triple its central black hole mass. The elevated black hole masses
of massive central galaxies are then a natural consequence of the accretion of
satellites.


title: Buckets of Tops

abstract:
  Reconstructing hadronically decaying top quarks is a key challenge at the
LHC, affecting a long list of Higgs analyses and new physics searches. We
propose a new method of collecting jets in buckets, corresponding to top quarks
and initial state radiation. This method is particularly well suited for
moderate transverse momenta of the top quark, closing the gap between top
taggers and traditional top reconstruction. Applying it to searches for
supersymmetric top squarks we illustrate the power of buckets.


title:
Widefield VLBI observations of M31: A Unique Probe of the Ionized ISM of
  a nearby galaxy

abstract:
  The VLBA was used at 1.6 GHz to observe a target field 50 arcminutes in
diameter including the core of M31. Novel VLBI correlation techniques were used
to observe 200 sources simultaneously, of which 16 were detected. We classify
all 16 as background AGN based on their X-ray properties and arcsecond- and
mas-scale morphology. The detected sources were then analyzed for evidence of
scatter-broadening due to the ionized ISM of M31. The detection of a compact
background source only 0.25 kpc projected distance from M31 places a constraint
on the extent of any extreme scattering region associated with center of M31.
However, the two sources closest to the core show evidence of scatter
broadening consistent with that which would be observed if a compact source
were observed through the inner disk of our Galaxy at the inclination of M31.
We interpret this as a detection of the ionized ISM of M31 along two lines of
sight. With the increases in bandwidth and sensitivity envisaged for future
long-baseline interferometers, this should prove to be a remarkably powerful
technique for understanding the ionized ISM in external galaxies.


title:
On The Robustness of z=0-1 Galaxy Size Measurements Through Model and
  Non-Parametric Fits

abstract:
  We present the size-stellar mass relations of nearby (z=0.01-0.02) Sloan
Digital Sky Survey galaxies, for samples selected by color, morphology, Sersic
index n, and specific star formation rate. Several commonly employed size
measurement techniques are used, including single Sersic fits, two-component
Sersic models, and a non-parametric method. Through simple simulations, we show
that the non-parametric and two-component Sersic methods provide the most
robust effective radius measurements, while those based on single Sersic
profiles are often overestimates, especially for massive red/early-type
galaxies. Using our robust sizes, we show for all sub-samples that the
mass-size relations are shallow at low stellar masses and steepen above ~ 3-4 x
10^{10}\msun. The mass-size relations for galaxies classified as late-type,
low-n, and star-forming are consistent with each other, while blue galaxies
follow a somewhat steeper relation. The mass-size relations of early-type,
high-n, red, and quiescent galaxies all agree with each other but are somewhat
steeper at the high-mass end than previous results. To test potential
systematics at high redshift, we artificially redshifted our sample (including
surface brightness dimming and degraded resolution) to z=1 and re-fit the
galaxies using single Serisc profiles. The sizes of these galaxies before and
after redshifting are consistent and we conclude that systematic effects in
sizes and the size-mass relation at z ~ 1 are negligible. Interestingly, since
the poorer physical resolution at high redshift washes out bright galaxy
substructures, single-Sersic fitting appears to provide more reliable and
unbiased effective radius measurements at high z than for nearby, well-resolved
galaxies.


title: The parameter space in Galileon gravity models

abstract:
  We present the first constraints on the full parameter space of the Galileon
modified gravity model, considering both the cosmological parameters and the
coefficients which specify the additional terms in the Lagrangian due to the
Galileon field, which we call the Galileon parameters. We use the latest cosmic
microwave background measurements, along with distance measurements from
supernovae and baryonic acoustic oscillations, performing a Monte Carlo Markov
Chain exploration of the 9-dimensional parameter space. The integrated
Sachs-Wolfe signal can be very different in Galileon models compared to
standard gravity, making it essential to use the full CMB data rather than the
CMB distance priors. We demonstrate that meaningful constraints are only
possible in the Galileon parameter space after taking advantage of a scaling
degeneracy. We find that the Galileon model can fit the WMAP 9-year results
better than the standard \Lambda-Cold Dark Matter model, but gives a slightly
worse fit overall once lower redshift distance measurements are included. The
best-fitting cosmological parameters (e.g. matter density, scalar spectral
index, fluctuation amplitude) can differ by more than 2\sigma\ in the Galileon
model compared with \Lambda CDM. We highlight other potential constraints of
the Galileon model using galaxy clustering and weak lensing measurements.


title:
Detection of molecular absorption in the dayside of exoplanet 51 Pegasi
  b?

abstract:
  In this paper we present ground-based high-resolution spectroscopy of 51
Pegasi using CRIRES at the Very Large Telescope. The system was observed for
3x5 hours at 2.3 {\mu}m at a spectral resolution of R = 100,000, targeting
potential signatures from carbon monoxide, water vapour and methane in the
planet's dayside spectrum. In the first 2x5 hours of data, we find a combined
signal from carbon monoxide and water in absorption at a formal 5.9{\sigma}
confidence level, indicating a non-inverted atmosphere. We derive a planet mass
of M_P = (0.46 +- 0.02) M_Jup and an orbital inclination i between 79.6 and
82.2 degrees, with the upper limit set by the non-detection of the planet
transit in previous photometric monitoring. However, there is no trace of the
signal in the final 5 hours of data. A statistical analysis indicates that the
signal from the first two nights is robust, but we find no compelling
explanation for its absence in the final night. The latter suffers from
stronger noise residuals and greater instrumental instability than the first
two nights, but these cannot fully account for the missing signal. It is
possible that the integrated dayside emission from 51 Peg b is instead strongly
affected by weather. However, more data are required before we can claim any
time variability in the planet's atmosphere.


title: Tight Bounds for Rumor Spreading with Vertex Expansion

abstract:
  We establish a bound for the classic PUSH-PULL rumor spreading protocol on
arbitrary graphs, in terms of the vertex expansion of the graph. We show that
O(log^2(n)/\alpha) rounds suffice with high probability to spread a rumor from
a single node to all n nodes, in any graph with vertex expansion at least
\alpha. This bound matches the known lower bound, and settles the question on
the relationship between rumor spreading and vertex expansion asked by
Chierichetti, Lattanzi, and Panconesi (SODA 2010). Further, some of the
arguments used in the proof may be of independent interest, as they give new
insights, for example, on how to choose a small set of nodes in which to plant
the rumor initially, to guarantee fast rumor spreading.


title:
Giant planets orbiting metal-rich stars show signatures of planet-planet
  interactions

abstract:
  Gas giants orbiting interior to the ice line are thought to have been
displaced from their formation locations by processes that remain debated. Here
we uncover several new metallicity trends, which together may indicate that two
competing mechanisms deliver close-in giant planets: gentle disk migration,
operating in environments with a range of metallicities, and violent
planet-planet gravitational interactions, primarily triggered in metal-rich
systems in which multiple giant planets can form. First, we show with 99.1%
confidence that giant planets with semi-major axes between 0.1 and 1 AU
orbiting metal-poor stars ([Fe/H]<0) are confined to lower eccentricities than
those orbiting metal-rich stars. Second, we show with 93.3% confidence that
eccentric proto-hot Jupiters undergoing tidal circularization primarily orbit
metal-rich stars. Finally, we show that only metal-rich stars host a pile-up of
hot Jupiters, helping account for the lack of such a pile-up in the overall
Kepler sample. Migration caused by stellar perturbers (e.g. stellar Kozai) is
unlikely to account for the trends. These trends further motivate follow-up
theoretical work addressing which hot Jupiter migration theories can also
produce the observed population of eccentric giant planets between 0.1 and 1
AU.


title: Quantum Computation of Prime Number Functions

abstract:
  We propose a quantum circuit that creates a pure state corresponding to the
quantum superposition of all prime numbers less than 2^n, where n is the number
of qubits of the register. This Prime state can be built using Grover's
algorithm, whose oracle is a quantum implementation of the classical
Miller-Rabin primality test. The Prime state is highly entangled, and its
entanglement measures encode number theoretical functions such as the
distribution of twin primes or the Chebyshev bias. This algorithm can be
further combined with the quantum Fourier transform to yield an estimate of the
prime counting function, more efficiently than any classical algorithm and with
an error below the bound that allows for the verification of the Riemann
hypothesis. We also propose a Twin Prime state to measure the number of twin
primes and another state to test the Goldbach conjecture. Arithmetic properties
of prime numbers are then, in principle, amenable to experimental verifications
on quantum systems.


title: The CT10 NNLO Global Analysis of QCD

abstract:
  We present next-to-next-to-leading order (NNLO) parton distribution functions
(PDFs) from the CTEQ-TEA group. The CT10NNLO PDF fit is based on essentially
the same global data sets used in the CT10 and CT10W NLO PDF analyses. After
exploring the goodness of the fits to the HERA combined data and the Tevatron
jet data, we present various predictions at NNLO accuracy for both existing and
forthcoming precision measurements from the CERN Large Hadron Collider. The
range of variations in the gluon distribution introduced by correlated
systematic effects in inclusive jet production is also examined.


title:
Simulations of particle acceleration beyond the classical synchrotron
  burnoff limit in magnetic reconnection: An explanation of the Crab flares

abstract:
  It is generally accepted that astrophysical sources cannot emit synchrotron
radiation above 160 MeV in their rest frame. This limit is given by the balance
between the accelerating electric force and the radiation reaction force acting
on the electrons. The discovery of synchrotron gamma-ray flares in the Crab
Nebula, well above this limit, challenges this classical picture of particle
acceleration. To overcome this limit, particles must accelerate in a region of
high electric field and low magnetic field. This is possible only with a
non-ideal magnetohydrodynamic process, like magnetic reconnection. We present
the first numerical evidence of particle acceleration beyond the synchrotron
burnoff limit, using a set of 2D particle-in-cell simulations of
ultra-relativistic pair plasma reconnection. We use a new code, Zeltron, that
includes self-consistently the radiation reaction force in the equation of
motion of the particles. We demonstrate that the most energetic particles move
back and forth across the reconnection layer, following relativistic Speiser
orbits. These particles then radiate >160 MeV synchrotron radiation rapidly,
within a fraction of a full gyration, after they exit the layer. Our analysis
shows that the high-energy synchrotron flux is highly variable in time because
of the strong anisotropy and inhomogeneity of the energetic particles. We
discover a robust positive correlation between the flux and the cut-off energy
of the emitted radiation, mimicking the effect of relativistic Doppler
amplification. A strong guide field quenches the emission of >160 MeV
synchrotron radiation. Our results are consistent with the observed properties
of the Crab flares, supporting the reconnection scenario.


title: Exotic topological order in fractal spin liquids

abstract:
  We present a large class of three-dimensional spin models that possess
topological order with stability against local perturbations, but are beyond
description of topological quantum field theory. Conventional topological spin
liquids, on a formal level, may be viewed as condensation of string-like
extended objects with discrete gauge symmetries, being at fixed points with
continuous scale symmetries. In contrast, ground states of fractal spin liquids
are condensation of highly-fluctuating fractal objects with certain algebraic
symmetries, corresponding to limit cycles under real-space renormalization
group transformations which naturally arise from discrete scale symmetries of
underlying fractal geometries. A particular class of three-dimensional models
proposed in this paper may potentially saturate quantum information storage
capacity for local spin systems.


title: Tradeoff between Smoother and Sooner "Little Rip"

abstract:
  There exists dark energy models that predict the occurrence of "little rip".
At the point of little rip the Hubble rate and its cosmic time derivative
approach infinity, which is quite similar to the big rip singularity except
that the former happens at infinite future while the latter at a finite cosmic
time; both events happen in the future and at high energies. In the case of the
big rip, a combination of ultra-violet and infra-red effects can smooth its
doomsday. We therefore wonder if the little rip can also be smoothed in a
similar way. We address the ultra-violet and infra-red effects in general
relativity through a brane-world model with a Gauss-Bonnet term in the bulk and
an induced gravity term on the brane. We find that the little rip is
transformed in this case into a sudden singularity, or a "big brake". Even
though the big brake is smoother than the little rip in that the Hubble rate is
finite at the event, the trade-off is that it takes place sooner, at a finite
cosmic time. In our estimate, the big brake would happen at roughly 1300Gyr.


title:
Solutions of massive gravity theories in constant scalar invariant
  geometries

abstract:
  We solve massive gravity field equations in the framework of locally
homogenous and vanishing scalar invariant (VSI) Lorentzian spacetimes, which in
three dimensions are the building blocks of constant scalar invariant (CSI)
spacetimes. At first, we provide an exhaustive list of all Lorentzian
three-dimensional homogeneous spaces and then we determine the Petrov type of
the relevant curvature tensors. Among these geometries we determine for which
values of their structure constants they are solutions of the field equations
of massive gravity theories with cosmological constant. The homogeneous
solutions founded are of all various Petrov types : I_C, I_R, II, III, D_t,
D_s, N, O; the VSI geometries which we found are of Petrov type III. The Petrov
types II and III are new explicit CSI spacetimes solutions of these types. We
also examine the conditions under which the obtained anti-de Sitter solutions
are free of tachyonic massive graviton modes.


title: Frustration, Entanglement, and Correlations in Quantum Many Body Systems

abstract:
  We derive an exact lower bound to a universal measure of frustration in
degenerate ground states of quantum many-body systems. The bound results in the
sum of two contributions: entanglement and classical correlations arising from
local measurements. We show that average frustration properties are completely
determined by the behavior of the maximally mixed ground state. We identify
sufficient conditions for a quantum spin system to saturate the bound, and for
models with twofold degeneracy we prove that average and local frustration
coincide.


title:
Extragalactic Globular Cluster Populations from High Resolution
  Integrated Light Spectra

abstract:
  We present a comparison of high-resolution, integrated-light, detailed
chemical abundances for Galactic and extragalactic globular clusters in both
massive galaxies and dwarf galaxies. We include measurements of Fe, Ca, Si, Na,
and Al for globular cluster samples in the Milky Way, M31, Large Magellanic
Cloud, and NGC 5128. These and other recent results from our group on M31 and
NGC 5128 are the first chemical abundances derived from discrete absorption
features in old stars beyond the Milky Way and its nearest neighbors. These
abundances can provide both galaxy enrichment histories and constraints on
globular cluster formation and evolution.


title:
The Cluster and Field Galaxy AGN Fraction at z = 1 to 1.5: Evidence for
  a Reversal of the Local Anticorrelation Between Environment and AGN Fraction

abstract:
  The fraction of cluster galaxies that host luminous AGN is an important probe
of AGN fueling processes, the cold ISM at the centers of galaxies, and how
tightly black holes and galaxies co-evolve. We present a new measurement of the
AGN fraction in a sample of 13 clusters of galaxies (M >= 10^{14} Msun) at
1<z<1.5 selected from the Spitzer/IRAC Shallow Cluster Survey, as well as the
field fraction in the immediate vicinity of these clusters, and combine these
data with measurements from the literature to quantify the relative evolution
of cluster and field AGN from the present to z~3. We estimate that the cluster
AGN fraction at 1<z<1.5 is f_A = 3.0^{+2.4}_{-1.4}% for AGN with a rest-frame,
hard X-ray luminosity greater than L_{X,H} >= 10^{44} erg/s. This fraction is
measured relative to all cluster galaxies more luminous than M*_{3.6}(z)+1,
where M*_{3.6}(z) is the absolute magnitude of the break in the galaxy
luminosity function at the cluster redshift in the IRAC 3.6um bandpass. The
cluster AGN fraction is 30 times greater than the 3sigma upper limit on the
value for AGN of similar luminosity at z~0.25, as well as more than an order of
magnitude greater than the AGN fraction at z~0.75. AGN with L_{X,H} >= 10^{43}
erg/s exhibit similarly pronounced evolution with redshift. In contrast with
the local universe, where the luminous AGN fraction is higher in the field than
in clusters, the X-ray and MIR-selected AGN fractions in the field and clusters
are consistent at 1<z<1.5. This is evidence that the cluster AGN population has
evolved more rapidly than the field population from z~1.5 to the present. This
environment-dependent AGN evolution mimics the more rapid evolution of
star-forming galaxies in clusters relative to the field.


title: Large deviations of Lyapunov exponents

abstract:
  Generic dynamical systems have `typical' Lyapunov exponents, measuring the
sensitivity to small perturbations of almost all trajectories. A generic system
has also trajectories with exceptional values of the exponents, corresponding
to unusually stable or chaotic situations. From a more mathematical point of
view, large deviations of Lyapunov exponents characterize phase-space
topological structures such as separatrices, homoclinic trajectories and
degenerate tori. Numerically sampling such large deviations using the Lyapunov
Weighted
  Dynamics allows one to pinpoint, for example, stable configurations in
celestial mechanics or collections of interacting chaotic `breathers' in
nonlinear media. Furthermore, we show that this numerical method allows one to
compute the topological pressure of extended dynamical systems, a central
quantity in the Thermodynamic of Trajectories of Ruelle.


title:
Observation of incipient charge nematicity in
  Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$

abstract:
  Using electronic Raman spectroscopy, we report direct measurements of charge
nematic fluctuations in the tetragonal phase of strain-free
Ba(Fe$_{1-x}$Co$_{x})_{2}$As$_{2}$ single crystals. The strong enhancement of
the Raman response at low temperatures unveils an underlying charge nematic
state that extends to superconducting compositions and which has hitherto
remained unnoticed. Comparison between the extracted charge nematic
susceptibility and the elastic modulus allows us to disentangle the charge
contribution to the nematic instability, and to show that charge nematic
fluctuations are weakly coupled to the lattice.


title:
Parallel Maximum Clique Algorithms with Applications to Network Analysis
  and Storage

abstract:
  We propose a fast, parallel maximum clique algorithm for large sparse graphs
that is designed to exploit characteristics of social and information networks.
The method exhibits a roughly linear runtime scaling over real-world networks
ranging from 1000 to 100 million nodes. In a test on a social network with 1.8
billion edges, the algorithm finds the largest clique in about 20 minutes. Our
method employs a branch and bound strategy with novel and aggressive pruning
techniques. For instance, we use the core number of a vertex in combination
with a good heuristic clique finder to efficiently remove the vast majority of
the search space. In addition, we parallelize the exploration of the search
tree. During the search, processes immediately communicate changes to upper and
lower bounds on the size of maximum clique, which occasionally results in a
super-linear speedup because vertices with large search spaces can be pruned by
other processes. We apply the algorithm to two problems: to compute temporal
strong components and to compress graphs.


title: The Effective Theory of Long Strings

abstract:
  We present the low-energy effective theory on long strings in quantum field
theory, including a streamlined review of previous literature on the subject.
Such long strings can appear in the form of solitonic strings, as in the 4d
Abelian Higgs model, or in the form of confining strings, as in Yang-Mills
theories. The bottom line is that upon expanding in powers of 1/L the energy
levels of long (closed) strings (where L is the length of the string), all the
terms up to (and including) order 1/L^5 are universal. We argue that for
excited strings in D>3 space-time dimensions there is a universal deviation at
order 1/L^5 from the naive formula that is usually used to fit lattice results.
For D=3 this naive formula is valid even at order 1/L^5. At order 1/L^7
non-universal terms generically appear in all cases. We explain the physical
origin of these results, and illuminate them in three different formulations of
the effective action of long strings (the relationships among which we partly
clarify). In addition, we corroborate these results by an explicit computation
of the effective action on long strings in confining theories which have a
gravitational dual. These predictions can be tested by precise simulations of
4d Yang-Mills theory on the lattice.


title:
Patterns of conductivity in excitable automata with updatable intervals
  of excitations

abstract:
  We define a cellular automaton where a resting cell excites if number of its
excited neighbours belong to some specified interval and boundaries of the
interval change depending on ratio of excited and refractory neighbours in the
cell's neighbourhood. We calculate excitability of a cell as a number of
possible neighbourhood configurations that excite the resting cell. We call
cells with maximal values of excitability conductive. In exhaustive search of
functions of excitation interval updates we select functions which lead to
formation of connected configurations of conductive cells. The functions
discovered are used to design conductive, wire-like, pathways in initially
non-conductive arrays of cells. We demonstrate that by positioning seeds of
growing conductive pathways it is possible to implement a wide range of routing
operations, including reflection of wires, stopping wires, formation of
conductive bridges and generation of new wires in the result of collision. The
findings presented may be applied in designing conductive circuits in excitable
non-linear media, reaction-diffusion chemical systems, neural tissue and
assembles of conductive polymers.


title:
A Treatise on Stability of Autonomous and Non-autonomous Systems: Theory
  and Illustrative Practical Applications

abstract:
  Stability is a very important property of any physical system. By a stable
system, we broadly mean that small disturbances either in the system inputs or
in the initial conditions do not lead to large changes in the overall behavior
of the system. To be of practical use, a system must have to be stable. The
theory of stability is a vast, rapidly growing subject with prolific and
innovative contributions from numerous researchers. As such, an introductory
book that covers the basic concepts and minute details about this theory is
essential. The primary aim of this book is to make the readers familiar with
the various terminologies and methods related to the stability analysis of
time-invariant (autonomous) and time-varying (non-autonomous) systems. A
special treatment is given to the celebrated Liapunov's direct method which is
so far the most widely used and perhaps the best method for determining the
stability nature of both autonomous as well as non-autonomous systems. After
discussing autonomous systems to a considerable extent, the book concentrates
on the non-autonomous systems. From stability point of view, these systems are
often quite difficult to manage. Also, unlike their autonomous counterparts,
the non-autonomous systems often behave in peculiar manners which can make the
analysts arrive at misleading conclusions. Due to these issues, this book
attempts to present a careful and systematic study about the stability
properties of non-autonomous systems.


title:
Manipulating the Nanoscale Optical Transmission with a
  Meta-Transmitarray

abstract:
  By applying the optical nanocircuit concepts to metasurfaces, we propose an
effective route to locally control light transmission over a deeply
subwavelength scale. This concept realizes the optical equivalent of a
transmitarray, whose use is demonstrated for light bending and focusing with
unprecedented efficiency over a subwavelength distance, with crucial benefits
for nano-optics applications. These findings may lead to large improvements in
the manipulation of optical transmission and processing of nanoscale optical
signals over conformal and Si-compatible substrates.


title: The Ekedahl-Oort type of Jacobians of Hermitian curves

abstract:
  The Ekedahl-Oort type is a combinatorial invariant of a principally polarized
abelian variety $A$ defined over an algebraically closed field of
characteristic $p > 0$. It characterizes the $p$-torsion group scheme of $A$ up
to isomorphism. Equivalently, it characterizes (the mod $p$ reduction of) the
Dieudonn\'e module of $A$ or the de Rham cohomology of $A$ as modules under the
Frobenius and Vershiebung operators.
  There are very few results about which Ekedahl-Oort types occur for Jacobians
of curves. In this paper, we consider the class of Hermitian curves, indexed by
a prime power $q=p^n$, which are supersingular curves well-known for their
exceptional arithmetic properties. We determine the Ekedahl-Oort types of the
Jacobians of all Hermitian curves. An interesting feature is that their
indecomposable factors are determined by the orbits of the
multiplication-by-two map on ${\mathbb Z}/(2^n+1)$, and thus do not depend on
$p$. This yields applications about the decomposition of the Jacobians of
Hermitian curves up to isomorphism.


title: The depolarising channel and Horns problem

abstract:
  We investigate the action of the depolarising (qubit) channel on permutation
invariant input states. More specifically, we raise the question on which
invariant subspaces the output of the depolarising channel, given such special
input, is supported. An answer is given for equidistributed states on
isotypical subspaces, also called symmetric Werner states. Horns problem and
two of the corresponding inequalities are invoked as a method of proof.


title: Low Energy Measurements of the Weak Mixing Angle

abstract:
  We review the status of precision measurements of weak neutral current
interactions, mediated by the $Z^0$ boson, at $Q^2\ll M_Z^2$. They can be used
to extract values for the weak mixing angle $\sin^2\theta_W$, a fundamental
parameter of the $SU(2)_L\times U(1)_Y$ electroweak sector of the Standard
Model. Apart from providing a comprehensive test of the electroweak theory at
the quantum loop level, such measurements allow indirect access to new physics
effects at and beyond the TeV scale. After a theoretical introduction and a
brief overview of the three most precise low $Q^2$ weak mixing angle
determinations, we describe the ongoing experimental program and prospects for
future more sensitive studies. We also compare sensitivities of planned and
proposed measurements to physics beyond the Standard Model.


title: The Solution to the Problem of Time in Shape Dynamics

abstract:
  The absence of unique time evolution in Einstein's spacetime description of
gravity leads to the hitherto unresolved `problem of time' in quantum gravity.
Shape Dynamics is an objectively equivalent representation of gravity that
trades spacetime refoliation invariance for three-dimensional conformal
invariance. Its logical completion presented here gives a dimensionless
description of gravitational dynamics. We show that in this framework the
classical problem of time is completely solved. Since a comparable definitive
solution is impossible within the spacetime description, we believe Shape
Dynamics provides a key ingredient for the creation of quantum gravity.


title: Certifying the Potential Energy Landscape

abstract:
  It is highly desirable for a numerical approximation of a stationary point
for a potential energy landscape to lie in the quadratic convergence basin of
that stationary point. However, it is possible that an approximation may lie
only in the linear convergence basin, or even in a chaotic region, and hence
not converge to the actual stationary point when further optimization is
attempted. Proving that a numerical approximation will quadratically converge
to the associated stationary point is termed certifying the numerical
approximation. We employ Smale's \alpha-theory to stationary points, providing
a certification that serves as a mathematical proof that the numerical
approximation does indeed correspond to an actual stationary point, independent
of the precision employed. As a practical example, employing recently developed
certification algorithms, we show how the \alpha-theory can be used to certify
all the known minima and transition states of Lennard-Jones LJ$_{N}$ atomic
clusters for N = 7, ...,14.

categories: cond-mat.soft cond-mat.stat-mech hep-th nlin.CD


title: Radiative Scaling Neutrino Mass with $A_4$ Symmetry

abstract:
  A new idea for neutrino mass was proposed recently, where its smallness is
not due to the seesaw mechanism, i.e. not inversely proportional to some large
mass scale. It comes from a one-loop mechanism with dark matter in the loop
consisting of singlet Majorana fermions $N_i$ with masses of order 10 keV and
neutrino masses are scaled down from them by factors of about $10^{-5}$. We
discuss how this model may be implemented with the non-Abelian discrete
symmetry $A_4$ for neutrino mixing, and consider the phenomenology of $N_i$ as
well as the extra scalar doublet $(\eta^+,\eta^0)$.


title: SecLaaS: Secure Logging-as-a-Service for Cloud Forensics

abstract:
  Cloud computing has emerged as a popular computing paradigm in recent years.
However, today's cloud computing architectures often lack support for computer
forensic investigations. Analyzing various logs (e.g., process logs, network
logs) plays a vital role in computer forensics. Unfortunately, collecting logs
from a cloud is very hard given the black-box nature of clouds and the
multi-tenant cloud models, where many users share the same processing and
network resources. Researchers have proposed using log API or cloud management
console to mitigate the challenges of collecting logs from cloud
infrastructure. However, there has been no concrete work, which shows how to
provide cloud logs to investigator while preserving users' privacy and
integrity of the logs. In this paper, we introduce Secure-Logging-as-a-Service
(SecLaaS), which stores virtual machines' logs and provides access to forensic
investigators ensuring the confidentiality of the cloud users. Additionally,
SeclaaS preserves proofs of past log and thus protects the integrity of the
logs from dishonest investigators or cloud providers. Finally, we evaluate the
feasibility of the scheme by implementing SecLaaS for network access logs in
OpenStack - a popular open source cloud platform.


title:
Imaging starspot evolution on Kepler target KIC 5110407 using light
  curve inversion

abstract:
  The Kepler target KIC 5110407, a K-type star, shows strong quasi-periodic
light curve fluctuations likely arising from the formation and decay of spots
on the stellar surface rotating with a period of 3.4693 days. Using an
established light-curve inversion algorithm, we study the evolution of the
surface features based on Kepler space telescope light curves over a period of
two years (with a gap of .25 years). At virtually all epochs, we detect at
least one large spot group on the surface causing a 1-10% flux modulation in
the Kepler passband. By identifying and tracking spot groups over a range of
inferred latitudes, we measured the surface differential rotation to be much
smaller than that found for the Sun. We also searched for a correlation between
the seventeen stellar flares that occurred during our observations and the
orientation of the dominant surface spot at the time of each flare. No
statistically-significant correlation was found except perhaps for the very
brightest flares, suggesting most flares are associated with regions devoid of
spots or spots too small to be clearly discerned using our reconstruction
technique. While we may see hints of long-term changes in the spot
characteristics and flare statistics within our current dataset, a longer
baseline of observation will be needed to detect the existence of a magnetic
cycle in KIC 5110407.


title: Determination of the X(3872) meson quantum numbers

abstract:
  The quantum numbers of the X(3872) meson are determined to be JPC = 1++ based
on angular correlations in B+ to X(3872) K+ decays, where X(3872) to pi+pi-
J/psi and J/psi to \mu+\mu-. The data correspond to 1.0 fb-1 of pp collisions
collected by the LHCb detector. The only alternative assignment allowed by
previous measurements, JPC=2-+, is rejected with a confidence level equivalent
to more than eight Gaussian standard deviations using the likelihood-ratio test
in the full angular phase space. This result favors exotic explanations of the
X(3872) state.


title:
Fourier transform spectroscopy around 3 microns with a broad difference
  frequency comb

abstract:
  We characterize a new mid-infrared frequency comb generator based on
difference frequency generation around 3.2 microns. High power per comb mode
(>10-7 W/mode) is obtained over a broad spectral span (>700 nm). The source is
used for direct absorption spectroscopy with a Michelson-based Fourier
transform interferometer.


title: Smoothing properties of inhomogeneous equations via canonical transforms

abstract:
  The paper describes a new approach to global smoothing problems for
inhomogeneous dispersive evolution equations based on an idea of canonical
transformation. In our previous papers, we introduced such a method to show
global smoothing estimates for homogeneous dispersive equations. It is
remarkable that this method allows us to carry out a global microlocal
reduction of equations to some low dimensional model cases. The purpose of this
paper is to pursue the same treatment for inhomogeneous equations. Especially,
time-global smoothing estimates for the operator $a(D_x)$ with lower order
terms are the benefit of our new method.


title: Characterizing heterogeneous dynamics at hydrated electrode surfaces

abstract:
  In models of Pt 111 and Pt 100 surfaces in water, motions of molecules in the
first hydration layer are spatially and temporally correlated. To interpret
these collective motions, we apply quantitative measures of dynamic
heterogeneity that are standard tools for considering glassy systems.
Specifically, we carry out an analysis in terms of mobility fields and
distributions of persistence times and exchange times. In so doing, we show
that dynamics in these systems is facilitated by transient disorder in
frustrated two-dimensional hydrogen bonding networks. The frustration is the
result of unfavorable geometry imposed by strong metal-water bonding. The
geometry depends upon the structure of the underlying metal surface. Dynamic
heterogeneity of water on the Pt 111 surface is therefore qualitatively
different than that for water on the Pt 100 surface. In both cases, statistics
of this adlayer dynamic heterogeneity responds asymmetrically to applied
voltage.


title:
Reconstruction of the Tunguska Event of 1908: Neither an Asteroid, Nor a
  Comet Core

abstract:
  The Tunguska explosion occurred in the morning of June 30, 1908, in Central
Siberia, some 800 km NNW from Lake Baikal. It devastated the forested area of
2150 sq. km, flattening and scorching some 30 million trees. Before this, a
luminous body flew overhead in the cloudless sky. The air waves from the
explosion were recorded as far as in London. The object that flew that morning
over Siberia is usually designated the "Tunguska meteorite" or - more
cautiously - the "Tunguska space body" (TSB). Certainly, this body was
dangerous: the taiga was leveled over an area twice as large as New York City.
The whole number of Tunguska hypotheses reaches a hundred, or so. But few of
them have been built according to the standards of science and with due
consideration of empirical data. There is also a serious methodological problem
that is, as a rule, overlooked: the need to take into consideration all
empirical data and to reconstruct the Tunguska event before building any models
of it. Such a reconstruction is essential - since the consequences of this
event are many and varied. The main Tunguska traces may be grouped and listed
as follows: (a) material traces; (b) instrumental traces; (c) informational
traces. To be sure that a proposed theory is correct, the scientist must check
it against all the three types of Tunguska evidence. Having reconstructed the
Tunguska event with due attention to all the evidence, we have to conclude that
it could not have been an asteroid or a comet core. There seems to exist in
space another type of dangerous space objects, whose nature still remains
unknown.


title: Wireless Intrusion Detection Systems(WIDS)

abstract:
  The rapid proliferation of wireless networks and mobile computing
applications has changed the landscape of network security,the wireless
networks have changed the way business, organizations work and offered a new
range of possibilities and flexibilities; It is clear that wireless solutions
are transforming the way we work and live. Employees are able to keep in touch
with their e-mail, calendar and employer from mobile devices, but on the other
hands they introduced a new security threats appeared. While an attacker needs
physical access to a wired network in order to gain access to the network and
to accomplish his goals, a wireless network allows anyone within its range to
passively monitor the traffic or even start an attack,one of the
countermeasures that can be used is the intrusion detection systems in order to
allow us to know both the threats affecting our wireless network and our system
vulnerabilities in order to prevent those attackers, the IDS its main purpose
is to manage the system and its operations and Its duty depends on .


title: Nonlocal PNJL models and heavy hybrid stars

abstract:
  Nonlocal PNJL models allow for a detailed description of chiral quark
dynamics with running quark masses and wave function renormalization in
accordance with lattice QCD (LQCD) in vacuum. Their generalization to finite
temperature T and chemical potential \mu{} allows to reproduce the
\mu-dependence of the pseudocritical temperature from LQCD when a nonvanishing
vector meson coupling is adjusted. This restricts the region for the critical
endpoint in the QCD phase diagram and stiffens the quark matter equation of
state (EoS). It is demonstrated that the construction of a hybrid EoS for
compact star applications within a two-phase approach employing the nonlocal
PNJL EoS and an advanced hadronic EoS leads to the masquerade problem. A
density dependence of the vector meson coupling is suggested as a possible
solution which can be adjusted in a suitable way to describe hybrid stars with
a maximum mass in excess of 2 M_sun with a possible early onset of quark
deconfinement even in the cores of typical (M ~ 1.4 M_sun) neutron stars.


title: The Role of Information Diffusion in the Evolution of Social Networks

abstract:
  Every day millions of users are connected through online social networks,
generating a rich trove of data that allows us to study the mechanisms behind
human interactions. Triadic closure has been treated as the major mechanism for
creating social links: if Alice follows Bob and Bob follows Charlie, Alice will
follow Charlie. Here we present an analysis of longitudinal micro-blogging
data, revealing a more nuanced view of the strategies employed by users when
expanding their social circles. While the network structure affects the spread
of information among users, the network is in turn shaped by this communication
activity. This suggests a link creation mechanism whereby Alice is more likely
to follow Charlie after seeing many messages by Charlie. We characterize users
with a set of parameters associated with different link creation strategies,
estimated by a Maximum-Likelihood approach. Triadic closure does have a strong
effect on link formation, but shortcuts based on traffic are another key factor
in interpreting network evolution. However, individual strategies for following
other users are highly heterogeneous. Link creation behaviors can be summarized
by classifying users in different categories with distinct structural and
behavioral characteristics. Users who are popular, active, and influential tend
to create traffic-based shortcuts, making the information diffusion process
more efficient in the network.


title:
Coupled backward- and forward-propagating solitons in a composite
  right/left-handed transmission line

abstract:
  We study the coupling between backward- and forward-propagating wave modes,
with the same group velocity, in a composite right/left-handed nonlinear
transmission line. Using an asymptotic multiscale expansion technique, we
derive a system of two coupled nonlinear Schr{\"o}dinger equations governing
the evolution of the envelopes of these modes. We show that this system
supports a variety of backward- and forward propagating vector solitons, of the
bright-bright, bright-dark and dark-bright type. Performing systematic
numerical simulations in the framework of the original lattice that models the
transmission line, we study the propagation properties of the derived vector
soliton solutions. We show that all types of the predicted solitons exist, but
differ on their robustness: only bright-bright solitons propagate undistorted
for long times, while the other types are less robust, featuring shorter
lifetimes. In all cases, our analytical predictions are in a very good
agreement with the results of the simulations, at least up to times of the
order of the solitons' lifetimes.