title:
On $\gamma$-vectors and the derivatives of the tangent and secant
  functions

abstract:
  In this paper we consider the gamma-vectors of the types A and B Coxeter
complexes as well as the gamma-vectors of the types A and B associahedrons. We
show that these gamma-vectors can be obtained by using derivative polynomials
of the tangent and secant functions. A grammatical description for these
gamma-vectors is discussed. Moreover, we also present a grammatical description
for the well known Legendre polynomials and Chebyshev polynomials of both
kinds.


title:
Comparison of several reweighted l1-algorithms for solving cardinality
  minimization problems

abstract:
  Reweighted l1-algorithms have attracted a lot of attention in the field of
applied mathematics. A unified framework of such algorithms has been recently
proposed by Zhao and Li. In this paper we construct a few new examples of
reweighted l1-methods. These functions are certain concave approximations of
the l0-norm function. We focus on the numerical comparison between some new and
existing reweighted l1-algorithms. We show how the change of parameters in
reweighted algorithms may affect the performance of the algorithms for finding
the solution of the cardinality minimization problem. In our experiments, the
problem data were generated according to different statistical distributions,
and we test the algorithms on different sparsity level of the solution of the
problem. Our numerical results demonstrate that the reweighted l1-method is one
of the efficient methods for locating the solution of the cardinality
minimization problem.


title:
A new modeling approach to the safety evaluation of N-modular redundant
  computer systems in presence of imperfect maintenance

abstract:
  A large number of safety-critical control systems are based on N-modular
redundant architectures, using majority voters on the outputs of independent
computation units. In order to assess the compliance of these architectures
with international safety standards, the frequency of hazardous failures must
be analyzed by developing and solving proper formal models. Furthermore, the
impact of maintenance faults has to be considered, since imperfect maintenance
may degrade the safety integrity level of the system. In this paper we present
both a failure model for voting architectures based on Bayesian Networks and a
maintenance model based on Continuous Time Markov Chains, and we propose to
combine them according to a compositional multiformalism modeling approach in
order to analyze the impact of imperfect maintenance on the system safety. We
also show how the proposed approach promotes the reuse and the interchange of
models as well the interchange of solving tools.


title: Magnonlike dispersion of spin resonance in Ni-doped BaFe$_2$As$_2$

abstract:
  Inelastic neutron scattering measurements on
Ba(Fe$_{0.963}$Ni$_{0.037}$)$_2$As$_2$ manifest a neutron spin resonance in the
superconducting state with anisotropic dispersion within the Fe layer. Whereas
the resonance is sharply peaked at Q$_{AFM}$ along the orthorhombic a axis, the
resonance disperses upwards away from Q$_{AFM}$ along the b axis. In contrast
to the downward dispersing resonance and hour-glass shape of the spin
excitations in superconducting cuprates, the resonance in electron-doped
BaFe$_2$As$_2$ compounds possesses a magnon-like upwards dispersion.


title: The Egg of Columbus for making the world toughest fibres

abstract:
  A great flourish of interest in the development of new high-strength and
high-toughness materials is taking place in contemporary materials science,
with the aim of surpassing the mechanical properties of commercial
high-performance fibres. Recently, macroscopic buckypapers, nanotube bundles
and graphene sheets have been manufactured. While their macroscopic strength
remains 1-2 orders of magnitude lower than their theoretical strength, and is
thus comparable to that of current commercial fibres, recent progress has been
made in significantly increasing toughness. In particular, researchers have
produced extremely tough nanotube fibres with toughness modulus values of up to
570 J/g, 870 J/g and very recently, including graphene, reaching 970 J/g, thus
well surpassing that of spider silk (170 J/g, with a record for a giant
riverine orb spider of 390 J/g and Kevlar (80 J/g). In this letter, thanks to a
new paradigm based on structural mechanics rather than on materials science, we
present the Egg of Columbus for making fibres with unprecedented toughness: a
slider, in the simplest form just a knot, is introduced as smart frictional
element to dissipate energy and in general to reshape the fibre constitutive
law, showing evidence of a previously hidden toughness, strictly related to the
specific strength of the material. The result is a nearly perfectly plastic
constitutive law, with a shape mimicking that of spider silk. The proof of
concept is experimentally realized making the world toughest fibre, increasing
the toughness modulus of a commercial Endumax fibre from 44 J/g up to 1070 J/g.
The maximal achievable toughness is expected for graphene, with an ideal value
of 100000 J/g.


title: Dimensional analysis using toric ideals

abstract:
  Classical dimensional analysis is one of the cornerstones of qualitative
physics and is also used in the analysis of engineering systems, for example in
engineering design. The basic power product relationship in dimensional
analysis is identical to one way of defining toric ideals in algebraic
geometry, a large and growing field. This paper exploits the toric
representation to provide a method for automatic dimensional analysis for
engineering systems. In particular all "primitive", invariants for a particular
problem, in a well defined sense, can be found using such methods.


title: A PDE-like Toy-Model of Territory Working

abstract:
  This note introduces a PDE-like Toy-Model that embeds several aspects of
Territory Working. The long term goal is to build a software tool that behaves
like a Territory, and in particular that incorporates its
multi-scale-in-time-and-space nature, in order to make simulations, to explore
scenarios, to foresee policy impacts, to help to make a decision when facing a
change in the environment or in cultural behavior, {\it etc.}. The aim of this
note is prove that the concept of building a model that couple Systemic
Approach and PDE tools to achieve the evoked long term goal is possible.


title:
Multistationarity in sequential distributed multisite phosphorylation
  networks

abstract:
  Multisite phosphorylation networks are encountered in many intracellular
processes like signal transduction, cell-cycle control or nuclear signal
integration. In this contribution networks describing the phosphorylation and
dephosphorylation of a protein at $n$ sites in a sequential distributive
mechanism are considered. Multistationarity (i.e.\ the existence of at least
two positive steady state solutions of the associated polynomial dynamical
system) has been analyzed and established in several contributions. It is, for
example, known that there exist values for he rate constants where
multistationarity occurs. However, nothing else is known about these rate
constants.
  Here we present a sign condition that is necessary and sufficient for
multistationarity in $n$-site sequential, distributive phosphorylation. We
express this sign condition in terms of linear systems and show that solutions
of these systems define rate constants where multistationarity is possible. We
then present, for $n\geq 2$, a collection of {\em feasible} linear systems and
hence give a new and independent proof that multistationarity is possible for
$n\geq 2$. Moreover, our results allow to explicitly obtain values for the rate
constants where multistationarity is possible. Hence we believe that, for the
first time, a systematic exploration of the region in parameter space where
multistationarity occurs has become possible.One consequence of our work is
that, for any pair of steady states, the ratio of the steady state
concentrations of kinase-substrate complexes equals that of
phosphatase-substrate complexes.


title:
Ultraviolet Renormalization of the Nelson Hamiltonian through Functional
  Integration

abstract:
  Starting from the N-particle Nelson Hamiltonian defined by imposing an
ultraviolet cutoff, we perform ultraviolet renormalization by showing that in
the zero cutoff limit a self-adjoint operator exists after a logarithmically
divergent term is subtracted from the original Hamiltonian. We obtain this term
as the diagonal part of a pair interaction appearing in the density of a Gibbs
measure derived from the Feynman-Kac representation of the Hamiltonian. Also,
we show existence of a weak coupling limit of the renormalized Hamiltonian and
derive an effective Yukawa interaction potential between the particles.


title: Low-rank optimization for distance matrix completion

abstract:
  This paper addresses the problem of low-rank distance matrix completion. This
problem amounts to recover the missing entries of a distance matrix when the
dimension of the data embedding space is possibly unknown but small compared to
the number of considered data points. The focus is on high-dimensional
problems. We recast the considered problem into an optimization problem over
the set of low-rank positive semidefinite matrices and propose two efficient
algorithms for low-rank distance matrix completion. In addition, we propose a
strategy to determine the dimension of the embedding space. The resulting
algorithms scale to high-dimensional problems and monotonically converge to a
global solution of the problem. Finally, numerical experiments illustrate the
good performance of the proposed algorithms on benchmarks.


title: On the Choi-Effros multiplication

abstract:
  A short proof is given for the well-known Choi-Effros theorem on the
structure of ranges of completely positive projections.


title:
Graphene-mediated exchange coupling between cobaltocene and magnetic
  substrates

abstract:
  Using first-principles calculations we demonstrate sizable exchange coupling
between a magnetic molecule and a magnetic substrate via a graphene layer. As a
model system we consider cobaltocene (CoCp$_2$) adsorbed on graphene deposited
on Ni(111). We find that the magnetic coupling between the molecule and the
substrate is antiferromagnetic and varies considerably depending on the
molecule structure, the adsorption geometry, and the stacking of graphene on
Ni(111). We show how this coupling can be tuned by intercalating a magnetic
monolayer, e.g. Fe or Co, between graphene and Ni(111). We identify the leading
mechanism responsible for the coupling to be the spatial and energy matching of
the frontier orbitals of CoCp$_2$ and graphene close to the Fermi level, and we
demonstrate the role of graphene as an electronic decoupling layer, yet
allowing spin communication between molecule and substrate.


title:
MCMC sampling colourings and independent sets of G(n,d/n) near the
  uniqueness threshold

abstract:
  Sampling from Gibbs distribution is a central problem in computer science as
well as in statistical physics. In this work we focus on the k-colouring model}
and the hard-core model with fugacity \lambda when the underlying graph is an
instance of Erdos-Renyi random graph G(n,p), where p=d/n and d is fixed.
  We use the Markov Chain Monte Carlo method for sampling from the
aforementioned distributions. In particular, we consider Glauber (block)
dynamics. We show a dramatic improvement on the bounds for rapid mixing in
terms of the number of colours and the fugacity for the corresponding models.
For both models the bounds we get are only within small constant factors from
the conjectured ones by the statistical physicists.
  We use Path Coupling to show rapid mixing. For k and \lambda in the range of
our interest the technical challenge is to cope with the high degree vertices,
i.e. vertices of degree much larger than the expected degree d. The usual
approach to this problem is to consider block updates rather than single vertex
updates for the Markov chain. Taking appropriately defined blocks the effect of
high degree vertices somehow diminishes. However, devising such a construction
of blocks is a highly non trivial task.
  We develop for a first time a weighting schema for the paths of the
underlying graph. Vertices which belong to "light" paths, only, can be placed
at the boundaries of the blocks. Then the tree-like local structure of G(n,d/n)
allows the construction of simple structured blocks.


title:
Competing effects of interactions in the adsorbed and activated states
  on surface diffusion at low temperatures

abstract:
  The competing influence of two types of interactions on surface diffusion is
investigated: one of them, epsilon, acts between adsorbed particles, while the
other one, eta, between activated and adsorbed particles. To this end, a
specific lattice-gas model on a triangular, square, and hexagonal lattice is
considered with an attractive epsilon and an attractive or repulsive eta, both
restricted to nearest neighbors. For all three lattices the influence is
qualitatively the same. Namely, when eta is neglected, then epsilon is shown to
decelerate diffusion with a rate exponential in epsilon and inverse
temperature. Moreover, when eta is present and epsilon is fixed, then a
sufficiently attractive eta (relative to epsilon) accelerates diffusion
exponentially fast in eta and inverse temperature. However, quite surprisingly,
a repulsive or slightly attractive eta has practically no effect on diffusion.
Finally, when eta is set proportional to epsilon via a parameter $a$, surface
diffusion is exponentially accelerated (decelerated) for $a$ above (below) a
threshold value equal to 4, 5/4, and 7/8 for the three lattices. Thus, an eta
of strength comparable to epsilon is enough to boost diffusion on the square
and hexagonal lattices, while an eta of a rather large strength is needed for
the boost on the triangular lattice.


title:
Measurement of jet $p_{\mathrm{T}}$ spectra in Pb-Pb collisions at
  $\sqrt{s_{\mathrm{NN}}}=2.76~\mathrm{TeV}$ with the ALICE detector at the LHC

abstract:
  Reconstruction of jets in high-energy heavy-ion collisions is challenging due
to the large and fluctuating background coming from the underlying event. We
report results on full jet reconstruction, obtained from data collected in 2011
by the ALICE detector at LHC for Pb-Pb collisions at
$\sqrt{s_{\mathrm{NN}}}=2.76~\mathrm{TeV}$. The analysis makes use of the
tracking system and the electromagnetic calorimeter. Signal jets, which come
from hard scattered partons, are reconstructed using the anti-$k_{\mathrm{T}}$
jet finder algorithm. The average background is subtracted on a jet-by-jet
basis to reduce the contribution to the jet reconstructed energy coming from
the underlying event. The jet spectrum is corrected to account for fluctuations
in the background momentum density and detector effects through unfolding.


title:
Resampling Approach for the Calculation Processes and Information
  Systems Models Estimation

abstract:
  The work is devoted to the analysis of the Resampling method proposed by A.
Andronov and to the analysis of the Resampling method application possibility
to the estimation and simulation of the calculation and logical systems
reliability. The work Simple and Hierarchical method properties are considered,
algorithms for variance are shown. The methods are applied for processes in the
multitask operation system and queries to database analysis, a comparison with
the classical method, that uses the empirical distribution functions, is made.
Numerical examples illustrate the influence of different factors on the
Resampling method efficiency.
  The task of the sample size optimization has been considered. The dynamic
programming method is applied to minimize the variance of the Resampling
estimator. Optimization is applied for the analysis of queries to database, the
numerical example illustrates the value of optimization.
  The case of partially known distributions is considered. It is shown how to
use the Resampling approach in the case when the distributions of some input
variables are known. The method is applied to database query analysis and a
comparison with Hierarchical Resampling is made.
  The construction of the Resampling confidence intervals is considered. The
algorithm for construction of the Resampling confidence intervals is shown and
actual coverage probabilities are calculated. Examples for the multitask
operation system analysis illustrate the calculation of the actual coverage
probability algorithm.


title: Resampling Approach to the Estimation of Reliability Systems

abstract:
  The article is devoted to the resampling approach application to the
reliability problems. This approach to reliability problems was first proposed
by Ivnitsky (1967). Resampling is intensive statistical computer method, which
is non-parametrical, that uses initial samples data in different combinations
to simulate the process many times and get finally the estimator of the
characteristics of interest. At the present paper simple resampling,
hierarchical resampling, the case of one sample for several variables, the case
of partially known distributions, analysis of degradation flow, analysis of
degradation-renewal process, construction of confidence intervals are
described. All those resampling application cases can be applied successfully
to solve the reliability problems as an alternative to classical methods.


title: Products of Beta distributed random variables

abstract:
  This is an expository note on useful expressions for the density function of
a product of independent random variables where each variable has a Beta
distribution.


title: Hardware Implementation of Algorithm for Cryptanalysis

abstract:
  Cryptanalysis of block ciphers involves massive computations which are
independent of each other and can be instantiated simultaneously so that the
solution space is explored at a faster rate. With the advent of low cost Field
Programmable Gate Arrays, building special purpose hardware for computationally
intensive applications has now become possible. For this the Data Encryption
Standard is used as a proof of concept. This paper presents the design for
Hardware implementation of DES cryptanalysis on FPGA using exhaustive key
search. Two architectures viz. Rolled and Unrolled DES architecture are
compared and based on experimental result the Rolled architecture is
implemented on FPGA. The aim of this work is to make cryptanalysis faster and
better.


title: Gaussian Process for star and planet characterisation

abstract:
  The study of exoplanetary atmospheres epitomises a continuous quest for
higher accuracy measurements. Systematic effects and noise associated with both
the stellar activity and the instrument can bias the results and thus limit the
precision of the analysis. To reach a high photometric and spectroscopic
precision, it is therefore essential to correct for these effects. We present
here a novel non-parametric approach, named Gaussian Process method for Star
Characterization (GPSC), to remove effects of stellar activity and instrumental
systematics on planetary signals, with a view to preserve the atmospheric
contribution which can be as small as 10$^{-4}$ or even 10$^{-5}$ the flux of
the star. We applied our method to data recorded with Kepler, focussing on a
sample of lightcurves with different effective temperatures and flux
modulations. We found that GPSC can very effectively correct for the short and
long term stellar activity and instrumental systematics. Additionally we run
the GPSC on both real and simulated transit data, finding transit depths
consistent with the original ones. Consequently we considered 10 hours of
continuous observations: daily, every other day and weekly, and we used the
GPSC to reconstruct the lightcurves. When data are recorded more frequently
than once every five days we found that our approach is able to extrapolate the
stellar flux at the 10$^{-4}$ level compared to the full stellar flux. These
results show a great potential of GPSC to isolate the relevant astrophysical
signal and achieve the precision needed for the correction of short and long
term stellar activity.


title: Focusing polychromatic light through strongly scattering media

abstract:
  We demonstrate feedback-optimized focusing of spatially coherent
polychromatic light after transmission through strongly scattering media, and
describe the relationship between optimized focus intensity and initial
far-field speckle contrast. Optimization is performed using a MEMS spatial
light modulator with camera-based or spectrometer-based feedback. We observe
that the spectral bandwidth of the optimized focus depends on characteristics
of the feedback signal. We interpret this dependence as a modification in the
number of spectral modes transmitted by the sample, and introduce a simple
model for polychromatic focus enhancement that is corroborated by experiment
with calibrated samples.


title:
Asymptotic evaluation of bosonic probability amplitudes in linear
  unitary networks in the case of large number of bosons

abstract:
  An asymptotic analytical approach is proposed for bosonic probability
amplitudes in unitary linear networks, such as the optical multiport devices
for photons. The asymptotic approach applies for large number of bosons $N\gg
M$ in the $M$-mode network, where $M$ is finite. The probability amplitudes of
$N$ bosons unitarily transformed from the input modes to the output modes of a
unitary network are expressed through a multidimensional integral with the
integrand containing a large parameter (N) in the exponent. The integral
representation allows an asymptotic estimate of bosonic probability amplitudes
up to a multiplicative error of order 1/N by the saddle point method. The
estimate depends on solution of the scaling problem for the $M\times
M$-dimensional unitary network matrix: to find the left and right diagonal
matrices which scale the unitary matrix to a matrix which has specified row and
column sums (equal, respectively, to the distributions of bosons in the input
and output modes). The scaled matrices give the saddle points of the integral.
For simple saddle points, an explicit formula giving the asymptotic estimate of
bosonic probability amplitudes is derived. Performance of the approximation and
the scaling of the relative error with N are studied for two-mode network (the
beam-splitter), where the saddle-points are roots of a quadratic and an exact
analytical formula for the probability amplitudes is available, and for
three-mode network (the tritter).

categories: quant-ph cond-mat.quant-gas math-ph math.MP


title:
Search for New Heavy Higgs Boson in B-L model at the LHC using Monte
  Carlo Simulation

abstract:
  The aim of this work is to search for a new heavy Higgs boson in the B-L
extension of the Standard Model at LHC using the data produced from simulated
collisions between two protons at different center of mass energies by Monte
Carlo event generator programs to find new Higgs boson signatures at the LHC.
Also we study the production and decay channels for Higgs boson in this model
and its interactions with the other new particles of this model namely the new
neutral gauge massive boson and the new fermionic right-handed heavy neutrinos .


title: Monte Carlo Event Generators

abstract:
  Monte Carlo event generators are essential components of almost all
experimental analyses and are also widely used by theorists and experiments to
make predictions and preparations for future experiments. They are all too
often used as "black boxes", without sufficient consideration of their
component models or their reliability. In this set of three lectures we hope to
open the box and explain the physical bases behind the models they use. We
focus primarily on the general features of parton showers, hadronization and
underlying event generation.


title:
On the gravitational Chern-Simons action as entropy functional for
  three-manifolds, and the demystification of the Ho\v{r}ava-Lifshitz gravity

abstract:
  We determine the more general geometrical flow in the space of metrics
corresponding to the steepest descent for the three-dimensional gravitational
Chern-Simons action, extending the results previously considered in
  Class. Quantum Grav. 25 (2008) 165019, and reveling another trouble with the
four dimensional Ho\v{r}ava-Lifshitz gravity introduced in Phys. Rev. D 79,
084008 (2009), and JHEP 0903, 020 (2009), which attempts to be a candidate for
an UV completion of Einstein general relativity.


title: Cavity cooling of an optically levitated nanoparticle

abstract:
  The ability to trap and to manipulate individual atoms is at the heart of
current implementations of quantum simulations, quantum computing, and
long-distance quantum communication. Controlling the motion of larger particles
opens up yet new avenues for quantum science, both for the study of fundamental
quantum phenomena in the context of matter wave interference, and for new
sensing and transduction applications in the context of quantum optomechanics.
Specifically, it has been suggested that cavity cooling of a single
nanoparticle in high vacuum allows for the generation of quantum states of
motion in a room-temperature environment as well as for unprecedented force
sensitivity. Here, we take the first steps into this regime. We demonstrate
cavity cooling of an optically levitated nanoparticle consisting of
approximately 10e9 atoms. The particle is trapped at modest vacuum levels of a
few millibar in the standing-wave field of an optical cavity and is cooled
through coherent scattering into the modes of the same cavity. We estimate that
our cooling rates are sufficient for ground-state cooling, provided that
optical trapping at a vacuum level of 10e-7 millibar can be realized in the
future, e.g., by employing additional active-feedback schemes to stabilize the
optical trap in three dimensions. This paves the way for a new light-matter
interface enabling room-temperature quantum experiments with mesoscopic
mechanical systems.


title:
Equipartition Gamma-Ray Blazars and the Location of the Gamma-Ray
  Emission Site in 3C 279

abstract:
  Blazar spectral models generally have numerous unconstrained parameters,
leading to ambiguous values for physical properties like Doppler factor delta
or fluid magnetic field B'. To help remedy this problem, a few modifications of
the standard leptonic blazar jet scenario are considered. First, a log-parabola
function for the electron distribution is used. Second, analytic expressions
relating energy loss and kinematics to blazar luminosity and variability,
written in terms of equipartition parameters, imply delta, B', and the
principal electron Lorentz factor gamma'_pk. The external radiation field in a
blazar is approximated by Ly alpha radiation from the broad line region (BLR)
and ~0.1 eV infrared radiation from a dusty torus. When used to model 3C 279
SEDs from 2008 and 2009 reported by Hayashida et al. (2012), we derive delta ~
20-30, B' ~ few G, and total (IR + BLR) external radiation field energy
densities u ~ 0.01 - 0.001 erg/cm^3, implying an origin of the gamma-ray
emission site in 3C 279 at the outer edges of the BLR. This is consistent with
the gamma-ray emission site being located at a distance R <~ Gamma^2 c t_{var}
~ 0.1 (\Gamma/30)^2 (t_{var}/10^4 s) pc from the black hole powering 3C 279's
jets, where t_{var} is the variability time scale of the radiation in the
source frame, and at farther distances for narrow-jet and magnetic_reconnection
models. Excess >~ 5 GeV gamma-ray emission observed with Fermi LAT from 3C 279
challenge the model, opening the possibility of hadronic origins of the
emission. For low hadronic content, absolute jet powers of ~10% of the
Eddington luminosity are calculated.


title: Rest frame of bubble nucleation

abstract:
  Vacuum bubbles nucleate at rest with a certain critical size and subsequently
expand. But what selects the rest frame of nucleation? This question has been
recently addressed in [1] in the context of Schwinger pair production in 1+1
dimensions, by using a model detector in order to probe the nucleated pairs.
The analysis in [1] showed that, for a constant external electric field, the
adiabatic "in" vacuum of charged particles is Lorentz invariant, and in this
case pairs tend to nucleate preferentially at rest with respect to the
detector. Here, we sharpen this picture by showing that the typical relative
velocity between the frame of nucleation and that of the detector is at most of
order \Delta v ~ S_E^{-1/3} << 1. Here, S_E >> 1 is the action of the instanton
describing pair creation. The bound \Delta v coincides with the minimum
uncertainty in the velocity of a non-relativistic charged particle embedded in
a constant electric field. A velocity of order \Delta v is reached after a time
interval of order \Delta t ~ S_E^{-1/3} r_0 << r_0 past the turning point in
the semiclassical trajectory, where r_0 is the size of the instanton. If the
interaction takes place in the vicinity of the turning point, the semiclassical
description of collision does not apply. Nonetheless, we find that even in this
case there is still a strong asymmetry in the momentum transferred from the
nucleated particles to the detector, in the direction of expansion after the
turning point. We conclude that the correlation between the rest frame of
nucleation and that of the detector is exceedingly sharp.


title:
Understanding electron behavior in strained graphene as a reciprocal
  space distortion

abstract:
  The behavior of electrons in strained graphene is usually described using
effective pseudomagnetic fields in a Dirac equation. Here we consider the
particular case of a spatially constant strain. Our results indicate that
lattice corrections are easily understood using a strained reciprocal space, in
which the whole energy dispersion is simply shifted and deformed. This leads to
a directional dependent Fermi velocity without producing pseudomagnetic fields.
The corrections due to atomic wavefunction overlap changes tend to compensate
such effects. Also, the analytical expressions for the shift of the Dirac
points as well as the corresponding Dirac equation are found. In view of the
former results, we discuss the range of applicability of the usual approach of
considering pseudomagnetic fields in a Dirac equation derived from the old
Dirac points of the unstrained lattice. Such considerations are important if a
comparison is desired with experiments or numerical simulations.


title: Assessing Relative Volatility/Intermittency/Energy Dissipation

abstract:
  We introduce the notion of relative volatility/intermittency and demonstrate
how relative volatility statistics can be used to estimate consistently the
temporal variation of volatility/intermittency when the data of interest are
generated by a non-semimartingale, or a Brownian semistationary process in
particular. This estimation method is motivated by the assessment of relative
energy dissipation in empirical data of turbulence, but it is also applicable
in other areas. We develop a probabilistic asymptotic theory for realised
relative power variations of Brownian semistationary processes, and introduce
inference methods based on the theory. We also discuss how to extend the
asymptotic theory to other classes of processes exhibiting stochastic
volatility/intermittency. As an empirical application, we study relative energy
dissipation in data of atmospheric turbulence.


title: Solitons and thermal fluctuations in strongly nonlinear solids

abstract:
  We study a chain of anharmonic springs with tunable power law interactions as
a minimal model to explore the propagation of strongly non-linear solitary wave
excitations in a background of thermal fluctuations. By treating the solitary
waves as quasi-particles, we derive an effective Langevin equation and obtain
their damping rate and thermal diffusion. These analytical findings compare
favorably against numerical results from a Langevin dynamic simulation. In our
chains composed of two sided non-linear springs, we report the existence of an
expansion solitary wave (anti-soliton) in addition to the compressive solitary
waves observed for non-cohesive macroscopic particles.


title: Distance-Sensitive Property Testing Lower Bounds

abstract:
  In this paper, we consider several property testing problems and ask how the
query complexity depends on the distance parameter $\eps$. We achieve new lower
bounds in this setting for the problems of testing whether a function is
monotone and testing whether the function has low Fourier degree. For
monotonicity testing, our lower bound matches the recent upper bound of
Chakrabarty and Seshadhri.


title:
Birational positivity in dimension 4 (with an appendix by Fr\'ed\'eric
  Campana)

abstract:
  In this paper we prove that for a nonsingular projective variety of dimension
at most 4 and with non-negative Kodaira dimension, the Kodaira dimension of
coherent subsheaves of $\Omega^p$ is bounded from above by the Kodaira
dimension of the variety. This implies the finiteness of the fundamental group
for such an $X$ provided that $X$ has vanishing Kodaira dimension and
non-trivial holomorphic Euler characteristic.


title:
Coupled Nd and B' spin ordering in the double perovskites Nd2NaB'O6 (B'
  = Ru, Os)

abstract:
  We present a neutron powder diffraction study of the monoclinic double
perovskite systems Nd2NaB'O6 (B' = Ru, Os), with magnetic atoms occupying both
the A and B' sites. Our measurements reveal coupled spin ordering between the
Nd and B' atoms with magnetic transition temperatures of 14 K for Nd2NaRuO6 and
16 K for Nd2NaOsO6. There is a Type I antiferromagnetic structure associated
with the Ru and Os sublattices, with the ferromagnetic planes stacked along the
c-axis and [110] direction respectively, while the Nd sublattices exhibit
complex, canted antiferromagnetism with different spin arrangements in each
system.


title: A Homogeneous Model of Spinfoam Cosmology

abstract:
  We examine spinfoam cosmology by use of a simple graph adapted to homogeneous
cosmological models. We calculate dynamics in the isotropic limit, and provide
the framework for the aniostropic case. The dynamical behaviour is calculating
transition amplitudes between holomorphic coherent states on a single node
graph. The resultant dynamics is peaked on solutions which have no support on
the zero volume state, indicating that big bang type singularities are avoided
within such models.


title:
Comment on "Protocol for Direct Counterfactual Quantum Communication"
  [arXiv:1206.2042]

abstract:
  I argue that recent "Protocol for Direct Counterfactual Quantum
Communication" by Salih et al. [PRL 110, 170502 (2013), arXiv:1206.2042] is
counterfactual only for one type of the information bit.


title: Massive MIMO for Next Generation Wireless Systems

abstract:
  Multi-user Multiple-Input Multiple-Output (MIMO) offers big advantages over
conventional point-to-point MIMO: it works with cheap single-antenna terminals,
a rich scattering environment is not required, and resource allocation is
simplified because every active terminal utilizes all of the time-frequency
bins. However, multi-user MIMO, as originally envisioned with roughly equal
numbers of service-antennas and terminals and frequency division duplex
operation, is not a scalable technology. Massive MIMO (also known as
"Large-Scale Antenna Systems", "Very Large MIMO", "Hyper MIMO", "Full-Dimension
MIMO" & "ARGOS") makes a clean break with current practice through the use of a
large excess of service-antennas over active terminals and time division duplex
operation. Extra antennas help by focusing energy into ever-smaller regions of
space to bring huge improvements in throughput and radiated energy efficiency.
Other benefits of massive MIMO include the extensive use of inexpensive
low-power components, reduced latency, simplification of the media access
control (MAC) layer, and robustness to intentional jamming. The anticipated
throughput depend on the propagation environment providing asymptotically
orthogonal channels to the terminals, but so far experiments have not disclosed
any limitations in this regard. While massive MIMO renders many traditional
research problems irrelevant, it uncovers entirely new problems that urgently
need attention: the challenge of making many low-cost low-precision components
that work effectively together, acquisition and synchronization for
newly-joined terminals, the exploitation of extra degrees of freedom provided
by the excess of service-antennas, reducing internal power consumption to
achieve total energy efficiency reductions, and finding new deployment
scenarios. This paper presents an overview of the massive MIMO concept and
contemporary research.


title:
Optimal upper and lower bounds for the true and empirical excess risks
  in heteroscedastic least-squares regression

abstract:
  We consider the estimation of a bounded regression function with
nonparametric heteroscedastic noise and random design. We study the true and
empirical excess risks of the least-squares estimator on finite-dimensional
vector spaces. We give upper and lower bounds on these quantities that are
nonasymptotic and optimal to first order, allowing the dimension to depend on
sample size. These bounds show the equivalence between the true and empirical
excess risks when, among other things, the least-squares estimator is
consistent in sup-norm with the projection of the regression function onto the
considered model. Consistency in the sup-norm is then proved for suitable
histogram models and more general models of piecewise polynomials that are
endowed with a localized basis structure.


title: Soliton attenuation and emergent hydrodynamics in fragile matter

abstract:
  Disordered packings of soft grains are fragile mechanical systems that loose
rigidity upon lowering the external pressure towards zero. At zero pressure, we
find that any infinitesimal strain-impulse propagates initially as a non-linear
solitary wave progressively attenuated by disorder. We demonstrate that the
particle fluctuations generated by the solitary-wave decay, can be viewed as a
granular analogue of temperature. Their presence is manifested by two emergent
macroscopic properties absent in the unperturbed granular packing: a finite
pressure that scales with the injected energy (akin to a granular temperature)
and an anomalous viscosity that arises even when the microscopic mechanisms of
energy dissipation are negligible. Consistent with the interpretation of this
state as a fluid-like thermalized state, the shear modulus remains zero.
Further, we follow in detail the attenuation of the initial solitary wave
identifying two distinct regimes : an initial exponential decay, followed by a
longer power law decay and suggest simple models to explain these two regimes.


title: Reliable Deniable Communication: Hiding Messages in Noise

abstract:
  A transmitter Alice may wish to reliably transmit a message to a receiver Bob
over a binary symmetric channel (BSC), while simultaneously ensuring that her
transmission is deniable from an eavesdropper Willie. That is, if Willie
listening to Alice's transmissions over a "significantly noisier" BSC than the
one to Bob, he should be unable to estimate even whether Alice is transmitting.
We consider two scenarios. In our first scenario, we assume that the channel
transition probability from Alice to Bob and Willie is perfectly known to all
parties. Here, even when Alice's (potential) communication scheme is publicly
known to Willie (with no common randomness between Alice and Bob), we prove
that over 'n' channel uses Alice can transmit a message of length O(sqrt{n})
bits to Bob, deniably from Willie. We also prove information-theoretic
order-optimality of this result. In our second scenario, we allow uncertainty
in the knowledge of the channel transition probability parameters. In
particular, we assume that the channel transition probabilities for both Bob
and Willie are uniformly drawn from a known interval. Here, we show that, in
contrast to the previous setting, Alice can communicate O(n) bits of message
reliably and deniably (again, with no common randomness). We give both an
achievability result and a matching converse for this setting. Our work builds
upon the work of Bash et al on AWGN channels (but with common randomness) and
differs from other recent works (by Wang et al and Bloch) in two important ways
- firstly our deniability metric is variational distance (as opposed to
Kullback-Leibler divergence), and secondly, our techniques are significantly
different from these works.


title: Technical report- Evaluation methodology in the REVIT project

abstract:
  The purpose of this technical report is to present a methodological approach
for evaluating the REVIT (http://revit.cti.gr) educational venture as a whole
and assessing the learning effectiveness of the resulting collaborative
e-courses.


title: Characterization of the JUDIDT Readout Electronics for Neutron Detection

abstract:
  The Group for the development of neutron and gamma detectors in the Central
Institute of Engineering, Electronics and Analytics (ZEA-2) at
Forschungszentrum Juelich (FZJ) has developed, in collaboration with European
institutes, an Anger Camera prototype for improving the impact point
reconstruction of neutron tracks. The detector is a chamber filled with
$^3He+CF_4$ gas for neutron capture and subsequent production of a tritium and
a proton. The energy deposition by the ions gives rise to drifting electrons
with an avalanche amplification as they approach a micro-strip anode structure.
The scintillating light, generated during the electron drift and avalanche
stage, is collected by four vacuum photomultipliers. The position
reconstruction is performed via software algorithms. The JUDIDT readout
electronics was modified at ZEA-2 to cope with the data acquisition
requirements of the prototype. The results of the commissioning of the
electronics are here presented and commented.


title:
Studying Inter-Cluster Galaxy Filaments Through Stacking GMBCG Galaxy
  Cluster Pairs

abstract:
  We present a method to study the photometric properties of galaxies in
filaments by stacking the galaxy populations between pairs of galaxy clusters.
Using Sloan Digital Sky Survey data, this method can detect the inter-cluster
filament galaxy overdensity with a significance of $\sim 5 \sigma$ out to
$z=0.40$. Using this approach, we study the $g-r$ color and luminosity
distribution of filament galaxies as a function of redshift. Consistent with
expectation, filament galaxies are bimodal in their color distribution and
contain a larger blue galaxy population than clusters. Filament galaxies are
also generally fainter than cluster galaxies. More interestingly, the observed
filament population seems to show redshift evolution at $0.12<z<0.40$: the blue
galaxy fraction has a trend to increase at higher redshift: a filament "Butcher
Oemler Effect". We test the dependence of the observed filament density on the
richness of the cluster pair: richer clusters are connected by higher density
filaments. We also test the spatial dependence of filament galaxy overdensity:
this quantity decreases when moving away from the inter-cluster axis between a
cluster pair. This method provides an economical way to probe the photometric
properties of filament galaxies and should prove useful for upcoming projects
like the Dark Energy Survey.


title: Non-conformal brane plane waves and entanglement entropy

abstract:
  Following [arXiv:1202.5935 [hep-th]] and [arXiv:1212.4328 [hep-th]], we study
non-conformal brane plane wave backgrounds dual to strongly coupled gauge
theories with constant energy flux and holographic entanglement entropy for
strip subsystems in them. We find that for the strip direction along the
direction of the energy flux, the finite cutoff-independent part of
entanglement entropy can be estimated in terms of a dimensionless combination
of the energy density and the strip dimensions, alongwith an effective
scale-dependent number of degrees of freedom. For the strip orthogonal to the
flux direction, there are indications of phase transitions. We also briefly
discuss NS5-brane backgrounds corresponding to plane wave states in little
string theories.


title:
Observation of Pull-in Instability in Graphene Membranes under
  Interfacial Forces

abstract:
  We present a unique experimental configuration that allows us to determine
the interfacial forces on nearly parallel plates made from the thinnest
possible mechanical structures, single and few layer graphene membranes. Our
approach consists of using a pressure difference across a graphene membrane to
bring the membrane to within ~ 10-20 nm above a circular post covered with SiOx
or Au until a critical point is reached whereby the membrane snaps into
adhesive contact with the post. Continuous measurements of the deforming
membrane with an AFM coupled with a theoretical model allow us to deduce the
magnitude of the interfacial forces between graphene and SiOx and graphene and
Au. The nature of the interfacial forces at ~ 10 - 20 nm separations is
consistent with an inverse fourth power distance dependence, implying that the
interfacial forces are dominated by van der Waals interactions. Furthermore,
the strength of the interactions is found to increase linearly with the number
of graphene layers. The experimental approach can be used to measure the
strength of the interfacial forces for other atomically thin two-dimensional
materials, and help guide the development of nanomechanical devices such as
switches, resonators, and sensors.


title: Bouncing Anisotropic Universes with Varying Constants

abstract:
  We examine the evolution of a closed, homogeneous and anisotropic cosmology
subject to a variation of the fine structure 'constant', \alpha, within the
context of the theory introduced by Bekenstein, Sandvik, Barrow and Magueijo,
which generalises Maxwell's equations and general relativity. The variation of
\alpha permits an effective ghost scalar field, whose negative energy density
becomes dominant at small length scales, leading to a bouncing cosmology. A
thermodynamically motivated coupling which describes energy exchange between
the effective ghost field and the radiation field leads to an expanding,
isotropizing sequence of bounces. In the absence of entropy production we also
find solutions with stable anisotropic oscillations around a static universe.


title: Z' at the LHC: Interference and Finite Width Effects in Drell-Yan

abstract:
  The interference effects between an extra neutral spin-1 Z'-boson and the
Standard Model background in the Drell-Yan channel at the LHC are studied in
detail. The final state with two oppositely charged leptons is considered. The
interference contribution to the new physics signal, currently not fully taken
into account by experimental collaborations in Z'-searches and in the
interpretation of the results, can be substantial. It may affect limits or
discovery prospects of Z' at the LHC. As the Z'-boson interference is
model-dependent, a proper treatment would a priori require a dedicated
experimental analysis for each particular model. Doing so could potentially
improve the sensitivity to new physics, but would require significantly more
experimental effort.
  At the same time, it is shown that one can define an invariant mass window,
valid for a wide range of models, for which the contribution of the
model-dependent interference to the Beyond the Standard Model signal is reduced
to O(10%), comparable to the level of the combined uncertainty from parton
densities and higher order corrections. This quasi-model-independent "magic
cut" does not scale with the mass of the Z'-boson and is approximately constant
over a large range of masses. Such control of the interference effects relies
on not-too-small branching ratios of Z' to leptons (typically of at least a few
percent) which can be suppressed, however, by additional new decay channels of
the Z'; a small width-to-mass ratio alone does not guarantee the interference
to be small over an arbitrary kinematic range. Under the general assumption
that these new decay channels of Z' are not dominant, one can perform
quasi-model-independent analyses, preserving the current scheme used by the
experimental collaborations for the Z'-boson search using the suggested
invariant mass window cut.


title: Staffing Large Service Systems Under Arrival-rate Uncertainty

abstract:
  We consider the problem of staffing large-scale service systems with multiple
customer classes and multiple dedicated server pools under joint
quality-of-service (QoS) constraints. We first analyze the case in which
arrival rates are deterministic and the QoS metric is the probability a
customer is queued, given by the Erlang-C formula. We use the Janssen-Van
Leeuwaarden-Zwart bounds to obtain asymptotically optimal solutions to this
problem. The second model considered is one in which the arrival rates are not
completely known in advance (before the server staffing levels are chosen), but
rather are known via a probability distribution. In this case, we provide
asymptotically optimal solutions to the resulting stochastic integer program,
leveraging results obtained for the deterministic arrivals case.


title: NOON states in trapped ions

abstract:
  We show how NOON states may be generated in ion traps. We use the individual
interaction of light with each of two vibrational modes of the ion to entangle
them. This allows us to generate NOON states with N=8.


title:
The Trace Problem for Toeplitz Matrices and Operators and its Impact in
  Probability

abstract:
  The trace approximation problem for Toeplitz matrices and its applications to
stationary processes dates back to the classic book by Grenander and Szeg\"o,
"Toeplitz forms and their applications". It has then been extensively studied
in the literature.
  In this paper we provide a survey and unified treatment of the trace
approximation problem both for Toeplitz matrices and for operators and describe
applications to discrete- and continuous-time stationary processes.
  The trace approximation problem serves indeed as a tool to study many
probabilistic and statistical topics for stationary models. These include
central and non-central limit theorems and large deviations of Toeplitz type
random quadratic functionals, parametric and nonparametric estimation,
prediction of the future value based on the observed past of the process, etc.
  We review and summarize the known results concerning the trace approximation
problem, prove some new results, and provide a number of applications to
discrete- and continuous-time stationary time series models with various types
of memory structures, such as long memory, anti-persistent and short memory.


title: A permuted random walk exits faster

abstract:
  Let $\sigma$ be a permutation of $\{0,\ldots,n\}$. We consider the Markov
chain $X$ which jumps from $k\neq 0,n$ to $\sigma(k+1)$ or $\sigma(k-1)$,
equally likely. When $X$ is at 0 it jumps to either $\sigma(0)$ or $\sigma(1)$
equally likely, and when $X$ is at $n$ it jumps to either $\sigma(n)$ or
$\sigma(n-1)$, equally likely. We show that the identity permutation maximizes
the expected hitting time of n, when the walk starts at 0. More generally, we
prove that the hitting time of a random walk on a strongly connected
$d$-directed graph is maximized when the graph is the line $[0,n]\cap\Z$ with
$d-2$ self-loops at every vertex and $d-1$ self-loops at 0 and $n$.


title: Entropy currents from holography in hydrodynamics with charge

abstract:
  The holographic interpretation of the hydrodynamic entropy current is
developed for the case of hydrodynamics with a conserved charge. This is
carried out within a framework developed in earlier work, which showed how to
associate entropy currents with horizons in the dual geometry. The entropy
current defined by the event horizon in the dual bulk geometry is calculated.
It is also shown that to second order in the gradient expansion the dual
geometry possesses a unique Weyl-invariant apparent horizon which also defines
an admissable entropy current. At first order both currents coincide with the
result obtained on the basis of a purely hydrodynamic analysis.


title:
Analysis of the trajectory of a sphere moving through a geometric
  constriction

abstract:
  We present a numerical study of the effect that fluid and particle inertia
have on the motion of suspended spherical particles through a geometric
constriction to understand analogous microfluidic settings, such as pinched
flow fractionation devices. The particles are driven by a constant force in a
quiescent fluid, and the constriction (the pinching gap) corresponds to the
space between a plane wall and a second, fixed sphere of the same size (the
obstacle). The results show that, due to inertia and/or the presence of a
geometric constriction the particles attain smaller separations to the
obstacle. We then relate the minimum surface-to-surface separation to the
effect that short-range, repulsive non-hydrodynamic interactions (such as
solid-solid contact due to surface roughness, electrostatic double layer
repulsion, etc.) would have on the particle trajectories. In particular, using
a simple hard-core repulsive potential model for such interactions, we infer
that the particles would experience larger lateral displacements moving through
the pinching gap as inertia increases and/or the aperture of the constriction
decreases. Thus, separation of particles based on differences in density is in
principle possible, owing to the differences in inertia associated with them.
We also discuss the case of significant inertia, in which the presence of a
small construction may hinder separation by reducing inertia effects.


title: Counting approximately-shortest paths in directed acyclic graphs

abstract:
  Given a directed acyclic graph with positive edge-weights, two vertices s and
t, and a threshold-weight L, we present a fully-polynomial time
approximation-scheme for the problem of counting the s-t paths of length at
most L. We extend the algorithm for the case of two (or more) instances of the
same problem. That is, given two graphs that have the same vertices and edges
and differ only in edge-weights, and given two threshold-weights L_1 and L_2,
we show how to approximately count the s-t paths that have length at most L_1
in the first graph and length at most L_2 in the second graph. We believe that
our algorithms should find application in counting approximate solutions of
related optimization problems, where finding an (optimum) solution can be
reduced to the computation of a shortest path in a purpose-built auxiliary
graph.


title: Physics of Gluon Helicity Contribution to Proton Spin

abstract:
  The total gluon helicity in a polarized proton, measurable in high-energy
scattering, is shown to be the large momentum limit of a gauge-invariant but
non-local, frame-dependent gluon spin $\vec{E}\times \vec{A}_\perp$ in QCD.
This opens a door for a non-perturbative calculation of this quantity in
lattice QCD, and also justifies using free-field expressions in the light-cone
gauge as physical observables.


title: Designing the W3C Open Annotation Data Model

abstract:
  The Open Annotation Core Data Model specifies an interoperable framework for
creating associations between related resources, called annotations, using a
methodology that conforms to the Architecture of the World Wide Web. Open
Annotations can easily be shared between platforms, with sufficient richness of
expression to satisfy complex requirements while remaining simple enough to
also allow for the most common use cases, such as attaching a piece of text to
a single web resource. This paper presents the W3C Open Annotation Community
Group specification and the rationale behind the scoping and technical
decisions that were made. It also motivates interoperable Annotations via use
cases, and provides a brief analysis of the advantages over previous
specifications.


title: X(3872) and its production at hadron colliders

abstract:
  We evaluate the production cross sections of $X(3872)$ at the LHC and
Tevatron at NLO in $\alpha_s$ in NRQCD by assuming that the short-distance
production proceeds dominantly through its $\chi_{c1}'$ component in our
$\chi_{c1}'\mbox{-}D^0\bar{D}^{*0}$ mixing model for $X(3872)$. The outcomes of
the fits to the CMS $p_T$ distribution can well account for the recent ATLAS
data in a much larger range of transverse momenta
($10~\mbox{GeV}<p_T<70~\mbox{GeV}$), and the CDF total cross section data, and
are also consistent with the value of $k=Z_{c\bar c}\cdot Br(X\to
J/\psi\pi^+\pi^-)$ constrained by the $B$-meson decay data. %It can also well
describe the behavior of the CDF $\psi(2S)$ data, which show a strong
%resemblance to that of the X(3872). For LHCb the predicted X(3872) total cross
section is larger than the data by a factor of 2, which is due to the problem
of the fixed-order NRQCD calculation that may not be applicable for the region
with small $p_T$ ($p_T\sim 5 ~\mbox{GeV}$) and large forward rapidity
$(2.5<y<4.5)$. In comparison, the prediction of molecule production mechanism
for $X(3872)$ is inconsistent with both $p_T$ distributions and total cross
sections of CMS and ATLAS, and the total cross section of CDF.


title:
Hyperfine interaction induced dephasing of coupled spin qubits in
  semiconductor double quantum dots

abstract:
  We investigate theoretically the hyperfine-induced dephasing of
two-electron-spin states in a double quantum dot with a finite singlet-triplet
splitting J. In particular, we derive an effective pure dephasing Hamiltonian,
which is valid when the hyperfine-induced mixing is suppressed due to the
relatively large J and the external magnetic field. Using both a quantum theory
based on resummation of ring diagrams and semiclassical methods, we identify
the dominant dephasing processes in regimes defined by values of the external
magnetic field, the singlet-triplet splitting, and inhomogeneity in the total
effective magnetic field. We address both free induction and Hahn echo decay of
superposition of singlet and unpolarized triplet states (both cases are
relevant for singlet-triplet qubits realized in double quantum dots). We also
study hyperfine-induced exchange gate errors for two single-spin qubits.
Results for III-V semiconductors as well as silicon-based quantum dots are
presented.


title: A Simplified Approach to General Scalar-Tensor Theories

abstract:
  The most general covariant action describing gravity coupled to a scalar
field with only second order equations of motion, Horndeski's theory (also
known as "Generalized Galileons"), provides an all-encompassing model in which
single scalar dark energy models may be constrained. However, the generality of
the model makes it cumbersome to manipulate. In this paper, we demonstrate that
when considering linear perturbations about a Friedmann-Robertson-Walker
background, the theory is completely specified by only six functions of time,
two of which are constrained by the background evolution. We utilise the ideas
of the Effective Field Theory of Inflation/Dark Energy to explicitly construct
these six functions of time in terms of the free functions appearing in
Horndeski's theory. These results are used to investigate the behavior of the
theory in the quasistatic approximation. We find that only four functions of
time are required to completely specify the linear behavior of the theory in
this limit, which can further be reduced if the background evolution is fixed.
This presents a significantly reduced parameter space from the original
presentation of Horndeski's theory, giving hope to the possibility of
constraining the parameter space. This work provides a cross-check for previous
work on linear perturbations in this theory, and also generalizes it to include
spatial curvature.


title: Observational Constraints of Modified Chaplygin Gas in RS II Brane

abstract:
  FRW universe in RS II braneworld model filled with a combination of dark
matter and dark energy in the form of modified Chaplygin gas (MCG) is
considered. It is known that the equation of state (EoS) for MCG is a
three-variable equation determined by $A$, $\alpha$ and $B$. The permitted
values of these parameters are determined by the recent astrophysical and
cosmological observational data. Here we present the Hubble parameter in terms
of the observable parameters $\Omega_{m0}$, $\Omega_{x0}$, $H_{0}$, redshift
$z$ and other parameters like $A$, $B$, $C$ and $\alpha$. From Stern data set
(12 points), we have obtained the bounds of the arbitrary parameters by
minimizing the $\chi^{2}$ test. The best-fit values of the parameters are
obtained by 66%, 90% and 99% confidence levels. Next due to joint analysis with
BAO and CMB observations, we have also obtained the bounds of the parameters
($B,C$) by fixing some other parameters $\alpha$ and $A$. The best fit value of
distance modulus $\mu(z)$ is obtained for the MCG model in RS II brane, and it
is concluded that our model is perfectly consistent with the union2 sample
data.


title: High sensitivity measurements of thermal properties of textile fabrics

abstract:
  A new testing apparatus is proposed to measure the thermal properties of
fabrics made from polymeric materials. The calibration of the apparatus and the
data acquisition procedure are considered in detail in order to measure thermal
conductivity, resistance, absorption and diffusivity constants of the tested
fabric samples. Differences between dry and wet fabrics have been carefully
detected and analyzed. We have developed a new measurement protocol, the
"ThermoTex" protocol, which agrees with the UNI EN 31092 standard and entails
an accurate quantification of the experimental errors according to a standard
statistical analysis, thus allowing a rigorous investigation of the physical
behavior of the phenomena involved. As a consequence, our machinery exhibits
great potentialities for optimizing the thermal comfort of fabrics, according
to the market demand, thanks to the possible development of a predictive
phenomenological theory of the effects involved.


title: Skewness and kurtosis unbiased by Gaussian uncertainties

abstract:
  Noise is an unavoidable part of most measurements which can hinder a correct
interpretation of the data. Uncertainties propagate in the data analysis and
can lead to biased results even in basic descriptive statistics such as the
central moments and cumulants. Expressions of noise-unbiased estimates of
central moments and cumulants up to the fourth order are presented under the
assumption of independent Gaussian uncertainties, for weighted and unweighted
statistics. These results are expected to be relevant for applications of the
skewness and kurtosis estimators such as outlier detections, normality tests
and in automated classification procedures. The comparison of estimators
corrected and not corrected for noise biases is illustrated with simulations as
a function of signal-to-noise ratio, employing different sample sizes and
weighting schemes.


title: MAGIICAT I. The MgII Absorber-Galaxy Catalog

abstract:
  We describe the MgII Absorber-Galaxy Catalog, MAGIICAT, a compilation of 182
spectroscopically identified intermediate redshift (0.07 < z < 1.1) galaxies
with measurements of MgII 2796, 2803 absorption from their circumgalactic
medium within projected distances of 200 kpc from background quasars. In this
work, we present "isolated" galaxies, which are defined as having no
spectroscopically identified galaxy within a projected distance of 100 kpc and
a line of sight velocity separation of 500 km/s. We standardized all galaxy
properties to the Lambda CDM cosmology and galaxy luminosities, absolute
magnitudes, and rest-frame colors to the B- and K-band on the AB system. We
present galaxy properties and rest-frame MgII equivalent width, Wr(2796),
versus galaxy redshift. The well-known anti-correlation between Wr(2796) and
quasar-galaxy impact parameter, D, is significant to the 8 sigma level. The
mean color of MAGIICAT galaxies is consistent with an Sbc galaxy for all
redshifts. We also present B- and K-band luminosity functions for different
Wr(2796) and redshift subsamples: "weak absorbing" [Wr(2796) < 0.3 Ang],
"strong absorbing" [Wr(2796) > 0.3 Ang], low redshift (z < zmed), and high
redshift (z > zmed), where zmed = 0.359 is the median galaxy redshift.
Rest-frame color B-K correlates with M_K at the 8 sigma level for the whole
sample but is driven by the strong absorbing, high redshift subsample (6
sigma). Using M_K as a proxy for stellar mass and examining the luminosity
functions, we infer that in lower stellar mass galaxies, MgII absorption is
preferentially detected in blue galaxies and the absorption is more likely to
be weak.


title: Are there tangled magnetic fields on HgMn stars?

abstract:
  Several recent spectrophotometric studies failed to detect significant global
magnetic fields in late-B HgMn chemically peculiar stars, but some
investigations have suggested the presence of strong unstructured or tangled
fields in these objects. We used detailed spectrum synthesis analysis to search
for evidence of tangled magnetic fields in high-quality observed spectra of 8
slowly rotating HgMn stars and one normal late-B star. We also evaluated recent
sporadic detections of weak longitudinal magnetic fields in HgMn stars based on
the moment technique. Our analysis of the Zeeman broadening of magnetically
sensitive spectral lines reveals no evidence of tangled magnetic fields in any
of the studied HgMn or normal stars. We infer upper limits of 200-700 G for the
mean magnetic field modulus -- much smaller than the field strengths implied by
studies based on differential magnetic line intensification and quadratic field
diagnostics. The new HARPSpol longitudinal field measurements for the extreme
HgMn star HD 65949 and the normal late-B star 21 Peg are consistent with zero
at a precision of 3-6 G. Re-analysis of our Stokes V spectra of the spotted
HgMn star HD 11753 shows that the recent moment technique measurements
retrieved from the same data are incompatible with the lack of circular
polarization signatures in the spectrum of this star. We conclude that there is
no evidence for substantial tangled magnetic fields on the surfaces of studied
HgMn stars. We cannot independently confirm the presence of very strong
quadratic or marginal longitudinal fields for these stars, so results from the
moment technique are likely to be spurious.


title:
Three-Dimensional Model of Cosmic-Ray Lepton Propagation Reproduces Data
  from the Alpha Magnetic Spectrometer on the International Space Station

abstract:
  We study the compatibility of Alpha Magnetic Spectrometer (AMS-02) data on
the cosmic-ray (CR) positron fraction with data on the CR electron and positron
spectra provided by PAMELA and Fermi LAT. We do that in terms of a novel
propagation model in which sources are distributed in spiral arm patterns in
agreement with astrophysical observations. While former interpretations assumed
an unrealistically steep injection spectrum for astrophysical background
electrons, the enhanced energy losses experienced by CR leptons due to the
larger average source distance from Earth allow us to reproduce the data with
harder injection spectra as expected in a shock acceleration scenario.
Moreover, we show that in this approach, and accounting for AMS-02 results, the
contribution of nearby accelerators to the fluxes at very high energy can be
significantly reduced, thus avoiding any tension with anisotropy upper limits.


title:
The Column Density Distribution and Continuum Opacity of the
  Intergalactic and Circumgalactic Medium at Redshift <z>=2.4

abstract:
  We present new high-precision measurements of the opacity of the
intergalactic and circumgalactic medium (IGM, CGM) at <z>=2.4. Using Voigt
profile fits to the full Lyman alpha and Lyman beta forests in 15
high-resolution high-S/N spectra of hyperluminous QSOs, we make the first
statistically robust measurement of the frequency of absorbers with HI column
densities 14 < log(NHI) < 17.2. We also present the first measurements of the
frequency distribution of HI absorbers in the volume surrounding high-z
galaxies (the CGM, 300 pkpc), finding that the incidence of absorbers in the
CGM is much higher than in the IGM. In agreement with Rudie et al. (2012), we
find that there are fractionally more high-NHI absorbers than low-NHI absorbers
in the CGM compared to the IGM, leading to a shallower power law fit to the CGM
frequency distribution. We use these new measurements to calculate the total
opacity of the IGM and CGM to hydrogen-ionizing photons, finding significantly
higher opacity than most previous studies, especially from absorbers with
log(NHI) < 17.2. Reproducing the opacity measured in our data as well as the
incidence of absorbers with log(NHI) > 17.2 requires a broken power law
parameterization of the frequency distribution with a break near log(NHI) ~ 15.
We compute new estimates of the mean free path (mfp) to hydrogen-ionizing
photons at z=2.4, finding mfp = 147 +- 15 Mpc when considering only IGM
opacity. If instead, we consider photons emanating from a high-z star-forming
galaxy and account for the local excess opacity due to the surrounding CGM of
the galaxy itself, the mean free path is reduced to mfp = 121 +- 15 Mpc. These
mfp measurements are smaller than recent estimates and should inform future
studies of the metagalactic UV background and of ionizing sources at z~2-3.


title:
Delayed outflows from black hole accretion tori following neutron star
  binary coalescence

abstract:
  Expulsion of neutron-rich matter following the merger of neutron star (NS)
binaries is crucial to the radioactively-powered electromagnetic counterparts
of these events and to their relevance as sources of r-process nucleosynthesis.
Here we explore the long-term (viscous) evolution of remnant black hole
accretion disks formed in such mergers by means of two-dimensional,
time-dependent hydrodynamical simulations. The evolution of the electron
fraction due to charged-current weak interactions is included, and neutrino
self-irradiation is modeled as a lightbulb that accounts for the disk geometry
and moderate optical depth effects. Over several viscous times (~1s), a
fraction ~10% of the initial disk mass is ejected as a moderately neutron-rich
wind (Y_e ~ 0.2) powered by viscous heating and nuclear recombination, with
neutrino self-irradiation playing a sub-dominant role. Although the properties
of the outflow vary in time and direction, their mean values in the
heavy-element production region are relatively robust to variations in the
initial conditions of the disk and the magnitude of its viscosity. The outflow
is sufficiently neutron-rich that most of the ejecta forms heavy r-process
elements with mass number A >130, thus representing a new astrophysical source
of r-process nucleosynthesis, distinct from that produced in the dynamical
ejecta. Due to its moderately high entropy, disk outflows contain a small
residual fraction ~1% of helium, which could produce a unique spectroscopic
signature.


title: RG Domain Walls and Hybrid Triangulations

abstract:
  This paper studies the interplay between the N=2 gauge theories in three and
four dimensions that have a geometric description in terms of twisted
compactification of the six-dimensional (2,0) SCFT. Our main goal is to
construct the three-dimensional domain walls associated to any
three-dimensional cobordism. We find that we can build a variety of 3d theories
that represent the local degrees of freedom at a given domain wall in various
4d duality frames, including both UV S-dual frames and IR Seiberg-Witten
electric-magnetic dual frames. We pay special attention to Janus domain walls,
defined by four-dimensional Lagrangians with position-dependent couplings. If
the couplings on either side of the wall are weak in different UV duality
frames, Janus domain walls reduce to S-duality walls, i.e. domain walls that
encode the properties of UV dualities. If the couplings on one side are weak in
the IR and on the other weak in the UV, Janus domain walls reduce to RG walls,
i.e. domain walls that encode the properties of RG flows. We derive the 3d
geometries associated to both types of domain wall, and test their properties
in simple examples, both through basic field-theoretic considerations and via
comparison with quantum Teichmuller theory. Our main mathematical tool is a
parametrization and quantization of framed flat SL(K) connections on these
geometries based on ideal triangulations.


title:
ALMA follows streaming of dense gas down to 40 pc from the supermassive
  black hole in NGC1097

abstract:
  We present a kinematic analysis of the dense molecular gas in the central 200
parsecs of the nearby galaxy NGC1097, based on Cycle 0 observations with the
Atacama Large Millimeter/sub-millimeter Array (ALMA). We use the HCN(4-3) line
to trace the densest interstellar molecular gas, and quantify its kinematics,
and estimate an inflow rate for the molecular gas. We find a striking
similarity between the ALMA kinematic data and the analytic spiral inflow model
that we have previously constructed based on ionized gas velocity fields on
larger scales. We are able to follow dense gas streaming down to 40 pc distance
from the supermassive black hole in this Seyfert 1 galaxy. In order to fulfill
marginal stability, we deduce that the dense gas is confined to a very thin
disc, and we derive a dense gas inflow rate of 0.09 Msun/yr at 40 pc radius.
Combined with previous values from the Ha and CO gas, we calculate a combined
molecular and ionized gas inflow rate of 0.2 Msun/yr at 40 pc distance from the
central supermassive black hole of NGC1097.


title:
The SLUGGS survey: Probing the supermassive black hole connection with
  bulges and haloes using red and blue globular cluster systems

abstract:
  Understanding whether the bulge or the halo provides the primary link to the
growth of supermassive black holes has strong implications for galaxy evolution
and supermassive black hole formation itself. In this paper, we approach this
issue by investigating extragalactic globular cluster (GC) systems, which can
be used to probe the physics of both the bulge and the halo of the host galaxy.
We study the relation between the supermassive black hole masses M_BH and the
globular cluster system velocity dispersions sigma_GC using an updated and
improved sample of 21 galaxies. We exploit the dichotomy of globular cluster
system colours, to test if the blue and red globular clusters correlate
differently with black hole mass. This may be expected if they trace the
potentially different formation history of the halo and of the bulge of the
host galaxy respectively. We find that M_BH correlates with the total GC system
velocity dispersion, although not as strongly as claimed by recent work of
Sadoun & Colin. We also examine the M_BH - sigma_GC relation for
barred/bar-less and core/non-core galaxies, finding no significant difference,
and for the first time we quantify the impact of radial gradients in the GC
system velocity dispersion profile on the M_BH - sigma_GC relation. We
additionally predict M_BH in 13 galaxies, including dwarf elliptical galaxies
and the cD galaxy NGC 3311. We conclude that our current results cannot
discriminate between the bulge/halo scenario. Although there is a hint that the
red GC velocity dispersion might correlate better with M_BH than the blue GC
velocity dispersion, the number statistics are still too low to be certain.


title:
Two-dimensional crystal melting and D4-D2-D0 on toric Calabi-Yau
  singularities

abstract:
  We construct a two-dimensional crystal melting model which reproduces the BPS
index of D2-D0 states bound to a non-compact D4-brane on an arbitrary toric
Calabi-Yau singularity. The crystalline structure depends on the toric divisor
wrapped by the D4-brane. The molten crystals are in one-to-one correspondence
with the torus fixed points of the moduli space of the quiver gauge theory on
D-branes. The F- and D-term constraints of the gauge theory are regarded as a
generalization of the ADHM constraints on instantons. We also show in several
examples that our model is consistent with the wall-crossing formula for the
BPS index.


title:
Massive spin-2 fields on black hole spacetimes: Instability of the
  Schwarzschild and Kerr solutions and bounds on the graviton mass

abstract:
  Massive bosonic fields of arbitrary spin are predicted by general extensions
of the Standard Model. It has been recently shown that there exists a family of
bimetric theories of gravity - including massive gravity - which are free of
Boulware-Deser ghosts at the nonlinear level. This opens up the possibility to
describe consistently the dynamics of massive spin-2 particles in a
gravitational field. Within this context, we develop the study of massive
spin-2 fluctuations - including massive gravitons - around Schwarzschild and
slowly-rotating Kerr black holes. Our work has two important outcomes. First,
we show that the Schwarzschild geometry is linearly unstable for small tensor
masses, against a spherically symmetric mode. Second, we provide solid evidence
that the Kerr geometry is also generically unstable, both against the spherical
mode and against long-lived superradiant modes. In the absence of nonlinear
effects, the observation of spinning black holes bounds the graviton mass to be
smaller than 5x10^{-23} eV.


title:
Exoplanet Characterization by Proxy: a Transiting 2.15 R_Earth Planet
  Near the Habitable Zone of the Late K dwarf Kepler-61

abstract:
  We present the validation and characterization of Kepler-61b: a 2.15 R_Earth
planet orbiting near the inner edge of the habitable zone of a low-mass star.
Our characterization of the host star Kepler-61 is based upon a comparison with
the set of spectroscopically similar stars with directly-measured radii and
temperatures. We apply a stellar prior drawn from the weighted mean of these
properties, in tandem with the Kepler photometry, to infer a planetary radius
for Kepler-61b of 2.15+/-0.13 R_Earth and an equilibrium temperature of
273+/-13 K (given its period of 59.87756+/-0.00020 days and assuming a
planetary albedo of 0.3). The technique of leveraging the physical properties
of nearby "proxy" stars allows for an independent check on stellar
characterization via the traditional measurements with stellar spectra and
evolutionary models. In this case, such a check had implications for the
putative habitability of Kepler-61b: the planet is 10% warmer and larger than
inferred from K-band spectral characterization. From the Kepler photometry, we
estimate a stellar rotation period of 36 days, which implies a stellar age of
>1 Gyr. We summarize the evidence for the planetary nature of the Kepler-61
transit signal, which we conclude is 30,000 times more likely to be due to a
planet than a blend scenario. Finally, we discuss possible compositions for
Kepler-61b with a comparison to theoretical models as well as to known
exoplanets with similar radii and dynamically measured masses.


title: Higgs couplings to fermions: 2HDM with MFV

abstract:
  We clarify several subtleties concerning the implementation of minimal flavor
violation (MFV) in two Higgs doublet models. We derive all the exact and
approximate predictions of MFV for the neutral scalar (h,H,A) Yukawa couplings
to fermions. We point out several possible tests of this framework at the LHC.


title: An Acataleptic Universe

abstract:
  John Wheeler advocated the principle that information is the foundation of
physics and asked us to reformulate physics in terms of bits. The goal is to
consider what we know already and work out a new mathematical theory in which
space, time and matter are secondary. An application of the converse of
Noether's second theorem to the holographic principle implies that physics must
have an underlying hidden symmetry with degrees of symmetry that match physical
degrees of freedom in order to account for the huge redundancy of information
in the interior of a black-hole. I have been working on a theory that builds
infinite dimensional symmetries using layers of quantisation from information
as suggested by Wheeler's contemporary Carl von Weizs\"acker. Necklace Lie
algebras are the mathematical objects and iterated integration can be used to
show how a continuum background can emerge from their structure. The logic
suggests the conclusion that wheeler was right when he proclaimed "It from Bit"


title: Holographic d-wave superconductors

abstract:
  We construct top down models for holographic d-wave superfluids in which the
order parameter is a charged spin two field in the bulk. Close to the
transition temperature the condensed phase can be captured by a charged spin
two field in an R-charged black hole background (downstairs picture) or
equivalently by specific graviton perturbations of a spinning black brane
(upstairs picture). We analyse the necessary conditions on the mass and the
charge of the spin two field for a condensed phase to exist and we discuss the
competition of the d-wave phase with other phases such as s-wave superfluids.


title: NOON states in cavities

abstract:
  We show how NOON states may be generated entangling two cavities by passing
atoms through them. The atoms interact with each cavity via two-photon resonant
transitions. We take advantage of the fact that depending on the state the atom
enter (excite or ground), it leaves or takes two photons per interaction and
leaves the cavities in a pure state.


title:
A State Transition of the Luminous X-ray Binary in the Low-Metallicity
  Blue Compact Dwarf Galaxy I Zw 18

abstract:
  We present a measurement of the X-ray spectrum of the luminous X-ray binary
in I Zw 18, the blue compact dwarf galaxy with the lowest known metallicity. We
find the highest flux yet observed, corresponding to an intrinsic luminosity
near 1E40 erg/s establishing it as an ultraluminous X-ray source (ULX). The
energy spectrum is dominated by disk emission with a weak or absent Compton
component and there is no significant timing noise; both are indicative of the
thermal state of stellar-mass black hole X-ray binaries and inconsistent with
the Compton-dominated state typical of most ULX spectra. A previous measurement
of the X-ray spectrum shows a harder spectrum that is well described by a
powerlaw. Thus, the binary appears to exhibit spectral states similar to those
observed from stellar-mass black hole binaries. If the hard state occurs in the
range of luminosities found for the hard state in stellar-mass black hole
binaries, then the black hole mass must be at least 85 solar masses. Spectral
fitting of the thermal state shows that disk luminosities for which thin disk
models are expected to be valid are produced only for relatively high disk
inclinations, >= 60 degrees, and rapid black hole spins. We find a_* > 0.98 and
M > 154 solar masses for a disk inclination of 60 degrees. Higher inclinations
produce higher masses and somewhat lower spins.


title: Electroweak versus high scale finetuning in the 19-parameter SUGRA model

abstract:
  Recently, two measures of electroweak finetuning (EWFT) have been introduced
for SUSY models: \Delta_{EW} compares the Z mass to each separate weak scale
contribution to m_Z while \Delta_{HS} compares the Z mass to high scale input
parameters and their consequent renormalizaton group evolution (1/\Delta is the
% of fine tuning). While the paradigm mSUGRA/CMSSM model has been shown to be
highly finetuned under both parameters (\Delta_{EW}> 10^2 and \Delta_{HS}>
10^3), the two-parameter non-universal Higgs model (NUHM2) in the context of
radiatively-driven natural SUSY (RNS) enjoys \Delta_{EW} as low as 10, while
\Delta_{HS} remains > 10^3. We investigate finetuning in the 19-free-parameter
SUGRA model (SUGRA19). We find that with 19 free parameters, the lowest
\Delta_{EW} points are comparable to what can be achieved in NUHM2 with just 6
free parameters. However, in SUGRA19, \Delta_{HS} can now also reach as low as
5-10. The conditions which lead to low \Delta_{HS} include m_{H_u} m_Z at the
high scale, with non-universal gaugino masses M_{1,2}>> M_3 also at m_{GUT}.
The low \Delta_{HS} models are severely constrained by b\to s\gamma branching
fraction. In both cases of low \Delta_{EW} and \Delta_{HS}, the superpotential
\mu parameter should be \sim 100-300 GeV. While SUSY models with low EWFT may
or may not be discoverable at LHC, the predicted light higgsinos must show up
at a linear e^+e^- collider with \sqrt{s}> 2|\mu |.


title: A Zig-Zag Index

abstract:
  We study the large N superconformal index of quiver gauge theories describing
the worldvolume of D3 branes probing toric Calabi Yau singularities. The index
has been previously noticed to factorize over the set of the extremal BPS
mesonic operators of the gauge theory. We review this factorization and
reformulate it in terms of zig-zag paths in the dimer model associated to the
quiver. By using this reformulation, we argue that the factorization is valid
not only for the exact R charge but for every set of R_{trial} respecting the
marginality constraints. Moreover, we show the factorization of the index also
in theories with orbifold singularities, previously not investigated. We
conclude by providing an expression for the index in terms of the toric data of
the dual geometry.


title:
Separating regular languages by piecewise testable and unambiguous
  languages

abstract:
  Separation is a classical problem asking whether, given two sets belonging to
some class, it is possible to separate them by a set from a smaller class. We
discuss the separation problem for regular languages. We give a Ptime algorithm
to check whether two given regular languages are separable by a piecewise
testable language, that is, whether a $B{\Sigma}1(<)$ sentence can witness that
the languages are disjoint. The proof refines an algebraic argument from
Almeida and the third author. When separation is possible, we also express a
separator by saturating one of the original languages by a suitable congruence.
Following the same line, we show that one can as well decide whether two
regular languages can be separated by an unambiguous language, albeit with a
higher complexity.


title: Josephson vortex lattice in layered superconductors

abstract:
  Many superconducting materials are composed of weakly coupled conducting
layers. Such a layered structure has a very strong influence on the properties
of vortex matter in a magnetic field. This review focuses on the properties of
the Josephson vortex lattice generated by the magnetic field applied in the
layers direction. The theoretical description is based on the Lawrence-Doniach
model in the London limit which takes into account only the phase degree of
freedom of the superconducting order parameter. In spite of its simplicity,
this model leads to an amazingly rich set of phenomena. We review in details
the structure of an isolated vortex line as well as various properties of the
vortex lattice, both in dilute and dense limits. In particular, we present an
extensive consideration on the influence of the layered structure and thermal
fluctuations on the selection of lattice configurations at different magnetic
fields.


title: Networks in Cognitive Science

abstract:
  Networks of interconnected nodes have long played a key role in Cognitive
Science, from artificial neural net- works to spreading activation models of
semantic mem- ory. Recently, however, a new Network Science has been developed,
providing insights into the emergence of global, system-scale properties in
contexts as diverse as the Internet, metabolic reactions, and collaborations
among scientists. Today, the inclusion of network theory into Cognitive
Sciences, and the expansion of complex- systems science, promises to
significantly change the way in which the organization and dynamics of
cognitive and behavioral processes are understood. In this paper, we review
recent contributions of network theory at different levels and domains within
the Cognitive Sciences.


title: Frame independent cosmological perturbations

abstract:
  We compute the third order gauge invariant action for scalar-graviton
interactions in the Jordan frame. We demonstrate that the gauge invariant
action for scalar and tensor perturbations on one physical hypersurface only
differs from that on another physical hypersurface via terms proportional to
the equation of motion and boundary terms, such that the evolution of
non-Gaussianity may be called unique. Moreover, we demonstrate that the gauge
invariant curvature perturbation and graviton on uniform field hypersurfaces in
the Jordan frame are equal to their counterparts in the Einstein frame. These
frame independent perturbations are therefore particularly useful in relating
results in different frames at the perturbative level. On the other hand, the
field perturbation and graviton on uniform curvature hypersurfaces in the
Jordan and Einstein frame are non-linearly related, as are their corresponding
actions and $n$-point functions.


title: Core-scale solute transport model selection using Monte Carlo analysis

abstract:
  Model applicability to core-scale solute transport is evaluated using
breakthrough data from column experiments conducted with conservative tracers
tritium (H-3) and sodium-22, and the retarding solute uranium-232. The three
models considered are single-porosity, double-porosity with single-rate
mobile-immobile mass-exchange, and the multirate model, which is a
deterministic model that admits the statistics of a random mobile-immobile
mass-exchange rate coefficient. The experiments were conducted on intact
Culebra Dolomite core samples. Previously, data were analyzed using single- and
double-porosity models although the Culebra Dolomite is known to possess
multiple types and scales of porosity, and to exhibit multirate
mobile-immobile-domain mass transfer characteristics at field scale. The data
are reanalyzed here and null-space Monte Carlo analysis is used to facilitate
objective model selection. Prediction (or residual) bias is adopted as a
measure of the model structural error. The analysis clearly shows single- and
double-porosity models are structurally deficient, yielding late-time residual
bias that grows with time. On the other hand, the multirate model yields
unbiased predictions consistent with the late-time -5/2 slope diagnostic of
multirate mass transfer. The analysis indicates the multirate model is better
suited to describing core-scale solute breakthrough in the Culebra Dolomite
than the other two models.


title: The Magnetic Field Morphology of the Class 0 Protostar L1157-mm

abstract:
  We present the first detection of polarization around the Class 0 low-mass
protostar L1157-mm at two different wavelengths. We show polarimetric maps at
large scales (10" resolution at 350 um) from the SHARC-II Polarimeter and at
smaller scales (1.2"-4.5" at 1.3 mm) from the Combined Array for Research in
Millimeter-wave Astronomy (CARMA). The observations are consistent with each
other and show inferred magnetic field lines aligned with the outflow. The
CARMA observations suggest a full hourglass magnetic field morphology centered
about the core; this is only the second well-defined hourglass detected around
a low-mass protostar to date. We apply two different methods to CARMA
polarimetric observations to estimate the plane-of-sky magnetic field
magnitude, finding values of 1.4 and 3.4 mG.


title:
Algebraic Algorithms for b-Matching, Shortest Undirected Paths, and
  f-Factors

abstract:
  Let G=(V,E) be a graph with f:V\to Z_+ a function assigning degree bounds to
vertices. We present the first efficient algebraic algorithm to find an
f-factor. The time is \tilde{O}(f(V)^{\omega}). More generally for graphs with
integral edge weights of maximum absolute value W we find a maximum weight
f-factor in time \tilde{O}(Wf(V)^{\omega}). (The algorithms are randomized,
correct with high probability and Las Vegas; the time bound is worst-case.) We
also present three specializations of these algorithms: For maximum weight
perfect f-matching the algorithm is considerably simpler (and almost identical
to its special case of ordinary weighted matching). For the single-source
shortest-path problem in undirected graphs with conservative edge weights, we
present a generalization of the shortest-path tree, and we compute it in
\tilde{O(Wn^{\omega}) time. For bipartite graphs, we improve the known
complexity bounds for vertex capacitated max-flow and min-cost max-flow on a
subclass of graphs.


title:
Tabulated equation of state for supernova matter including full nuclear
  ensemble

abstract:
  This is an introduction to the tabulated data base of stellar matter
properties calculated within the framework of the Statistical Model for
Supernova Matter (SMSM). The tables present thermodynamical characteristics and
nuclear abundances for 31 values of baryon density (10$^{-8}<\rho/\rho_0<$0.32,
$\rho_0$=0.15 fm$^{-3}$ is the normal nuclear matter density), 35 values of
temperature ($0.2<T<25$ MeV) and 28 values of electron-to-baryon ratio
($0.02<Y_e<0.56$). The properties of stellar matter in $\beta$-equilibrium are
also considered. The main ingredients of the SMSM are briefly outlined, and the
data structure and content of the tables are explained.


title:
Interdisciplinarity and research on local issues: evidence from a
  developing country

abstract:
  This paper explores the relationship between interdisciplinarity and research
pertaining to local issues. Using Colombian publications from 1991 until 2011
in the Web of Science, we investigate the relationship between the degree of
interdisciplinarity and the local orientation of the articles. We find that a
higher degree of interdisciplinarity in a publication is associated with a
greater emphasis on Colombian issues. In particular, our results suggest that
research that combines cognitively disparate disciplines, what we refer to as
distal interdisciplinarity, tends to be associated with more local focus of
research. We discuss the implications of these results in the context of
policies aiming to foster the local socio-economic impact of research in
developing countries.


title: A Combinatorial Approach to Quantum Error Correcting Codes

abstract:
  Motivated from the theory of quantum error correcting codes, we investigate a
combinatorial problem that involves a symmetric $n$-vertices colourable graph
and a group of operations (colouring rules) on the graph: find the minimum
sequence of operations that maps between two given graph colourings. We provide
an explicit algorithm for computing the solution of our problem, which in turn
is directly related to computing the distance (performance) of an underlying
quantum error correcting code. Computing the distance of a quantum code is a
highly non-trivial problem and our method may be of use in the construction of
better codes.


title:
Central Limit Theorem for Linear Statistics of Eigenvalues of Band
  Random Matrices

abstract:
  We prove the Central Limit Theorem for linear statistics of the eigenvalues
of band random matrices provided $\sqrt{n} \ll b_n \ll n$ and test functions
are sufficiently smooth.


title: Explicit secular equation for Scholte waves over a monoclinic crystal

abstract:
  The aim of this Letter is to derive explicitly the secular equation for
Scholte waves at the interface between a fluid and an anisotropic crystal cut
along a plane containing the normal to a single symmetry plane, that is
containing only one crystallographic axis.


title: Wald tests of singular hypotheses

abstract:
  Motivated by the problem of testing tetrad constraints in factor analysis, we
study the large-sample distribution of Wald statistics at parameter points at
which the gradient of the tested constraint vanishes. When based on an
asymptotically normal estimator, the Wald statistic converges to a rational
function of a normal random vector. The rational function is determined by a
homogeneous polynomial and a covariance matrix. For quadratic forms and
bivariate monomials of arbitrary degree, we show unexpected relationships to
chi-square distributions that explain conservative behavior of certain Wald
tests. For general monomials, we offer a conjecture according to which the
reciprocal of a certain quadratic form in the reciprocals of dependent normal
random variables is chi-square distributed.


title:
Hubble Tarantula Treasury Project: Unraveling Tarantula's Web. I.
  Observational overview and first results

abstract:
  The Hubble Tarantula Treasury Project (HTTP) is an ongoing panchromatic
imaging survey of stellar populations in the Tarantula Nebula in the Large
Magellanic Cloud that reaches into the sub-solar mass regime (< 0.5 Mo). HTTP
utilizes the capability of HST to operate the Advanced Camera for Surveys (ACS)
and the Wide Field Camera 3 (WFC3) in parallel to study this remarkable region
in the near-ultraviolet, optical, and near-infrared spectral regions, including
narrow band H$\alpha$ images. The combination of all these bands provides a
unique multi-band view. The resulting maps of the stellar content of the
Tarantula Nebula within its main body provide the basis for investigations of
star formation in an environment resembling the extreme conditions found in
starburst galaxies and in the early Universe. Access to detailed properties of
individual stars allows us to begin to reconstruct the evolution of the stellar
skeleton of the Tarantula Nebula over space and time with parcsec-scale
resolution. In this first paper we describe the observing strategy, the
photometric techniques, and the upcoming data products from this survey and
present preliminary results obtained from the analysis of the initial set of
near-infrared observations.