title:
A 10B-based neutron detector with stacked Multiwire Proportional
  Counters and macrostructured cathodes

abstract:
  We present the results of the measurements of the detection efficiency for a
4.7 \r{A} neutron beam incident upon a detector incorporating a stack of up to
five MultiWire Proportional Counters (MWPC) with Boron-coated cathodes. The
cathodes were made of Aluminum and had a surface exhibiting millimeter-deep
V-shaped grooves of 45{\deg}, upon which the thin Boron film was deposited by
DC magnetron sputtering. The incident neutrons interacting with the converter
layer deposited on the sidewalls of the grooves have a higher capture
probability, owing to the larger effective absorption film thickness. This
leads to a higher overall detection efficiency for the grooved cathode when
compared to a cathode with a flat surface. Both the experimental results and
the predictions of the GEANT4 model suggests that a 5-counter detector stack
with coated grooved cathodes has the same efficiency as a 7-counter stack with
flat cathodes. The reduction in the number of counters in the stack without
altering the detection efficiency will prove highly beneficial for large-area
position-sensitive detectors for neutron scattering applications, for which the
cost-effective manufacturing of the detector and associated readout electronics
is an important objective. The proposed detector concept could be a
technological option for one of the new chopper spectrometers and other
instruments planned to be built at the future European Spallation Source in
Sweden. These results with macrostructured cathodes generally apply not just to
MWPCs but to other gaseous detectors as well.


title: Dynamics of the solar atmosphere above a pore with a light bridge

abstract:
  Context: Solar pores are small sunspots lacking a penumbra that have a
prevailing vertical magnetic field component. They can include light bridges at
places with locally reduced magnetic field. Like sunspots, they exhibit a wide
range of oscillatory phenomena.
  Aims: A large isolated pore with a light bridge (NOAA 11005) is studied to
obtain characteristics of a chromospheric filamentary structure around the
pore, to analyse oscillations and waves in and around the pore, and to
understand the structure and brightness of the light bridge.
  Methods: Spectral imaging observations in the line Ca II 854.2 nm and
complementary spectropolarimetry in Fe I lines, obtained with the DST/IBIS
spectrometer and HINODE/SOT spectropolarimeter, were used to measure
photospheric and chromospheric velocity fields, oscillations, waves, the
magnetic field in the photosphere, and acoustic energy flux and radiative
losses in the chromosphere.
  Results: The chromospheric filamentary structure around the pore has all
important characteristics of a superpenumbra: it shows an inverse Evershed
effect and running waves, and has a similar morphology and oscillation
character. The granular structure of the light bridge in the upper photosphere
can be explained by radiative heating. Acoustic waves leaking up from the
photosphere along the inclined magnetic field in the light bridge transfer
enough energy flux to balance the total radiative losses of the light-bridge
chromosphere.
  Conclusions: The presence of a penumbra is not a necessary condition for the
formation of a superpenumbra. The light bridge is heated by radiation in the
photosphere and by acoustic waves in the chromosphere.


title:
Towards the Identification of New Physics through Correlations between
  Flavour Observables

abstract:
  We emphasize the power of correlations between flavour observables in the
search for New Physics and identify a number of correlations that could allow
to discover New Physics even if it would appear at the level of 20% of the
Standard Model contributions. After presenting the simplest correlations in
CMFV and U(2)^3 models we address the recent data on B_{s,d}->mu^+ mu^- and the
anomalies in B_d -> K^* mu^+ mu^- in the context of Z'-models and SM Z, both
with flavour violating neutral couplings. A strategy consisting of twelve steps
which concentrate on theoretically clean observables, to be measured in this
decade, could one day allow us to reach the Zeptouniverse. The related DNA
charts based on the correlations between enhancements and supressions of
various observables in a given New Physics scenario relative to the Standard
Model predictions allow a transparent distinction between various extensions of
this model. The present text is the extended version of the talk to be
published in the proceedings of this symposium.


title: Astrochemistry: Synthesis and Modelling

abstract:
  We discuss models that astrochemists have developed to study the chemical
composition of the interstellar medium. These models aim at computing the
evolution of the chemical composition of a mixture of gas and dust under as-
trophysical conditions. These conditions, as well as the geometry and the
physical dynamics, have to be adapted to the objects being studied because
different classes of objects have very different characteristics (temperatures,
densities, UV radia- tion fields, geometry, history etc); e.g., proto-planetary
disks do not have the same characteristics as protostellar envelopes. Chemical
models are being improved continually thanks to comparisons with observations
but also thanks to laboratory and theoretical work in which the individual
processes are studied.


title:
Survey on the role of accelerator modes for anomalous diffusion: The
  case of the standard map

abstract:
  We perform an extensive and detailed analysis of the generalized diffusion
processes in deterministic area preserving maps with noncompact phase space,
exemplified by the standard map, with the special emphasis on understanding the
anomalous diffusion arising due to the accelerator modes. The accelerator modes
and their immediate neighborhood undergo ballistic transport in phase space,
and also the greater vicinity of them is still much affected ("dragged") by
them, giving rise to the non-Gaussian (accelerated) diffusion. The systematic
approach rests upon the following applications: the GALI method to detect the
regular and chaotic regions and thus to describe in detail the structure of the
phase space, the description of the momentum distribution in terms of the
L\'evy stable distributions, the numerical calculation of the diffusion
exponent and of the corresponding diffusion constant. We use this approach to
analyze in detail and systematically the standard map at all values of the kick
parameter $K$, up to $K=70$. All complex features of the anomalous diffusion
are well understood in terms of the role of the accelerator modes, mainly of
period 1 at large $K\ge 2\pi$, but also of higher periods (2,3,4,...) at
smaller values of $K\le 2\pi$.


title: Deformations of the discrete Heisenberg group

abstract:
  We study deformations of the discrete Heisenberg group acting properly
discontinuously on the Heisenberg group from the left and right and obtain a
complete description of the deformation space.


title:
Condensation phenomena in fat-tailed distributions: a characterization
  by means of an order parameter

abstract:
  Condensation phenomena are ubiquitous in nature and are found in condensed
matter, disordered systems, networks, finance, etc. In the present work we
investigate one of the best frameworks in which condensation phenomena take
place, namely, the sum of independent and fat-tailed distributed random
variables. For large deviations of the sum, this system undergoes a phase
transition and shifts from a democratic phase to a condensed phase, where a
single variable (the condensate) carries a finite fraction of the sum. This
phenomenon yields the failure of the standard results of the Large Deviation
Theory. In this work we exploit the Density Functional Method to overcome the
limitation of the Large Deviation Theory and characterize the condensation
transition in terms of an order parameter, i.e. the Inverse Participation Ratio
(IPR). This procedure leads us to investigate the system in the large-deviation
regime where both the sum and the IPR are constrained, observing new phase
transitions. As a sample application, the case of condensation phenomena in
financial time-series is briefly discussed.


title: Maximizing torsional rigidity on Riemannian manifolds

abstract:
  Let $\,(M,g)\,$ be a $n$-dimensional Riemannian manifold and $\,\Omega\,$ be
any compact connected domain in $\,M$. We study the problem of finding the {\em
maxima} of the functional $\, {\mathcal E} (\Omega)\,$ (known as {\em torsional
rigidity} associated to $\Omega$) among all domains of prescribed volume $v$.
Our results show that for a given Riemannian manifold which is strictly
isoperimetric at one of its points the maximum of such functional is realized
by the geodesic ball centered at this point. More generally, we prove estimates
for the functional $\, {\mathcal E} (\Omega)\,$ by comparison with symmetrized
domains. We also investigate on finding sharp upper bounds for the functional
$\, {\mathcal E} (\Omega)\,$, under certain conditions on the geometry of
$\,(M,g)\,$ and of $\Omega$. Finally we find an universal upper bound for $\,
{\mathcal E} (\Omega)\,$ in terms of the isoperimetric Cheeger constant.


title: Perfect screening of the inter-polaronic interaction

abstract:
  We consider heavy particles immersed in a Fermi sea of light fermions, and
study the interaction between the heavy particles induced by the surrounding
light fermions. With the Born-Oppenheimer method, we analytically show that the
induced interaction between N heavy particles vanishes for any N in the limit
of high light-fermion density. The induced interaction vanishes even in the
unitarity regime. This suggests that the formation of N-body bound states
associated with the Efimov effect is suppressed in the presence of the dense
Fermi sea. We ascribe the vanishing induced interaction to the screening effect
in the neutral Fermi system.


title:
Modelling the burden caused by gene expression: an in silico
  investigation into the interactions between synthetic gene circuits and their
  chassis cell

abstract:
  In this paper we motivate and develop a model of gene expression for the
purpose of studying the interaction between synthetic gene circuits and the
chassis cell within which they are in- serted. This model focuses on the
translational aspect of gene expression as this is where the literature
suggests the crucial interaction between gene expression and shared resources
lies.


title:
A kinematic study and membership analysis of the Lupus star-forming
  region

abstract:
  This paper is dedicated to investigating the kinematic properties of the
Lupus moving group of young stars with the primary objective of deriving
individual parallaxes for each group member. We identify those stars in the
Lupus star-forming region that define the comoving association of young stars
by utilizing our new and improved convergent point search method that allows us
to derive the precise position of the convergent point of the comoving
association from the stars' proper motions. We used published proper motion
catalogs and searched the literature for radial velocities, which are needed to
compute individual parallaxes. We supplemented the radial velocity data with
new measurements from spectroscopic observations performed with the FEROS
spectrograph mounted on the MPG/ESO 2.2m telescope at La Silla. We identify a
comoving group with 109 pre-main sequence stars and candidates that define the
kinematic properties of the Lupus low-mass star-forming region. We derive
individual parallaxes for stars with known radial velocity and tentative
parallaxes for the remaining group members by assuming that all stars share the
same space motion. The convergent point method, combined with the k-NN
algorithm, makes it possible to distinguish the Lupus and Upper Centaurus Lupus
stars from the adjacent Scorpius-Centaurus association. We find significant
depth effects in this region and show that the classical T Tauri stars, located
in the close vicinity of the Lupus molecular clouds, form a background
population, while the weak-emission line T Tauri stars are dispersed not only
in angular extent but also in depth. The newly derived individual parallaxes
will be used in a forthcoming paper to refine the masses and ages of Lupus T
Tauri stars, with the aim of better constraining the lifetimes of their
circumstellar, protoplanetary disks.


title: Semigroup Conjectures for Central Semidirect Product of R^n with R^m

abstract:
  In this paper we prove two new results about closed semigroups in the family
of solvable groups H_{mn} that are semidirect products of R^m and R^n, and for
which the structure homomorphism maps nontrivially into the center of Aut(R^n).
The first result states that the closure of a semigroup generated by a set in
H_{mn} that is not included in a maximal semigroup with nonempty interior is
actually a group. The second result states that among the subsets of H_{mn}
that are not included in a maximal proper semigroup, those that generate H_{mn}
as a closed semigroup are dense. Results of this nature were obtained before
only for extensions of nilpotent groups. Results of this nature were obtained
before only for abelian and nilpotent Lie groups and their compact extensions.
As an application of the technique developed in the paper, we find the minimal
number of generators as a closed group and as a closed semigroup of H_{mn}.


title:
On the Mellin transforms of the perpetuity and the remainder variables
  associated to a subordinator

abstract:
  Results about the laws of the perpetuity and remainder variables associated
to a subordinator are presented, with particular emphasis on their Mellin
transforms, and multiplicative infinite divisibility property. Previous results
by Bertoin-Yor (Electron. Commun. Probab. 6 (2001) 95-106) are incorporated in
our discussion; important examples when the subordinator is the inverse local
time of a diffusion are exhibited. Results of Urbanik (Probab. Math. Statist.
15 (1995) 493-513) are also discussed in detail; they appear to be too little
known, despite the fact that quite a few of them have priority upon other works
in this area.


title: Endpoint Symmetries of Helicity Amplitudes

abstract:
  We investigate helicity amplitudes (HAs) of $A \to B C$-type decays for
arbitrary spin towards the kinematic endpoint. We show that they are
proportional to product of Clebsch-Gordan coefficients (CGC) and the velocity
to some positive power. The latter can be zero in which case the HA is
non-vanishing at the endpoint. In essence the spatial rotational symmetry,
broken by the relative spatial momenta of the particles, is restored at the
kinematic endpoint. Therefore SO(3) and SU(2), for bosons and fermion in the
decay, act like a global internal symmetry groups. Some of our results can be
understood in terms of the Wigner- Eckart theorem. The findings are useful for
i) checking theoretical computations and ii) the case where there is a sequence
of decays, say $B \to B_1B_2$ with the pair $(B_1B_2)$ not interacting
(significantly) with the $C$-particle. An example is $H \to Z Z^* \to 4\ell$
where our findings might be of use for experimentally determining the Higgs
quantum numbers. Angular observables, which are essentially ratios of HAs, are
given by ratios of CGC at the endpoint. We briefly discuss power corrections in
the velocity to the leading order.


title: Near Optimal Line Segment Weak Visibility Queries in Simple Polygons

abstract:
  This paper considers the problem of computing the weak visibility polygon
(WVP) of any query line segment pq (or WVP(pq)) inside a given simple polygon
P. We present an algorithm that preprocesses P and creates a data structure
from which WVP(pq) is efficiently reported in an output sensitive manner.
  Our algorithm needs O(n^2 log n) time and O(n^2) space in the preprocessing
phase to report WVP(pq) of any query line segment pq in time O(log^2 n +
|WVP(pq)|). We improve the preprocessing time and space of current results for
this problem at the expense of more query time.


title: On statistics, computation and scalability

abstract:
  How should statistical procedures be designed so as to be scalable
computationally to the massive datasets that are increasingly the norm? When
coupled with the requirement that an answer to an inferential question be
delivered within a certain time budget, this question has significant
repercussions for the field of statistics. With the goal of identifying
"time-data tradeoffs," we investigate some of the statistical consequences of
computational perspectives on scability, in particular divide-and-conquer
methodology and hierarchies of convex relaxations.


title: Control of atomic transport using autoresonance

abstract:
  Dynamics of an atomic wavepacket in an optical superlattice is considered. We
propose a simple scheme of wavepacket localization near the minima of the
optical potential. In our approach, a wavelike perturbation caused by an
additional lattice induces classical resonance which traps an atomic cloud.
Adiabatic phase modulation of the perturbation slowly shifts resonance zone in
phase space to the range of lower energies, retaining trapped atoms inside.
This phenomenon is a kind of autoresonance. Quantum computations agree well
with classical modelling.


title: New developments in FeynRules

abstract:
  The program FeynRules is a Mathematica package developed to facilitate the
implementation of new physics theories into high-energy physics tools. Starting
from a minimal set of information such as the model gauge symmetries, its
particle content, parameters and Lagrangian, FeynRules provides all necessary
routines to extract automatically from the Lagrangian (that can also be
computed semi-automatically for supersymmetric theories) the associated Feynman
rules. These can be further exported to several Monte Carlo event generators
through dedicated interfaces, as well as translated into a Python library,
under the so-called UFO model format, agnostic of the model complexity,
especially in terms of Lorentz and/or color structures appearing in the
vertices or of number of external legs. In this work, we briefly report on the
most recent new features that have been added to FeynRules, including full
support for spin-3/2 fermions, a new module allowing for the automated
diagonalization of the particle spectrum and a new set of routines dedicated to
decay width calculations.


title: Particle filters

abstract:
  This is a short review of Monte Carlo methods for approximating filter
distributions in state space models. The basic algorithm and different
strategies to reduce imbalance of the weights are discussed. Finally, methods
for more difficult problems like smoothing and parameter estimation and
applications outside the state space model context are presented.


title: General relativistic hydrodynamics in curvilinear coordinates

abstract:
  In this paper we report on what we believe is the first successful
implementation of relativistic hydrodynamics, coupled to dynamical spacetimes,
in spherical polar coordinates without symmetry assumptions. We employ a
high-resolution shock-capturing scheme, which requires that the equations be
cast in flux-conservative form. One example of such a form is the :Valencia"
formulation, which has been adopted in numerous applications, in particular in
Cartesian coordinates. Here we generalize this formulation to allow for a
reference-metric approach, which provides a natural framework for calculations
in curvilinear coordinates. In spherical polar coordinates, for example, it
allows for an analytical treatment of the singular r and sin(\theta) terms that
appear in the equations. We experiment with different versions of our
generalized Valencia formulation in numerical implementations of relativistic
hydrodynamics for both fixed and dynamical spacetimes. We consider a number of
different tests -- non-rotating and rotating relativistic stars, as well as
gravitational collapse to a black hole -- to demonstrate that our formulation
provides a promising approach to performing fully relativistic astrophysics
simulations in spherical polar coordinates.


title:
Asymptotic analysis of the lattice Boltzmann method for generalized
  Newtonian fluid flows

abstract:
  In this article, we present a detailed asymptotic analysis of the lattice
Boltzmann method with two different collision mechanisms of BGK-type on the
D2Q9-lattice for generalized Newtonian fluids. Unlike that based on the
Chapman-Enskog expansion leading to the compressible Navier-Stokes equations,
our analysis gives the incompressible ones directly and exposes certain
important features of the lattice Boltzmann solutions. Moreover, our analysis
provides a theoretical basis for using the iteration to compute the
rate-of-strain tensor, which makes sense specially for generalized Newtonian
fluids. As a by-product, a seemingly new structural condition on the
generalized Newtonian fluids is singled out. This condition reads as "the
magnitude of the stress tensor increases with increasing the shear rate". We
verify this condition for all the existing constitutive relations which are
known to us. In addition, it it straightforward to extend our analysis to MRT
models or to three-dimensional lattices.


title:
The Future of Neutrino Mass Measurements: Terrestrial, Astrophysical,
  and Cosmological Measurements in the Next Decade. Highlights of the NuMass
  2013 Workshop. Milano, Italy, February 4 - 7, 2013

abstract:
  The third Workshop of the NuMass series ("The Future of Neutrino Mass
Measurements: Terrestrial, Astrophysical, and Cosmological Measurements in the
Next Decade: NuMass 2013") was held at Dipartimento di Fisica "G. Occhialini,
University of Milano-Bicocca in Milano, Italy, on 4-7 February 2013. The goal
of this international workshop was to review the status and future of direct
and indirect neutrino mass measurements in the laboratory as well as from
astrophysical and cosmological observations. This paper collects most of the
contributions presented during the Workshop.


title: BGG resolutions via configuration spaces

abstract:
  We study the blow-ups of configuration spaces. These spaces have a structure
of what we call an Orlik-Solomon manifold; it allows us to compute the
intersection cohomology of certain flat connections with logarithmic
singularities using some Aomoto type complexes of logarithmic forms. Using this
construction we realize geometrically the sl_2 Bernstein - Gelfand - Gelfand
resolution as an Aomoto complex.


title: Rings of invariants for modular representations of the Klein four group

abstract:
  We study the rings of invariants for the indecomposable modular
representations of the Klein four group. For each such representation we
compute the Noether number and give minimal generating sets for the Hilbert
ideal and the field of fractions. We observe that, with the exception of the
regular representation, the Hilbert ideal for each of these representations is
a complete intersection.


title:
$QQ^{\prime} \bar u \bar d$ bound state in the Bethe-Salpeter equation
  approach

abstract:
  In the heavy quark limit, we establish the Bethe-Salpeter equations for the
ground state $QQ^{\prime} \bar u \bar d$ containing one heavy diquark
$QQ^{\prime}$ ($Q, Q^{\prime}=b$ or $c$) and one light antidiquark $\bar u \bar
d$. We solve the Bethe-Salpeter equations numerically in the covariant
instantaneous approximations with the kernels containing a scalar confinement
term and a one-gluon-exchange term. Numerical solutions for the Bethe-Salpeter
wave functions are presented. The results show that the masses of $bb \bar u
\bar d$, $bc \bar u \bar d$, and $cc \bar u \bar d$ bound states lie below the
threshold of $\bar{B}^{*0}\,B^-$ or $B^0\,{B^*}^-$, $B^-D^+$ or $\bar{B}^{0}
D^0$, and $D^+\,{D^*}^0$ or ${D^*}^+\,D^0$ mesons, respectively. The ground
states $QQ^{\prime} \bar u \bar d$ may exist and we expect the forthcoming
experimental data to confirm them.


title:
Disparity between H\alpha\ and H\beta\ in SN 2008in: inhomogeneous
  external layers of type IIP supernovae?

abstract:
  We study disparity between H\alpha\ and H\beta\ in early spectra of the type
IIP supernova SN 2008in. The point is that these lines cannot be described
simultaneously in a spherically-symmetric model with the smooth density
distribution. It is shown that an assumption of a clumpy structure of external
layers of the envelope resolves the problem. We obtain estimates of the
velocity at the inner border of the inhomogeneous zone (\approx6100 km s^{-1}),
the filing factor of inhomogeneities (\leq0.5), and the mass of the
inhomogeneous layers (~ 0.03 M_{\odot}). The amplitude of flux fluctuations in
the early spectrum of H\alpha\ (\Delta F/F ~ 10^{-2}) imposes a constraint on
the size of inhomogeneities (\leq 200 km s^{-1}). A detection of fluctuations
in the early H\alpha\ of type IIP supernovae might become an observational test
of the inhomogeneous structure of their envelopes. We propose also the indirect
test of the clumpy structure of external layers: the study of properties of the
initial radiation outburst due to the shock breakout. The inhomogeneous
structure of external layers of type IIP supernovae could be an outcome of
density perturbations and density inversion in outer convective layers of
presupernova red supergiant.


title:
Influence of random pinning on the crystallization process in
  suspensions of hard spheres

abstract:
  We discuss crystal formation in supersaturated suspensions of monodisperse
hard spheres with a concentration of hard spheres randomly pinned in space and
time. The pinning procedure introduces an external length scale and an external
time scale that restrict the accessible number of configurations and ultimately
the number of pathways leading to crystallization. We observe a significant
drop in the nucleation rate density at a characteristic pinning concentration
that can be directly related to the structure of the critical nucleus and the
dynamics of its formation in the unpinned system.


title: Aspects of likelihood inference

abstract:
  I review the classical theory of likelihood based inference and consider how
it is being extended and developed for use in complex models and sampling
schemes.


title: Performance Analysis of Massive MIMO for Cell-Boundary Users

abstract:
  In this paper, we consider massive multiple-input multiple-output (MIMO)
systems for both downlink and uplink scenarios, where three radio units (RUs)
connected via one digital unit (DU) support multiple user equipments (UEs) at
the cell-boundary through the same radio resource, i.e., the same
time-frequency slot. For downlink transmitter options, the study considers
zero-forcing (ZF) and maximum ratio transmission (MRT), while for uplink
receiver options it considers ZF and maximum ratio combining (MRC). For the sum
rate of each of these, we derive simple closed-form formulas. In the simple but
practically relevant case where uniform power is allocated to all downlink data
streams, we observe that, for the downlink, vector normalization is better for
ZF while matrix normalization is better for MRT. For a given antenna and user
configuration, we also derive analytically the signal-to-noise-ratio (SNR)
level below which MRC should be used instead of ZF. Numerical simulations
confirm our analytical results.


title:
Partial Sums Generation Architecture for Successive Cancellation
  Decoding of Polar Codes

abstract:
  Polar codes are a new family of error correction codes for which efficient
hardware architectures have to be defined for the encoder and the decoder.
Polar codes are decoded using the successive cancellation decoding algorithm
that includes partial sums computations. We take advantage of the recursive
structure of polar codes to introduce an efficient partial sums computation
unit that can also implements the encoder. The proposed architecture is
synthesized for several codelengths in 65nm ASIC technology. The area of the
resulting design is reduced up to 26% and the maximum working frequency is
improved by ~25%.


title: Rough wall effect on micro-swimmers

abstract:
  We study the effect of a rough wall on the controllability of micro-swimmers
made of several balls linked by thin jacks: the so-called 3-sphere and 4-sphere
swimmers. We show that a controllable swimmer (the 4-sphere swimmer) is not
impacted by the roughness. On the contrary, we show that the roughness changes
the dynamics of the 3-sphere swimmer, so that it can reach any direction almost
everywhere.


title: A single exponential bound for the redundant vertex Theorem on surfaces

abstract:
  Let s1, t1,. . . sk, tk be vertices in a graph G embedded on a surface \sigma
of genus g. A vertex v of G is "redundant" if there exist k vertex disjoint
paths linking si and ti (1 \lequal i \lequal k) in G if and only if such paths
also exist in G - v. Robertson and Seymour proved in Graph Minors VII that if v
is "far" from the vertices si and tj and v is surrounded in a planar part of
\sigma by l(g, k) disjoint cycles, then v is redundant. Unfortunately, their
proof of the existence of l(g, k) is not constructive. In this paper, we give
an explicit single exponential bound in g and k.


title: MPBART - Multinomial Probit Bayesian Additive Regression Trees

abstract:
  This article proposes Multinomial Probit Bayesian Additive Regression Trees
(MPBART) as a multinomial probit extension of BART - Bayesian Additive
Regression Trees (Chipman et al (2010)). MPBART is flexible to allow inclusion
of predictors that describe the observed units as well as the available choice
alternatives. Through two simulation studies and four real data examples, we
show that MPBART exhibits very good predictive performance in comparison to
other discrete choice and multiclass classification methods. To implement
MPBART, we have developed an R package mpbart available freely from CRAN
repositories.


title:
On LHC searches for CP-violating, dimension-6 electroweak gauge boson
  operators

abstract:
  We reconsider the prospects for observing a dimension-6, CP-violating
operator involving $W^+W^-Z$ at the LHC. Firstly, we correct a number of
earlier calculations of the loop contribution to the neutron electric dipole
moment of a companion operator, involving $W^+W^-\gamma$, showing that
measurements imply a very strong bound on the companion operator. Secondly, we
quantify the link between the two operators, showing that strongly-coupled new
physics could only be observable in proposed searches if it appeared at a scale
below $\sim 170$ GeV. This is most unlikely, given the null results of other
searches at the LHC and elsewhere.


title: The role of detachment of in-links in scale-free networks

abstract:
  Real-world networks may exhibit detachment phenomenon determined by the
cancelling of previously existing connections. We discuss a tractable extension
of Yule model to account for this feature. Analytical results are derived and
discussed both asymptotically and for a finite number of links. Comparison with
the original model is performed in the supercritical case. The first-order
asymptotic tail behavior of the two models is similar but differences arise in
the second-order term. We explicitly refer to World Wide Web modeling and we
show the agreement of the proposed model on very recent data. However, other
possible network applications are also mentioned.


title: Linear Regression from Strategic Data Sources

abstract:
  Linear regression is a fundamental building block of statistical data
analysis. It amounts to estimating the parameters of a linear model that maps
input features to corresponding outputs. In the classical setting where the
precision of each data point is fixed, the famous Aitken/Gauss-Markov theorem
in statistics states that generalized least squares (GLS) is a so-called "Best
Linear Unbiased Estimator" (BLUE). In modern data science, however, one often
faces strategic data sources, namely, individuals who incur a cost for
providing high-precision data.
  In this paper, we study a setting in which features are public but
individuals choose the precision of the outputs they reveal to an analyst. We
assume that the analyst performs linear regression on this dataset, and
individuals benefit from the outcome of this estimation. We model this scenario
as a game where individuals minimize a cost comprising two components: (a) an
(agent-specific) disclosure cost for providing high-precision data; and (b) a
(global) estimation cost representing the inaccuracy in the linear model
estimate. In this game, the linear model estimate is a public good that
benefits all individuals. We establish that this game has a unique non-trivial
Nash equilibrium. We study the efficiency of this equilibrium and we prove
tight bounds on the price of stability for a large class of disclosure and
estimation costs. Finally, we study the estimator accuracy achieved at
equilibrium. We show that, in general, Aitken's theorem does not hold under
strategic data sources, though it does hold if individuals have identical
disclosure costs (up to a multiplicative factor). When individuals have
non-identical costs, we derive a bound on the improvement of the equilibrium
estimation cost that can be achieved by deviating from GLS, under mild
assumptions on the disclosure cost functions.


title: Radiation Pressure Confinement - I. Ionized Gas in the ISM of AGN Hosts

abstract:
  We analyze the hydrostatic effect of AGN radiation pressure on optically
thick gas in the host galaxy. We show that in luminous AGN, the radiation
pressure likely confines the ionized layer of the illuminated gas. Radiation
pressure confinement (RPC) has two main implications. First, the gas density
near the ionization front is 7x10^4 L_{i,45} r_{50}^{-2} cm^{-3}, where
L_{i,45} is the ionizing luminosity in units of 10^45 erg/s and r_{50} is the
distance of the gas from the nucleus in units of 50 pc. Second, as shown by
Dopita et al., the solution of the ionization structure within each slab is
unique, independent of the ambient pressure. We show that the RPC density vs.
distance relation is observed over a dynamical range of ~10^4 in distance, from
sub-pc to kpc from the nucleus, and a range of ~10^8 in gas density, from 10^3
to 10^11 cm^{-3}. This relation implies that the radiative force of luminous
AGN can compress giant molecular clouds in the host galaxy, and possibly affect
the star formation rate. The unique ionization structure in RPC includes a
highly ionized X-ray emitting surface, an intermediate layer which emits
coronal lines, and a lower ionization inner layer which emits optical lines.
This structure can explain the observed overlap of the extended X-ray and
optical narrow line emission in nearby AGN. We further support RPC by comparing
the predicted ratios of the narrow lines strength and narrow line widths with
available observations. We suggest a new method, based on the narrow line
widths, to estimate the black hole mass of low luminosity AGN.


title: On Diophantine exponents in dimension 4

abstract:
  We obtain some new inequalities between the ordinary and the uniform
Diophantine exponents for simultaneous Diophantine approximation to four real
numbers.


title: Entropic force, running gravitational coupling and future singularities

abstract:
  The effects of a running gravitational coupling and the entropic force on
future singularities are considered. Although it is expected that the quantum
corrections remove the future singularities or change the singularity type,
treating the running gravitational coupling as a function of energy density is
found to cause no change in the type of singularity but causes a delay in the
time that a singularity occurs. The entropic force is found to replaces the
singularity type $II$ by $\bar{III}$ ($a=$const., $H=$const., $\dot{H} \to
\infty$, $p \to \infty$, $\rho \to \infty$) which differs from previously known
type $III$ and to remove the $w$-singularity. We also consider an effective
cosmological model and show that the types $I$ and $II$ are replaced by the
singularity type $III$.


title: A search for extensible low-WAFOM point sets

abstract:
  Matsumoto, Saito, and Matoba recently proposed the Walsh figure of merit
(WAFOM), which is a computable criterion for quasi-Monte Carlo point sets using
digital nets. Several algorithms have been proposed for finding low-WAFOM point
sets. In the existing algorithms, the number of points is fixed in advance, but
extensible point sets are preferred in some applications. In this paper, we
propose a random search algorithm for extensible low-WAFOM point sets. For
this, we introduce a method that uses lookup tables to compute WAFOM faster.
Numerical results show that our extensible low-WAFOM point sets are comparable
with Niederreiter--Xing sequences for some low-dimensional and smooth test
functions.


title: Alpha-Concave Hull, a Generalization of Convex Hull

abstract:
  Bounding hull, such as convex hull, concave hull, alpha shapes etc. has vast
applications in different areas especially in computational geometry. Alpha
shape and concave hull are generalizations of convex hull. Unlike the convex
hull, they construct non-convex enclosure on a set of points. In this paper, we
introduce another generalization of convex hull, named alpha-concave hull, and
compare this concept with convex hull and alpha shape. We show that the
alpha-concave hull is also a generalization of an NP-complete problem named
min-area TSP. We prove that computing the alpha-concave hull is NP-hard on a
set of points.


title: Properties of Linearly Sofic Groups

abstract:
  We consider (projectively) linearly sofic groups, i.e. groups which can be
approximated using (projective) matrices over arbitrary fields, as a
generalization of sofic groups. We generalize known results for sofic groups
and groups which can be approximated with complex matrices, including the fact
that free products of linearly sofic groups (using a fixed field) are linearly
sofic.


title: MadAnalysis 5: status and new developments

abstract:
  MadAnalysis 5 is a new Python/C++ package facilitating phenomenological
analyses that can be performed in the framework of Monte Carlo simulations of
collisions to be produced in high-energy physics experiments. It allows, by
means of a user-friendly interpreter, to perform professional physics analyses
in a very simple way. Starting from event samples as generated by any Monte
Carlo event generator, large classes of selections can be implemented through
intuitive commands, many standard kinematical distributions can be
automatically represented by histograms and all results are eventually gathered
into detailed Html and latex reports. In this work, we briefly report on the
latest developments of the code, focusing on the interface to the FastJet
program dedicated to jet reconstruction.


title:
Characterization of the degree sequences of (quasi) regular uniform
  hypergraphs

abstract:
  In hypergraph theory, determining a characterization of the degree sequence
$d=(d_1,d_2,\ldots,d_n)$ where $d_1\ge d_2\ge\ldots,d_n$ are positive integers,
of an $h$-uniform simple hypergraph $\cal H$, and deciding the complexity
status of the reconstruction of $\cal H$ from $d$, are two challenging open
problems. They can be formulated in the context of discrete tomography: asks
whether there is a matrix $A$ with positive projection vectors
$H=(h,h,\ldots,h)$ and $V=(d_1,d_2,\ldots,d_n)$ with distinct rows. In this
paper we consider the two subcases where the vector $V$ is an homogeneous
vector, and where $V$ is almost homogeneous, i.e., $d_1-d_n=1$. We give a
simple characterization for these two subcases, and we show how to solve the
related reconstruction problems in polynomial time. To reach our goal, we use
the concepts of Lyndon words and necklaces of fixed density, and we apply some
already known algorithms for their efficient generation.


title: Hedging in L\'evy Models and the Time Step Equivalent of Jumps

abstract:
  We consider option hedging in a model where the underlying follows an
exponential L\'evy process. We derive approximations to the variance-optimal
and to some suboptimal strategies as well as to their mean squared hedging
errors. The results are obtained by considering the L\'evy model as a
perturbation of the Black-Scholes model. The approximations depend on the first
four moments of logarithmic stock returns in the L\'evy model and option price
sensitivities (greeks) in the limiting Black-Scholes model. We illustrate
numerically that our formulas work well for a variety of L\'evy models
suggested in the literature. From a theoretical point of view, it turns out
that jumps have a similar effect on hedging errors as discrete-time hedging in
the Black-Scholes model.


title: Maximum Waring ranks of monomials

abstract:
  We show that monomials and sums of pairwise coprime monomials in four or more
variables have Waring rank less than the generic rank, with a short list of
exceptions. We asymptotically compare their ranks with the generic rank.


title: Stability of point spectrum for three-state quantum walks on a line

abstract:
  Evolution operators of certain quantum walks possess, apart from the
continuous part, also point spectrum. The existence of eigenvalues and the
corresponding stationary states lead to partial trapping of the walker in the
vicinity of the origin. We analyze the stability of this feature for
three-state quantum walks on a line subject to homogenous coin deformations. We
find two classes of coin operators that preserve the point spectrum. These new
classes of coins are generalizations of coins found previously by different
methods and shed light on the rich spectrum of coins that can drive
discrete-time quantum walks.


title:
Pitch-angle scattering in magnetostatic turbulence. I. Test-particle
  simulations and the validity of analytical results

abstract:
  Context. Spacecraft observations have motivated the need for a refined
description of the phase-space distribution function. Of particular importance
is the pitch-angle diffusion coefficient that occurs in the Fokker-Planck
transport equation. Aims. Simulations and analytical test-particle theories are
compared to verify the diffusion description of particle transport, which does
not allow for non-Markovian behavior. Methods. A Monte-Carlo simulation code
was used to trace the trajectories of test particles moving in turbulent
magnetic fields. From the ensemble average, the pitch-angle Fokker-Planck
coefficient is obtained via the mean square displacement. Results. It is shown
that, while excellent agreement with analytical theories can be obtained for
slab turbulence, considerable deviations are found for isotropic turbulence. In
addition, all Fokker-Planck coefficients tend to zero for high time values.


title: The geometry of least squares in the 21st century

abstract:
  It has been over 200 years since Gauss's and Legendre's famous priority
dispute on who discovered the method of least squares. Nevertheless, we argue
that the normal equations are still relevant in many facets of modern
statistics, particularly in the domain of high-dimensional inference. Even
today, we are still learning new things about the law of large numbers, first
described in Bernoulli's Ars Conjectandi 300 years ago, as it applies to high
dimensional inference. The other insight the normal equations provide is the
asymptotic Gaussianity of the least squares estimators. The general form of the
Gaussian distribution, Gaussian processes, are another tool used in modern
high-dimensional inference. The Gaussian distribution also arises via the
central limit theorem in describing weak convergence of the usual least squares
estimators. In terms of high-dimensional inference, we are still missing the
right notion of weak convergence. In this mostly expository work, we try to
describe how both the normal equations and the theory of Gaussian processes,
what we refer to as the "geometry of least squares," apply to many questions of
current interest.


title:
Pitch-angle scattering in magnetostatic turbulence. II. Analytical
  considerations and pitch-angle isotropization

abstract:
  Aims. The process of pitch-angle isotropization is important for many
applications ranging from diffusive shock acceleration to large-scale
cosmic-ray transport. Here, the basic analytical description is revisited on
the basis of recent simulation results. Methods. Both an analytical and a
numerical investigation were undertaken of the Fokker-Planck equation for
pitch-angle scattering. Additional test-particle simulations obtained with the
help of a Monte-Carlo code were used to verify the conclusions. Results. It is
shown that the usual definition of the pitch-angle Fokker-Planck coefficient
via the mean-square displacement is flawed. The reason can be traced back to
the assumption of homogeneity in time which does not hold for pitch-angle
scattering. Conclusions. Calculating the mean free path via the Fokker-Planck
coefficient has often proven to give an accurate description. For numerical
purposes, accordingly, it is the definition that has to be exchanged in favor
of the pitch-angle correlation function.


title:
Spin-polarized angle-resolved photoelectron spectroscopy of the
  so-predicted Kondo topological insulator SmB6

abstract:
  Undoped and slightly Eu-doped SmB6 show the opening of a gap with decreasing
temperature below ~150 K. The spectral shapes near the Fermi level (EF) at 15 K
have shown strong increase in intensity of a peak at a binding energy (EB) of
around 12 meV with decreasing the photon energy (hn) from 17 eV down to 7 eV.
Angle resolved spectra of SmB6 measured at hn = 35 eV just after the in-situ
cleavage showed clear dispersions of several bands in the EB region from EF to
4 eV. Spin-polarized photoelectron spectra were then measured at 12 K and light
incidence angle of ~50 deg. In contrast to the lack of spin polarization for
the linearly polarized light excitation, clear spin polarization was observed
in the case of circularly polarized light excitation. The two prominent peaks
at EB~12 and ~150 meV have shown opposite signs of spin polarization which are
reversed when the helicity of the light is reversed. The sign and the magnitude
of spin- polarization are consistent with a theoretical prediction for the
6H5/2 and 6H7/2 states.


title:
Neutron scattering and muon spin relaxation measurements of the
  non-centrosymmetric antiferromagnet CeCoGe3

abstract:
  The magnetic states of the non-centrosymmetric, pressure induced
superconductor CeCoGe3 have been studied with magnetic susceptibility, muon
spin relaxation(muSR), single crystal neutron diffraction and inelastic neutron
scattering (INS). CeCoGe3 exhibits three magnetic phase transitions at T_N1 =
21 K, T_N2 = 12 K and T_N3 = 8 K. The presence of long range magnetic order
below T_N1 is revealed by the observation of oscillations of the asymmetry in
the muSR spectra between 13 K and 20 K and a sharp increase in the muon
depolarization rate. Single crystal neutron diffraction measurements reveal
magnetic Bragg peaks consistent with propagation vectors of k = 2/3 between
T_N1 and T_N2, k = 5/8between T_N2 and T_N3 and k = 1/2 below T_N3. An increase
in intensity of the (1 1 0) reflection between T_N1 and T_N3 also indicates a
ferromagnetic component in these phases. These measurements are consistent with
an equal moment, two-up, two-down magnetic structure below T_N3, with a
magnetic moment of 0.405(5) mu_B/Ce. Above T_N2, the results are consistent
with an equal moment, two-up, one-down structure with a moment of 0.360(6)
mu_B/Ce. INS studies reveal two crystal-field (CEF) excitations at 19 and 27
meV. From an analysis with a CEF model, the wave-functions of the J = 5/2
multiplet are evaluated along with a prediction for the magnitude and direction
of the ground state magnetic moment. Our model correctly predicts that the
moments order along the c axis but the observed magnetic moment of 0.405(5)
mu_B is reduced compared to the predicted moment of 1.01 mu_B. This is ascribed
to hybridization between the localized Ce^3+ f-electrons and the conduction
band. This suggests that CeCoGe3 has a degree of hybridization between that of
CeRhGe3 and the non-centrosymmetric superconductor CeRhSi3.


title: Asynchronous Gossip for Averaging and Spectral Ranking

abstract:
  We consider two variants of the classical gossip algorithm. The first variant
is a version of asynchronous stochastic approximation. We highlight a
fundamental difficulty associated with the classical asynchronous gossip
scheme, viz., that it may not converge to a desired average, and suggest an
alternative scheme based on reinforcement learning that has guaranteed
convergence to the desired average. We then discuss a potential application to
a wireless network setting with simultaneous link activation constraints. The
second variant is a gossip algorithm for distributed computation of the
Perron-Frobenius eigenvector of a nonnegative matrix. While the first variant
draws upon a reinforcement learning algorithm for an average cost controlled
Markov decision problem, the second variant draws upon a reinforcement learning
algorithm for risk-sensitive control. We then discuss potential applications of
the second variant to ranking schemes, reputation networks, and principal
component analysis.


title: Difference Balanced Functions and Their Generalized Difference Sets

abstract:
  Difference balanced functions from $F_{q^n}^*$ to $F_q$ are closely related
to combinatorial designs and naturally define $p$-ary sequences with the ideal
two-level autocorrelation. In the literature, all existing such functions are
associated with the $d$-homogeneous property, and it was conjectured by Gong
and Song that difference balanced functions must be $d$-homogeneous. First we
characterize difference balanced functions by generalized difference sets with
respect to two exceptional subgroups. We then derive several necessary and
sufficient conditions for $d$-homogeneous difference balanced functions. In
particular, we reveal an unexpected equivalence between the $d$-homogeneous
property and multipliers of generalized difference sets. By determining these
multipliers, we prove the Gong-Song conjecture for $q$ prime. Furthermore, we
show that every difference balanced function must be balanced or an affine
shift of a balanced function.


title:
Energy Efficient Telemonitoring of Physiological Signals via Compressed
  Sensing: A Fast Algorithm and Power Consumption Evaluation

abstract:
  Wireless telemonitoring of physiological signals is an important topic in
eHealth. In order to reduce on-chip energy consumption and extend sensor life,
recorded signals are usually compressed before transmission. In this paper, we
adopt compressed sensing (CS) as a low-power compression framework, and propose
a fast block sparse Bayesian learning (BSBL) algorithm to reconstruct original
signals. Experiments on real-world fetal ECG signals and epilepsy EEG signals
showed that the proposed algorithm has good balance between speed and data
reconstruction fidelity when compared to state-of-the-art CS algorithms.
Further, we implemented the CS-based compression procedure and a low-power
compression procedure based on a wavelet transform in Filed Programmable Gate
Array (FPGA), showing that the CS-based compression can largely save energy and
other on-chip computing resources.


title: On the Probability Distributions of Ellipticity

abstract:
  In this paper we derive an exact full expression for the 2D probability
distribution of the ellipticity of an object measured from data, only assuming
Gaussian noise in pixel values. This is a generalisation of the probability
distribution for the ratio of single random variables, that is well-known, to
the multivariate case. This expression is derived within the context of the
measurement of weak gravitational lensing from noisy galaxy images. We find
that the third flattening, or epsilon-ellipticity, has a biased maximum
likelihood but an unbiased mean; and that the third eccentricity, or normalised
polarisation chi, has both a biased maximum likelihood and a biased mean. The
very fact that the bias in the ellipticity is itself a function of the
ellipticity requires an accurate knowledge of the intrinsic ellipticity
distribution of the galaxies in order to properly calibrate shear measurements.
We use this expression to explore strategies for calibration of biases caused
by measurement processes in weak gravitational lensing. We find that upcoming
weak lensing surveys like KiDS or DES require calibration fields of order of
several square degrees and 1.2 magnitude deeper than the wide survey in order
to correct for the noise bias. Future surveys like Euclid will require
calibration fields of order 40 square degree and several magnitude deeper than
the wide survey. We also investigate the use of the Stokes parameters to
estimate the shear as an alternative to the ellipticity. We find that they can
provide unbiased shear estimates at the cost of a very large variance in the
measurement. The python code used to compute the distributions presented in the
paper and to perform the numerical calculations are available on request.


title: Visualizing Basins of Attraction for Different Minimization Algorithms

abstract:
  We report a study of the basins of attraction for potential energy minima
defined by different minimisation algorithms for an atomic system. We find that
whereas some minimisation algorithms produce compact basins, others produce
basins with complex boundaries or basins consisting of disconnected parts. Such
basins deviate from the "correct" basin of attraction defined by
steepest-descent pathways, and the differences can be controlled to some extent
by adjustment of the maximum step size. The choice of the most convenient
minimisation algorithm depends on the problem in hand. We show that while
L-BFGS is the fastest minimiser, the FIRE algorithm is also quite fast, and can
lead to less fragmented basins of attraction.


title:
Infinite soliton and kink-soliton trains for nonlinear Schr\"odinger
  equations

abstract:
  We look for solutions to generic nonlinear Schr\"odinger equations build upon
solitons and kinks. Solitons are localized solitary waves and kinks are their
non localized counter-parts. We prove the existence of infinite soliton trains,
i.e. solutions behaving at large time as the sum of infinitely many solitons.
We also show that one can attach a kink at one end of the train. Our proofs
proceed by fixed point arguments around the desired profile. We present two
approaches leading to different results, one based on a combination of
dispersive estimates and Strichartz estimates, the other based only on
Strichartz estimates.


title: Warped Extra Dimensional Benchmarks for Snowmass 2013

abstract:
  The framework of a warped extra dimension with the Standard Model (SM) fields
propagating in it is a very well-motivated extension of the SM since it can
address both the Planck-weak and flavor hierarchy problems of the SM. We
consider signals at the 14 and 33 TeV large hadron collider (LHC) resulting
from the direct production of the new particles in this framework,
i.e.,Kaluza-Klein (KK) excitations of the SM particles. We focus on spin-1
(gauge boson) and spin-2 (graviton) KK particles and their decays to top/bottom
quarks (flavor-conserving) and W/Z and Higgs bosons, in particular. We propose
two benchmarks for this purpose, with the right-handed (RH) or LH top quark,
respectively, being localized very close to the TeV end of the extra dimension.
We present some new results at the 14 TeV (with 300 fb$^-1$ and 3000 fb$^-1$)
and 33 TeV LHC. We find that the prospects for discovery of these particles are
quite promising, especially at the high-luminosity upgrade.


title: N and Z odd-even staggering in Kr + Sn collisions at Fermi energies

abstract:
  The odd-even staggering of the yield of final reaction products has been
studied as a function of proton (Z) and neutron (N) numbers for the collisions
84 Kr+112 Sn and 84 Kr+124 Sn at 35 MeV/nucleon, in a wide range of elements
(up to Z ~ 20). The experimental data show that staggering effects rapidly
decrease with increasing size of the fragments. Moreover the staggering in N is
definitely larger than the one in Z. Similar general features are qualitatively
reproduced by the GEMINI code. Concerning the comparison of the two systems,
the staggering in N is in general rather similar, being slightly larger only
for the lightest fragments produced in the n-rich system. In contrast the
staggering in Z, although smaller than that in N, is sizably larger for the
n-poor system with respect to the n-rich one.


title: Algebraic $S$-integers of fixed degree and bounded height

abstract:
  Let $k$ be a number field and $S$ a finite set of places of $k$ containing
the archimedean ones. We count the number of algebraic points of bounded height
whose coordinates lie in the ring of $S$-integers of $k$. Moreover, we give an
asymptotic formula for the number of $\bar{S}$-integers of bounded height and
fixed degree over $k$, where $\bar{S}$ is the set of places of $\bar{k}$ lying
above the ones in $S$.


title:
Topology near the transition temperature in lattice gluodynamics
  analyzed by low lying modes of the overlap Dirac operator

abstract:
  Topological objects of $SU(3)$ gluodynamics are studied at the infrared scale
near the transition temperature with the help of zero and near-zero modes of
the overlap Dirac operator. We construct UV filtered topological charge
densities corresponding to three versions of the temporal boundary condition
applied to this operator, for which the zero mode is known to be located on
corresponding three constituent dyons (antidyons) in the reference case of an
analytical (anti)caloron solution. The clustering of the three topological
charge densities marks the positions of three types of dyons and antidyons
which can therefore be considered as present in equilibrium (Monte Carlo)
gluonic fields at the given resolution scale. We classify them either as
constituents of nondissociated (anti)calorons or as constituents of (anti)dyon
pairs or as isolated (anti)dyons. The pattern of the Polyakov loop describing
the centers and the interior of these clusters is observed after a limited
number of overimproved cooling steps and resembles the description known from
analytical caloron solutions.


title:
Angular momentum evolution of young low-mass stars and brown dwarfs:
  observations and theory

abstract:
  This chapter aims at providing the most complete review of both the emerging
concepts and the latest observational results regarding the angular momentum
evolution of young low-mass stars and brown dwarfs. In the time since
Protostars & Planets V, there have been major developments in the availability
of rotation period measurements at multiple ages and in different star-forming
environments that are essential for testing theory. In parallel, substantial
theoretical developments have been carried out in the last few years, including
the physics of the star-disk interaction, numerical simulations of stellar
winds, and the investigation of angular momentum transport processes in stellar
interiors. This chapter reviews both the recent observational and theoretical
advances that prompted the development of renewed angular momentum evolution
models for cool stars and brown dwarfs. While the main observational trends of
the rotational history of low mass objects seem to be accounted for by these
new models, a number of critical open issues remain that are outlined in this
review.


title: Entanglement Entropy of Extremal BTZ

abstract:
  In this note, we use entanglement entropy as a tool to explore the universal
properties of CFTs dual to extremal BTZ black holes. We demonstrate that the
entanglement entropies computed in the CFTs at the boundary of the extremal BTZ
and the boundary of the near-horizon limit of the extremal BTZ are in perfect
agreement and have the form appropriate to a two-dimensional CFT with only the
chiral part excited and the anti-chiral in the ground state. Furthermore, we
analyze the universal limits of the entanglement entropy and recover the
correct value of the thermal entropy for large entangling intervals and the
first-law like relation for the small interval.


title: Densities of primes and realization of local extensions

abstract:
  In this paper we introduce new densities on the set of primes of a number
field. If $K/K_0$ is a Galois extension of number fields, we associate to any
element $x \in {\rm Gal}_{K/K_0}$ a density $\delta_{K/K_0,x}$ on primes of
$K$. In particular, the density associated to $x = 1$ is the usual Dirichlet
density on $K$. After establishing some properties of these densities, we use
them to show that the maximal solvable extension of a number field unramified
outside an almost Chebotarev set realize the maximal local extension at each
prime lying outside this set.


title:
Noninner automorphisms of order p in finite p-groups of coclass 2, when
  p > 2

abstract:
  It is shown that if G is a finite p-group of coclass 2 with p > 2, then G has
a noninner automorphism of order p.


title: Formation and evolution of an active region filament

abstract:
  Several scenarios explaining how filaments are formed can be found in
literature. In this paper, we analyzed the observations of an active region
filament and critically evaluated the observed properties in the context of
current filament formation models. This study is based on multi-height
spectropolarimetric observations. The inferred vector magnetic field has been
extrapolated starting either from the photosphere or from the chromosphere. The
line-of-sight motions of the filament, which was located near disk center, have
been analyzed inferring the Doppler velocities. We conclude that a part of the
magnetic structure emerged from below the photosphere.


title: Algebraic tensor products and internal homs of noncommutative L^p-spaces

abstract:
  We prove that the multiplication map L^a(M)\otimes_M L^b(M)\to L^{a+b}(M) is
an isometric isomorphism of (quasi)Banach M-M-bimodules. Here L^a(M)=L_{1/a}(M)
is the noncommutative L_p-space of an arbitrary von Neumann algebra M and
\otimes_M denotes the algebraic tensor product over M equipped with the
(quasi)projective tensor norm, but without any kind of completion. Similarly,
the left multiplication map L^a(M)\to Hom_M(L^b(M),L^{a+b}(M)) is an isometric
isomorphism of (quasi)Banach M-M-bimodules, where Hom_M denotes the algebraic
internal hom. In particular, we establish an automatic continuity result for
such maps. Applications of these results include establishing explicit
algebraic equivalences between the categories of L_p(M)-modules of Junge and
Sherman for all p\ge0, as well as identifying subspaces of the space of
bilinear forms on L^p-spaces.


title: Generalized system identification with stable spline kernels

abstract:
  Regularized least-squares approaches have been successfully applied to linear
system identification. Recent approaches use quadratic penalty terms on the
unknown impulse response defined by stable spline kernels, which control model
space complexity by leveraging regularity and bounded-input bounded-output
stability. This paper extends linear system identification to a wide class of
nonsmooth stable spline estimators, where regularization functionals and data
misfits can be selected from a rich set of piecewise linear-quadratic (PLQ)
penalties. This class includes the 1-norm, Huber, and Vapnik, in addition to
the least-squares penalty.
  By representing penalties through their conjugates, the modeler can specify
any piecewise linear-quadratic penalty for misfit and regularizer, as well as
inequality constraints on the response. The interior-point solver we implement
(IPsolve) is locally quadratically convergent, with $O(\min(m,n)^2(m+n))$
arithmetic operations per iteration, where $n$ the number of unknown impulse
response coefficients and $m$ the number of observed output measurements.
IPsolve is competitive with available alternatives for system identification.
This is shown by a comparison with TFOCS, libSVM, and the FISTA algorithm. The
code is open source (https://github.com/saravkin/IPsolve).
  The impact of the approach for system identification is illustrated with
numerical experiments featuring robust formulations for contaminated data,
relaxation systems, nonnegativity and unimodality constraints on the impulse
response, and sparsity promoting regularization. Incorporating constraints
yields particularly significant improvements.


title:
Cohomological finiteness conditions and centralisers in generalisations
  of Thompson's group V

abstract:
  We consider generalisations of Thompson's group $V$, denoted $V_r(\Sigma)$,
which also include the groups of Higman, Stein and Brin. We show that, under
some mild hypotheses, $V_r(\Sigma)$ is the full automorphism group of a
Cantor-algebra. Under some further minor restrictions, we prove that these
groups are of type $\mathrm{F}_\infty$ and that this implies that also
centralisers of finite subgroups are of type $\mathrm{F}_\infty$.


title:
Computing Coulomb Interaction in Inhomogeneous Dielectric Media via a
  Local Electrostatics Lattice Algorithm

abstract:
  The local approach to computing electrostatic interactions proposed by Maggs
and adapted by Pasichnyk for molecular dynamics simulations is extended to
situations where the dielectric background medium is inhomogeneous. We
furthermore correct a problem of the original algorithm related to the correct
treatment of the global dipole moment, provide an error estimate for the
accuracy of the algorithm, and suggest a different form of the treatment of the
self-energy problem. Our implementation is highly scalable on many cores, and
we have validated and compared its performance against theoretical predictions
and simulation data obtained by other algorithmic approaches.


title: Dynamical regimes of dissipative quantum systems

abstract:
  We reveal several distinct regimes of the relaxation dynamics of a small
quantum system coupled to an environment within the plane of the dissipation
strength and the reservoir temperature. This is achieved by discriminating
between coherent dynamics with damped oscillatory behavior on all time scales,
partially coherent behavior being nonmonotonic at intermediate times but
monotonic at large ones, and purely monotonic incoherent decay. Surprisingly,
elevated temperature can render the system `more coherent' by inducing a
transition from the partially coherent to the coherent regime. This provides a
refined view on the relaxation dynamics of open quantum systems.


title: High-resolution spectroscopy of a giant solar filament

abstract:
  High-resolution spectra of a giant solar quiescent filament were taken with
the Echelle spectrograph at the Vacuum Tower Telescope (VTT; Tenerife, Spain).
A mosaic of various spectroheliograms (H\alpha, H\alpha\ +/- 0.5\AA\ and Na D2)
were chosen to examine the filament at different heights in the solar
atmosphere. In addition, full-disk images (He I 10830\AA\ and Ca II K) of the
Chromspheric Telescope and full-disk magnetograms of the Helioseismic and
Magnetic Imager were used to complement the spectra. Preliminary results are
shown of this filament, which had extremely large linear dimensions (~ 740'')
and was observed in November 2011 while it traversed the northern solar
hemisphere.


title: SPICA spectroscopic cosmological surveys to unravel galaxy evolution

abstract:
  The main energy-generating mechanisms in galaxies are black hole (BH)
accretion and star formation (SF) and the interplay of these processes is
driving the evolution of galaxies. MIR/FIR spectroscopy are able to distinguish
between BH accretion and SF, as it was shown in the past by infrared
spectroscopy from the space by the Infrared Space Observatory and Spitzer.
Spitzer and Herschel spectroscopy together can trace the AGN and the SF
components in galaxies, with extinction free lines, almost only in the local
Universe, except for a few distant objects. One of the major goals of the study
of galaxy evolution is to understand the history of the luminosity source of
galaxies along cosmic time. This goal can be achieved with far-IR spectroscopic
cosmological surveys. SPICA in combination with ground based large single dish
submillimeter telescopes, such as CCAT, will offer a unique opportunity to do
this. We use galaxy evolution models linked to the observed MIR-FIR counts
(including Herschel) to predict the number of sources and their IR lines
fluxes, as derived from observations of local galaxies. A shallow survey in an
area of 0.5 square degrees, with a typical integration time of 1 hour per
pointing, will be able to detect thousands of galaxies in at least three
emission lines, using SAFARI, the far-IR spectrometer onboard of SPICA.


title:
Single calcium-40 ion as quantum memory for photon polarization: a case
  study

abstract:
  We present several schemes for heralded storage of polarization states of
single photons in single ions, using the calcium-40 ion and photons at 854 nm
wavelength as specific example. We compare the efficiencies of the schemes and
the requirements for their implementation with respect to the preparation of
the initial state of the ion, the absorption process and its analysis. These
schemes may be used to create and herald entanglement of two distant ions
through entanglement swapping; they are easily adapted to other atomic systems
and wavelengths.


title:
Free convection over a non-isothermal axisymmetric body immersed in a
  porous medium saturated with an electrically conducting non-Newtonian fluid

abstract:
  The study investigates the problem of magnetohydrodynamic (MHD) free
convection over a non-isothermal axisymmetric body under the action of
transverse magnetic field. The body is embedded in a porous medium saturated
with electrically conducting non-Newtonian power law fluid. In order to obtain
similarity solution, it is assumed that the viscosity of the fluid decays
exponentially with temperature. The qualitative results are illustrated for a
vertical flat plate, horizontal cylinder and sphere.


title:
Dynamical multifractal zeta-functions, multifractal pressure and fine
  multifractal spectra

abstract:
  We introduce multifractal pressure and dynamical multifractal zeta-functions
providing precise information of a very general class of multifractal spectra,
including, for example, the fine multifractal spectra of self-conformal
measures and the fine multifractal spectra of ergodic Birkhoff averages of
continuous functions.


title: Optimal Coordinate as a General Method in Stochastic Dynamics

abstract:
  A general method to describe stochastic dynamics of Markov processes is
suggested. The method aims to solve three related problems. The determination
of an optimal coordinate for the description of stochastic dynamics. The
reconstruction of time from an ensemble of stochastic trajectories. The
decomposition of stationary stochastic dynamics on eigen-modes which do not
decay exponentially with time. The problems are solved by introducing additive
eigenvectors which are transformed by a stochastic matrix in a simple way -
every component is translated on a constant distance. Such solutions have
peculiar properties. For example, an optimal coordinate for stochastic dynamics
with detailed balance is a multi-valued function. An optimal coordinate for a
random walk on the line corresponds to the conventional eigenvector of the one
dimensional Dirac equation. The equation for the optimal coordinate in a slow
varying potential reduces to the Hamilton-Jacobi equation for the action
function.


title: Effect of plasma composition on accretion on to black holes

abstract:
  Matter makes a transition from non-relativistic to relativistic regime, as it
falls onto a black hole. We employ a relativistic equation of state,
abbreviated as RC, to study multi-species fluid flow around black holes. We
show that pair-plasma fluid around a black hole is thermally not relativistic.
In order to make it relativistic, a finite baryon loading is necessary. As a
consequence of this, pair-plasma flow do not suffer centrifugal pressure driven
shock in accretion. However, fluid with finite baryon content may undergo shock
transition.


title: DPHEP: From Study Group to Collaboration

abstract:
  The international study group on data preservation in high energy physics,
DPHEP, achieved a milestone in 2012 with the publication of its eagerly
anticipated large scale report, which contains a description of data
preservation activities from all major high energy physics collider-based
experiments and laboratories. DPHEP will evolve to a new collaboration
structure in 2013. The formation of the study group is described, as well as
some of the key messages from the report focussing on the physics case for the
preservation of high energy physics data and a description of the different
preservation models. Finally, the future working directions of the new
collaboration are outlined.


title: Quantum cluster algebra structures on quantum nilpotent algebras

abstract:
  All algebras in a very large, axiomatically defined class of quantum
nilpotent algebras are proved to possess quantum cluster algebra structures
under mild conditions. Furthermore, it is shown that these quantum cluster
algebras always equal the corresponding upper quantum cluster algebras.
Previous approaches to these problems for the construction of (quantum) cluster
algebra structures on (quantized) coordinate rings arising in Lie theory were
done on a case by case basis relying on the combinatorics of each concrete
family. The results of the paper have a broad range of applications to these
problems, including the construction of quantum cluster algebra structures on
quantum unipotent groups and quantum double Bruhat cells (the
Berenstein-Zelevinsky conjecture), and treat these problems from a unified
perspective. All such applications also establish equality between the
constructed quantum cluster algebras and their upper counterparts. The proofs
rely on Chatters' notion of noncommutative unique factorization domains. Toric
frames are constructed by considering sequences of homogeneous prime elements
of chains of noncommutative UFDs (a generalization of the construction of
Gelfand-Tsetlin subalgebras) and mutations are obtained by altering chains of
noncommutative UFDs. Along the way, an intricate (and unified) combinatorial
model for the homogeneous prime elements in chains of noncommutative UFDs and
their alterations is developed. When applied to special families, this recovers
the combinatorics of Weyl groups and double Weyl groups previously used in the
construction and categorification of cluster algebras. It is expected that this
combinatorial model of sequences of homogeneous prime elements will have
applications to the unified categorification of quantum nilpotent algebras.


title: Finite-size scaling in unbiased translocation dynamics

abstract:
  Finite-size scaling arguments naturally lead us to introduce a
coordinate-dependent diffusion coefficient in a Fokker-Planck description of
the late stage dynamics of unbiased polymer translocation through a membrane
pore. The solution for the probability density function of the chemical
coordinate matches the initial-stage subdiffusive regime and takes into account
the equilibrium entropic drive. Precise scaling relations connect the
subdiffusion exponent to the divergence with the polymer length of the
translocation time, and also to the singularity of the probability density
function at the absorbing boundaries. Quantitative comparisons with numerical
simulation data in $d=2$ strongly support the validity of the model and of the
predicted scalings.


title: On the Information Content of Stellar Spectra

abstract:
  With the increasing quality of asteroseismic observations it is important to
minimize the random and systematic errors in mode parameter estimates. To this
end it is important to understand how the oscillations relate to the directly
observed quantities, such as intensities and spectra, and to derived
quantities, such as Doppler velocity. Here I list some of the effects we need
to take into account and show an example of the impact of some of them.


title: AdS-Sliced Flavor Branes and Adding Flavor to the Janus Solution

abstract:
  We implement D7 flavor branes in AdS-sliced coordinates on $AdS_5\times S^5$
with the ansatz that the brane fluctuates only in the warped ($\mu$) direction
in this slicing, which is particularly appropriate for studying the Janus
solution. The natural field theory dual in this slicing is $\mathcal{N}=4$
super Yang-Mills on two copies of $AdS_4$. Branes extending from $\mu=\pm\pi/2$
can end at different locations, giving rise to quarks with piecewise constant
mass on each $AdS_4$ half-space, jumping discontinuously between them. A second
class of flavor brane solutions exists in this coordinate system, dubbed
"continuous" flavor branes, that extend across the entire range of $\mu$. We
propose that the correct dual interpretation of "disconnected" flavor brane in
this ansatz is a quark hypermultiplet with constant mass on one of the AdS$_4$
half-spaces with totally reflecting boundary conditions at the boundary of
AdS$_4$; whereas the dual interpretation of a continuous flavor brane has
totally transparent boundary conditions. Numerical studies indicate that
AdS-sliced D7 flavor branes of both classes exhibit spontaneous chiral symmetry
breaking, as non-zero vev persists for solutions of the equation of motion down
to zero mass. Continuous flavor branes in this ansatz exhibit many other
surprising behaviors: their masses seem to be capped at a modest value near
$m=0.551$ in units of the inverse AdS radius, and there may be a phase
transition between continuous branes of different configurations. We also
numerically study quark states in Janus. The behavior of mass and vev is
similar in Janus, including the existence of chiral symmetry breaking at zero
mass, though qualitative features of the phase diagram change (sometimes
significantly) as the Janus parameter $c_0$ increases.


title:
Modelling photometric reverberation data -- a disk-like broad-line
  region and a potentially larger black hole mass for 3C120

abstract:
  We consider photometric reverberation mapping, where the nuclear continuum
variations are monitored via a broad-band filter and the echo of emission line
clouds of the broad line region (BLR) is measured with a suitable narrow-band
(NB) filter. We investigate how an incomplete emission-line coverage by the NB
filter influences the BLR size determination. This includes two basic cases: 1)
a symmetric cut of the blue and red part of the line wings, and 2) the filter
positioned asymmetrically to the line centre so that essentially a complete
half of the emission line is contained in the NB filter. Under the assumption
that the BLR size is dominated by circular Keplerian orbits, we find that
symmetric cutting of line wings may lead to overestimating the BLR size by less
than 5%. The case of asymmetric half-line coverage, similar as for our data of
the Seyfert 1 galaxy 3C120, yields the BLR size with a bias of less than 1%.
Our results suggest that any BLR size bias due to narrow-band line cut in
photometric reverberation mapping is small and in most cases negligible. We
used well sampled photometric reverberation mapping light curves with sharp
variation features in both the continuum and the Hbeta light curves to
determine the geometry type of the Hbeta BLR for 3C120. Modelling of the light
curve, under the assumption that the BLR is essentially virialised, argues
against a spherical geometry and favours a nearly face-on disk-like geometry
with inclination i = 10 +/- 4 deg and extension from 22 to 28 light days. The
low inclination may lead to a larger black hole mass than the derived when
using the average geometry scaling factor f=5.5. We discuss deviations of
Seyfert 1 galaxies from the M_BH - sigma relation.


title: Edge number critical triangle free graphs with low independence numbers

abstract:
  The structure of all triangle free graphs G = (V,E) with |E| - 6|V| +
13\alpha(G) = 0 is determined, yielding an affirmative answer to a question of
Stanis{\l}aw Radziszowski and Donald Kreher.


title: Vortex Dynamics in Cerebral Aneurysms

abstract:
  We use an autonomous three-dimensional dynamical system to study embedded
vortex structures that are observed to form in computational fluid dynamic
simulations of patient-specific cerebral aneurysm geometries. These structures,
described by a vortex which is enclosed within a larger vortex flowing in the
opposite direction, are created and destroyed in phase space as fixed points
undergo saddle-node bifurcations along vortex core lines. We illustrate how
saddle-node bifurcations along vortex core lines also govern the formation and
evolution of embedded vortices in cerebral aneurysms under variable inflow
rates during the cardiac cycle.


title:
Demonstration of fold and cusp catastrophes in an atomic cloud reflected
  from an optical barrier in the presence of gravity

abstract:
  We experimentally demonstrate first-order (fold) and second-order (cusp)
catastrophes in the density of an atomic cloud reflected from an optical
barrier in the presence of gravity, and show their corresponding universal
asymptotic behavior. The cusp point enables robust, field-free refocusing of an
expanding atomic cloud with a wide velocity distribution. Specifically, the
density attained at the cusp point in our experiment reached 65% of the peak
density of the atoms in the trap prior to their release. We thereby add
caustics to the various phenomena with parallels in optics that can be
harnessed for manipulation of cold atoms. The structural stability of
catastrophes provides inherent robustness against variations in the system's
dynamics and initial conditions, making them suitable for manipulation of atoms
under imperfect conditions and limited controllability.


title:
Stability and Dynamics of Cross Solitons in Harmonically Confined
  Bose-Einstein Condensates

abstract:
  We examine the stability and dynamics of a family of crossed dark solitons in
a harmonically confined Bose-Einstein condensate in two dimensions. Working in
a regime where the fundamental snake instability is suppressed, we show the
existence of an instability which leads to an interesting collapse and revival
of the initial state for the fundamental case of two crossed solitons. The
instability originates from the singular point where the solitons cross, and we
characterise it by examining the Bogoliubov spectrum. Finally, we extend the
treatment to systems of higher symmetry.


title:
Strongly Intensive Measures for Transverse Momentum and Particle Number
  Fluctuations

abstract:
  The strongly intensive measures $\Delta[P_T,N]$ and $\Sigma[P_T,N]$ are used
to study the event-by-event fluctuations of the transverse momentum $P_T$ and
particle multiplicity $N$ in nucleus-nucleus collisions.
  A special normalization for these fluctuation measures ensures that they are
dimensionless and yields a common scale required for a quantitative comparison
of fluctuations. In this paper basic properties of the $\Delta[P_T, N]$ and
$\Sigma[P_T, N]$ measures are tested within different phenomenological models
using the Monte Carlo simulations (the so-called fast generators) and
analytical solutions. The obtained results are helpful to elucidate the
properties of $\Delta[P_T,N]$ and $\Sigma[P_T,N]$ measures.


title:
Polarization effects in the cascade decay Lambda_b -> Lambda(-> p pi-) +
  J/psi(-> l+ l-) in the covariant confined quark model

abstract:
  We calculate the invariant and helicity amplitudes for the nonleptonic decay
Lambda_b -> Lambda + J/psi, psi(2S) in the covariant confined quark model. We
discuss joint angular decay distributions in the cascade decay Lambda_b ->
Lambda(-> p pi-) + J/psi, psi(2S) (-> l+ l-) and calculate some of the
asymmetry parameters that characterize the joint angular decay distribution. We
confirm expectations from the naive quark model that the transitions into the
lambda_Lambda=1/2 helicity states of the daughter baryon Lambda are strongly
suppressed leading to a near maximal negative polarization of the Lambda. For
the same reason the azimuthal correlation between the two decay planes spanned
by (p pi-) and (l+ l-) is negligibly small. We provide form factor results for
the whole accessible q2-range. Our results are close to lattice results at
minimum recoil and light-cone sum rule results at maximum recoil. A new feature
of our analysis is that we include lepton mass effects in the calculation which
allows us to also describe the cascade decay Lambda_b -> Lambda(-> p pi-) +
psi(2S)(-> tau+ tau-).


title: Higgs -> $\gamma\gamma$, $Z\gamma$ in the Inert Doublet Model

abstract:
  An analysis of the Higgs boson decay rates to $\gamma\gamma$ and $Z\gamma$ in
the Inert Doublet Model is presented. We study the correlation between the two
rates and perform extended analysis of the two-photon rate
($R_{\gamma\gamma}$). We study both the possibility of enhancing and
suppressing $R_{\gamma\gamma}$ and find constraints for masses of the scalar
particles (in particular the dark matter (DM) candidate and the charged scalar)
and their couplings to the Higgs boson. We also combine the resulting
constraints with those following from the WMAP measurements of the DM relic
density, obtaining stringent constraints on different dark matter scenarios.


title:
On the Performance of Network Coding and Forwarding Schemes with
  Different Degrees of Redundancy for Wireless Mesh Networks

abstract:
  This study explores the throughput and delay that can be achieved by various
forwarding schemes employing multiple paths and different degrees of redundancy
focusing on linear network coding. The key contribution of the study is an
analytical framework for modeling the throughput and delay for various schemes
considering wireless mesh networks where, unicast traffic is forwarded and
hop-by-hop retransmissions are employed for achieving reliability. The
analytical framework is generalized for an arbitrary number of paths and hops
per path. Another key contribution of the study is the evaluation and extension
of the numerical results drawn from the analysis through NS-2 simulations. Our
results show that in scenarios with significant interference the best
throughput-delay tradeoff is achieved by single path forwarding. Moreover, when
significant interference is present and network coding employs the larger
packet generation size it experiences higher delay than all other schemes due
to the inter-arrival times aggregating over all coded packets required to
decode a packet generation.


title:
The complex of formal operations on the Hochschild chains of commutative
  algebras

abstract:
  We compute the homology of the complex of formal operations on the Hochschild
complex of differential graded commutative algebras as defined by Wahl and
prove that these can be built as infinite sums of operations obtained from
Loday's shuffle operations, Connes' boundary operator and the shuffle product.


title: Correlations and textures in the neutrino mass matrix

abstract:
  The recent enormous improvement of our knowledge of the neutrino oscillation
parameters has motivated us to reinvestigate the allowed ranges of the elements
of the neutrino mass matrix in the basis where the charged-lepton mass mass
matrix is diagonal. Moreover, we have studied the correlations of the elements
of the neutrino mass matrix. The result of this analysis is useful for finding
textures in the neutrino mass matrix and, therefore, for model building in the
lepton sector. As an example, we present two textures of the neutrino mass
matrix which have only two parameters and fit very well all current
experimental data on the neutrino parameters.


title: Riemannian foliations of spheres

abstract:
  We show that a Riemannian foliation on a topological $n$-sphere has leaf
dimension 1 or 3 unless n=15 and the Riemannian foliation is given by the
fibers of a Riemannian submersion to an 8-dimensional sphere. This allows us to
classify Riemannian foliations on round spheres up to metric congruence.


title: Schutt's theorem for vector-valued sequence spaces

abstract:
  The entropy numbers of certain finite-dimensional operators acting between
vector-valued sequence spaces are estimated, thus providing a generalization of
the famous result of Schutt. In addition, two-sided estimates of the entropy
numbers of some diagonal operators are obtained.


title: Logarithmically-small Minors and Topological Minors

abstract:
  Mader proved that for every integer $t$ there is a smallest real number
$c(t)$ such that any graph with average degree at least $c(t)$ must contain a
$K_t$-minor. Fiorini, Joret, Theis and Wood conjectured that any graph with $n$
vertices and average degree at least $c(t)+\epsilon$ must contain a $K_t$-minor
consisting of at most $C(\epsilon,t)\log n$ vertices. Shapira and Sudakov
subsequently proved that such a graph contains a $K_t$-minor consisting of at
most $C(\epsilon,t)\log n \log\log n$ vertices. Here we build on their method
using graph expansion to remove the $\log\log n$ factor and prove the
conjecture.
  Mader also proved that for every integer $t$ there is a smallest real number
$s(t)$ such that any graph with average degree larger than $s(t)$ must contain
a $K_t$-topological minor. We prove that, for sufficiently large $t$, graphs
with average degree at least $(1+\epsilon)s(t)$ contain a $K_t$-topological
minor consisting of at most $C(\epsilon,t)\log n$ vertices. Finally, we show
that, for sufficiently large $t$, graphs with average degree at least
$(1+\epsilon)c(t)$ contain either a $K_t$-minor consisting of at most
$C(\epsilon,t)$ vertices or a $K_t$-topological minor consisting of at most
$C(\epsilon,t)\log n$ vertices.


title: Structural, Magnetic, and Superconducting Properties of Ba1-xNaxFe2As2

abstract:
  We report the results of a systematic investigation of the phase diagram of
the iron-based superconductor system, Ba1-xNaxFe2As2, from x = 0.1 to x = 1.0
using high resolution neutron and x-ray diffraction and magnetization
measurements. We find that the coincident structural and magnetic phase
transition to an orthorhombic (O) structure with space group Fmmm and a striped
antiferromagnet (AF) with space group F(C)mm'm' in Ba1-xNaxFe2As2 is of first
order. A complete suppression of the magnetic phase is observed by x = 0.30,
and bulk superconductivity occurs at a critical concentration near 0.15. We
compare the new findings to the previously reported results of the hole-doped
Ba1-xKxFe2As2 solid solution in order to resolve the differing effects of band
filling and A-site cation size on the properties of the magnetic and
superconducting ground states. The substantial size difference between Na and K
causes various changes in the lattice trends, yet the overarching property
phase diagram from the Ba1-xKxFe2As2 phase diagram carries over to the
Ba1-xNaxFe2As2 solid solution. We note that the composition dependence of the c
axis turns over from positive to negative around x = 0.35, unlike the
K-substituted materials. We show that this can be understood by invoking steric
effects; primarily the Fe2As2 layer shape is dictated mostly by the electronic
filling, which secondarily induces an interlayer spacing adjusted to compensate
for the given cation volume. This exemplifies the primacy of even subtle
features in the Fe2As2 layer in controlling both the structure and properties
in the uncollapsed 122 phases.


title: Inner Product in Quantum Field Theory

abstract:
  In this paper we will analyse the inner product for a general tensor field
theory. We will first analyse a generalized inner product for scalar field
theories. Then we will use it to construct a inner product for tensor field
theories. We will use this inner product to construct the two-point function.


title: Does Information Have Mass?

abstract:
  Does information have mass? This question has been asked many times and there
are many answers even on the Internet, including on Yahoo Answers. Usually the
answer is "no". Attempts have been made to assess the physical mass of
information by estimating the mass of electrons feeding the power-guzzling
computers and devices making up the Internet, the result being around 50 gram.
Other efforts to calculate the mass of information have assumed that each
electron involved in signal transfer carries one bit of information, which
makes the corresponding mass to be about 10^-5 gram. We address the fundamental
question of minimum mass related to a bit of information from the angles of
quantum physics and special relativity. Our results indicate that there are
different answers depending on the physical situation, and sometimes the mass
can even be negative. We tend to be skeptical about the earlier mass
estimations, mentioned above, because our results indicate that the electron's
mass does not play a role in any one of them.


title:
Monte Carlo tools for studies of non-standard electroweak gauge boson
  interactions in multi-boson processes: A Snowmass White Paper

abstract:
  In this Snowmass 2013 white paper, we review the effective field theory
approach for studies of non-standard electroweak interactions in electroweak
vector boson pair and triple production and vector boson scattering. We present
an overview of the implementation of dimension six and eight operators in
MadGraph5, VBFNLO, and WHIZARD, and provide relations between the coefficients
of these higher dimensions operators used in these programs and in the
anomalous couplings approach. We perform a tuned comparison of predictions for
multi-boson processes including non-standard electroweak interactions with
MadGraph5, VBFNLO, and WHIZARD. We discuss the role of higher-order corrections
in these predictions using VBFNLO and a POWHEG BOX implementation of
higher-order QCD corrections to WWjj production. The purpose of this white
paper is to collect useful tools for the study of non-standard EW physics at
the LHC, compare them, and study the main physics issues in the relevant
processes.


title:
Tree Deletion Set has a Polynomial Kernel (but no OPT^O(1)
  approximation)

abstract:
  In the Tree Deletion Set problem the input is a graph G together with an
integer k. The objective is to determine whether there exists a set S of at
most k vertices such that G-S is a tree. The problem is NP-complete and even
NP-hard to approximate within any factor of OPT^c for any constant c. In this
paper we give a O(k^4) size kernel for the Tree Deletion Set problem. To the
best of our knowledge our result is the first counterexample to the
"conventional wisdom" that kernelization algorithms automatically provide
approximation algorithms with approximation ratio close to the size of the
kernel. An appealing feature of our kernelization algorithm is a new algebraic
reduction rule that we use to handle the instances on which Tree Deletion Set
is hard to approximate.


title:
Observation of a topological 3D Dirac semimetal phase in high-mobility
  Cd3As2

abstract:
  Experimental identification of three-dimensional (3D) Dirac semimetals in
solid state systems is critical for realizing exotic topological phenomena and
quantum transport such as the Weyl phases, high temperature linear quantum
magnetoresistance and topological magnetic phases. Using high resolution
angle-resolved photoemission spectroscopy, we performed systematic electronic
structure studies on well-known compound Cd3As2. For the first time, we observe
a highly linear bulk Dirac cone located at the Brillouin zone center projected
onto the (001) surface which is consistent with a 3D Dirac semimetal phase in
Cd3As2. Remarkably, an unusually high Dirac Fermion velocity up to 10.2
\textrm{\AA}{\cdot}$eV (1.5 \times 10^{6} ms^-1) is seen in samples where the
mobility far exceeds 40,000 cm^2/V.s suggesting that Cd3As2 can be a promising
candidate as a hypercone analog of graphene in many device-applications which
can also incorporate topological quantum phenomena in a large gap setting. Our
experimental identification of this novel topological 3D Dirac semimetal phase,
distinct from a 3D topological insulator phase discovered previously, paves the
way for exploring higher dimensional relativistic physics in bulk transport and
for realizing novel Fermionic matter such as a Fermi arc nodal metal.


title: New Modes of Nuclear Excitations

abstract:
  We present a theoretical approach based on density functional theory
supplemented by a microscopic multi-phonon model which is applied for
investigations of pygmy resonances and other excitations of different
multipolarities in stable and exotic nuclei. The possible relation of
low-energy modes to the properties of neutron or proton skins is systematically
studied in isotonic and isotopic chains. The fine structure of nuclear electric
and magnetic response functions is analyzed and compared to experimental data.
Their relevance to nuclear astrophysics is discussed.


title: Inference of Inhomogeneous Clouds in an Exoplanet Atmosphere

abstract:
  We present new visible and infrared observations of the hot Jupiter Kepler-7b
to determine its atmospheric properties. Our analysis allows us to 1) refine
Kepler-7b's relatively large geometric albedo of Ag=0.35+-0.02, 2) place upper
limits on Kepler-7b thermal emission that remains undetected in both Spitzer
bandpasses and 3) report a westward shift in the Kepler optical phase curve. We
argue that Kepler-7b's visible flux cannot be due to thermal emission or
Rayleigh scattering from H2 molecules. We therefore conclude that high
altitude, optically reflective clouds located west from the substellar point
are present in its atmosphere. We find that a silicate-based cloud composition
is a possible candidate. Kepler-7b exhibits several properties that may make it
particularly amenable to cloud formation in its upper atmosphere. These include
a hot deep atmosphere that avoids a cloud cold trap, very low surface gravity
to suppress cloud sedimentation, and a planetary equilibrium temperature in a
range that allows for silicate clouds to potentially form in the visible
atmosphere probed by Kepler. Our analysis does not only present evidence of
optically thick clouds on Kepler-7b but also yields the first map of clouds in
an exoplanet atmosphere.