title: The Geometry of Spherical Random Fields

abstract:
  In this PhD Thesis we investigate the geometry of random fields on compact
Riemannian manifolds, in particular the two-dimensional sphere. In the first
part, we characterize isotropic Gaussian fields on homogeneous spaces of a
compact group and then we prove the non-existence of P. L\'evy's Brownian field
on the group SO(3), which moreover allows to extend the same kind of result to
SO(n), SU(n) for n bigger than 3. In the second part, we investigate the
high-energy behavior of random eigenfunctions on the (hyper)sphere and on the
torus proving quantitative CLT results for some geometric functionals of those
eiegenfunctions. A nice non-Central and non-Universal result is shown for nodal
length distribution in the case of arithmetic random waves. Finally, we extend
representation formulas obtained in the first part to the case of spin random
fields on the sphere, introducing a new approach i.e., the pullback random
field, that easily allows to study random sections of homogeneous vector
bundles.


title:
Power and Channel Allocation for Non-orthogonal Multiple Access in 5G
  Systems: Tractability and Computation

abstract:
  Network capacity calls for significant increase for 5G cellular systems. A
promising multi-user access scheme, non-orthogonal multiple access (NOMA) with
successive interference cancellation (SIC), is currently under consideration.
In NOMA, spectrum efficiency is improved by allowing more than one user to
simultaneously access the same frequency-time resource and separating
multi-user signals by SIC at the receiver. These render resource allocation and
optimization in NOMA different from orthogonal multiple access in 4G. In this
paper, we provide theoretical insights and algorithmic solutions to jointly
optimize power and channel allocation in NOMA. For utility maximization, we
mathematically formulate NOMA resource allocation problems. We characterize and
analyze the problems' tractability under a range of constraints and utility
functions. For tractable cases, we provide polynomial-time solutions for global
optimality. For intractable cases, we prove the NP-hardness and propose an
algorithmic framework combining Lagrangian duality and dynamic programming
(LDDP) to deliver near-optimal solutions. To gauge the performance of the
obtained solutions, we also provide optimality bounds on the global optimum.
Numerical results demonstrate that the proposed algorithmic solution can
significantly improve the system performance in both throughput and fairness
over orthogonal multiple access as well as over a previous NOMA resource
allocation scheme.


title: Double power series method for approximating cosmological perturbations

abstract:
  We introduce a double power series method for finding approximate analytical
solutions for systems of differential equations commonly found in cosmological
perturbation theory. The method was set out, in a non-cosmological context, by
Feshchenko, Shkil' and Nikolenko (FSN) in 1966, and is applicable to cases
where perturbations are on sub-horizon scales. The FSN method is essentially an
extension of the well known Wentzel-Kramers-Brillouin (WKB) method for finding
approximate analytical solutions for ordinary differential equations. The FSN
method we use is applicable well beyond perturbation theory to solve systems of
ordinary differential equations, linear in the derivatives, that also depend on
a small parameter, which here we take to be related to the inverse wave-number.
  We use the FSN method to find new approximate oscillating solutions in linear
order cosmological perturbation theory for a flat radiation-matter universe.
Together with this model's well known growing and decaying M\'esz\'aros
solutions, these oscillating modes provide a complete set of sub-horizon
approximations for the metric potential, radiation and matter perturbations.
Comparison with numerical solutions of the perturbation equations shows that
our approximations can be made accurate to within a typical error of 1%, or
better. We also set out a heuristic method for error estimation. A Mathematica
notebook which implements the double power series method is made available
online.


title:
$B_{s,d}^0\rightarrow l^+l^-$ in the minimal gauged $(B-L)$
  supersymmetry

abstract:
  Complete expressions of effective Hamilton for $b\rightarrow
sl^+l^-\;(l=\mu,\;\tau)$ are derived in the framework of minimal supersymmetric
extension of the standard model with local $B-L$ gauge symmetry. With some
assumptions on parameters of the model, a numerical analysis of the
supersymmetric contributions to the branching ratios of $B_s^0\rightarrow
l^+l^-\;(l=\mu,\;\tau)$ is presented.


title:
Target selection of classical pulsating variables for space-based
  photometry

abstract:
  In a few years the Kepler and TESS missions will provide ultra-precise
photometry for thousands of RR Lyrae and hundreds of Cepheid stars. In the
extended Kepler mission all targets are proposed in the Guest Observer (GO)
Program, while the TESS space telescope will work with full frame images and a
~15-16th mag brightness limit with the possibility of short cadence
measurements for a limited number of pre-selected objects. This paper
highlights some details of the enormous and important work of the target
selection process made by the members of Working Group 7 (WG#7) of the Kepler
and TESS Asteroseismic Science Consortium.


title: Ergodicity of L\'evy-Type Processes

abstract:
  In this paper, conditions for transience, recurrence, ergodicity and strong,
subexponential (polynomial) and exponential ergodicity of a class of Feller
processes are derived. The conditions are given in terms of the coefficients of
the corresponding infinitesimal generator. As a consequence, mixing properties
of these processes are also discussed.


title:
TAPAS IV. TYC 3667-1280-1 b - the most massive red giant star hosting a
  warm Jupiter

abstract:
  We present the latest result of the TAPAS project that is devoted to intense
monitoring of planetary candidates that are identified within the
PennState-Toru\'n planet search.
  We aim to detect planetary systems around evolved stars to be able to build
sound statistics on the frequency and intrinsic nature of these systems, and to
deliver in-depth studies of selected planetary systems with evidence of
star-planet interaction processes.
  The paper is based on precise radial velocity measurements: 13 epochs
collected over 1920 days with the Hobby-Eberly Telescope and its
High-Resolution Spectrograph, and 22 epochs of ultra-precise HARPS-N data
collected over 961 days.
  We present a warm-Jupiter ($T_{eq}=1350 K$, $m_{2} sin i=5.4\pm$0.4$M_{J}$)
companion with an orbital period of 26.468 days in a circular ($e=0.036$) orbit
around a giant evolved ($\log g=3.11\pm0.09$, $R=6.26\pm0.86R_{\odot}$) star
with $M_{\star}=1.87\pm0.17M_{\odot}$. This is the most massive and oldest star
found to be hosting a close-in giant planet. Its proximity to its host
($a=0.21au$) means that the planet has a $13.9\pm2.0\%$ probability of
transits; this calls for photometric follow-up study.
  This massive warm Jupiter with a near circular orbit around an evolved
massive star can help set constraints on general migration mechanisms for warm
Jupiters and, given its high equilibrium temperature, can help test energy
deposition models in hot Jupiters.


title: G\"odel and G\"odel-type universes in Brans-Dicke theory

abstract:
  In this paper, conditions for existence of G\"{o}del and G\"{o}del-type
solutions in Brans-Dicke (BD) scalar-tensor theory and their main features are
studied. The consistency of equations of motion, causality violation and
existence of CTCs (closed time-like curves) are investigated. The role which
cosmological constant and Mach principle play to achieve the consistency of
this model is studied.


title: On the uncertain nature of the core of $\boldsymbol{\alpha}$ Cen A

abstract:
  High-quality astrometric, spectroscopic, interferometric and, importantly,
asteroseismic observations are available for $\alpha$ Cen A, which is the
closest binary star system to earth. Taking all these constraints into account,
we study the internal structure of the star by means of theoretical modelling.
Using the Aarhus STellar Evolution Code (ASTEC) and the tools of Computational
Bayesian Statistics, in particular a Markov chain Monte Carlo algorithm, we
perform statistical inferences for the physical characteristics of the star. We
find that $\alpha$ Cen A has a probability of approximately 40% of having a
convective core. This probability drops to few percents if one considers
reduced rates for the $^{14}$N(p,$\gamma$)$^{15}$O reaction. These convective
cores have fractional radii less than 8% when overshoot is neglected. Including
overshooting also leads to the possibility of a convective core mostly
sustained by the ppII chain energy output. We finally show that roughly 30% of
the stellar models describing $\alpha$ Cen A are in the subgiant regime.


title: Source Localization on Graphs via l1 Recovery and Spectral Graph Theory

abstract:
  We cast the problem of source localization on graphs as the simultaneous
problem of sparse recovery and diffusion kernel learning. An l1 regularization
term enforces the sparsity constraint while we recover the sources of diffusion
from a single snapshot of the diffusion process. The diffusion kernel is
estimated by assuming the process to be as generic as the standard heat
diffusion. We show with synthetic data that we can concomitantly learn the
diffusion kernel and the sources, given an estimated initialization. We
validate our model with cholera mortality and atmospheric tracer diffusion
data, showing also that the accuracy of the solution depends on the
construction of the graph from the data points.


title: Number of Distinct Sites Visited by a Random Walk with Internal States

abstract:
  In the classical paper of Dvoretzky-Erd\H{o}s, asymptotics for the expected
value and the variance of the number of distinct sites visited by a Simple
Symmetric Random Walk were calculated. Here, these results are generalized for
Random Walks with Internal States. Moreover, both weak and strong laws of large
numbers are proved. As a tool for these results, the error term of the local
limit theorem in of Kr\'amli and Sz\'asz is also estimated.


title: Recurrence properties of a special type of Heavy-Tailed Random Walk

abstract:
  In the proof of the invariance principle for locally perturbed periodic
Lorentz process with finite horizon, a lot of delicate results were needed
concerning the recurrence properties of its unperturbed version. These were
analogous to the similar properties of Simple Symmetric Random Walk. However,
in the case of Lorentz process with infinite horizon, the analogous results for
the corresponding random walk are not known, either. In this paper, these
properties are ascertained for the appropriate random walk (this happens to be
in the non normal domain of attraction of the normal law). As a tool, an
estimation of the remainder term in the local limit theorem for the
corresponding random walk is computed.


title: Logarithmic scaling of planar random walk's local times

abstract:
  We prove that the local time process of a planar simple random walk, when
time is scaled logarithmically, converges to a non-degenerate pure jump
process. The convergence takes place in the Skorokhod space with respect to the
$M1$ topology and fails to hold in the $J1$ topology.


title: A tight Erd\H{o}s-P\'osa function for long cycles

abstract:
  A classic result of Erd\H{o}s and P\'osa says that any graph contains either
$k$ vertex-disjoint cycles or can be made acyclic by deleting at most $O(k \log
k)$ vertices. Here we generalize this result by showing that for all numbers
$k$ and $l$ and for every graph $G$, either $G$ contains $k$ vertex-disjoint
cycles of length at least $l$, or there exists a set $X$ of $\mathcal
O(kl+k\log k)$ vertices that meets all cycles of length at least $l$ in $G$. As
a corollary, the tree-width of any graph $G$ that does not contain $k$
vertex-disjoint cycles of length at least $l$ is of order $\mathcal O(kl+k\log
k)$. These results improve on the work of Birmel\'e, Bondy and Reed '07 and
Fiorini and Herinckx '14 and are optimal up to constant factors.


title: Non-Archimedean geometry of Artin fans

abstract:
  The purpose of this article is to study the role of Artin fans in tropical
and non-Archimedean geometry. Artin fans are logarithmic algebraic stacks that
can be described completely in terms of combinatorial objects, so called Kato
stacks, a stack-theoretic generalization of K. Kato's notion of a fan. Every
logarithmic algebraic stack admits a tautological strict morphism
$\phi_\mathcal{X}:\mathcal{X}\rightarrow\mathcal{A}_\mathcal{X}$ to an
associated Artin fan. The main result of this article is that, on the level of
underlying topological spaces, the natural functorial tropicalization map of
$\mathcal{X}$ is nothing but the non-Archimedean analytic map associated to
$\phi_\mathcal{X}$ by applying Thuillier's generic fiber functor. Using this
framework, we give a reinterpretation of the main result of
Abramovich-Caporaso-Payne identifying the moduli space of tropical curves with
the non-Archimedean skeleton of the corresponding algebraic moduli space.


title: The first encounter of two billiard particles of small radius

abstract:
  We prove that the time of the first collision between two particles in a
Sinai billiard table converges weakly to an exponential distribution when time
is rescaled by the inverse of the radius of the particles. This results
provides a first step in studying the energy evolution of hard ball systems in
the rare interaction limit.


title:
Fabrication of colloidal Laves phases via hard tetramers and hard
  spheres: bulk phase diagram and sedimentation behaviour

abstract:
  Colloidal photonic crystals display peculiar optical properties which make
them particularly suitable for application in different fields. However, the
low packing fraction of the targeted structures usually poses a real challenge
in the fabrication stage. Here, we propose a novel route to colloidal photonic
crystals via a binary mixture of hard tetramers and hard spheres. By combining
theory and computer simulations, we calculate the phase diagram as well as the
stacking diagram of the mixture, and show that a colloidal analogue of the
MgCu2 Laves phase -- which can serve as a precursor of a photonic bandgap
structure -- is a thermodynamically stable phase in a large region of the phase
diagram. Our findings show a relatively large coexistence region between the
fluid and the Laves phase, which is potentially accessible by experiments.
Furthermore, we determine the sedimentation behaviour of the suggested mixture,
by identifying several stacking sequences. Our work uncovers a new
self-assembly path towards a photonic structure with a band gap in the visible
region.


title:
High-Tc Superconducting Quantum Interference Filters (SQIFs) made by ion
  irradiation

abstract:
  Superconducting Quantum Interference Filters (SQIFs) are arrays of
superconducting loops of different sizes including Josephson Junctions (JJ).
For a random distribution of sizes, they present a non-periodic response to an
applied magnetic field, with an extended linear regime and a sizable field
sensitivity. Such properties make SQIFs interesting devices to detect the
magnetic component of electromagnetic waves at microwave frequencies. We have
used the highly scalable technique of ion irradiation to make High Tc SQUIDs
and SQIFs based on commercial YBa2Cu3O7 films, and studied their properties.
Both display optimum performances as a function of temperature and bias
current, that can be understood in the frame of numerical simulations that we
developed. The role of asymmetries and spread in JJ characteristics (routinely
found in HTSc technologies) is described : ion irradiation based devices appear
robust against them. We finally present results on SQIF made with 2000 SQUID in
series, showing a transfer function dV/dB ~ 1000V/T .


title: Evaluating the Performance of Offensive Linemen in the NFL

abstract:
  How does one objectively measure the performance of an individual offensive
lineman in the NFL? The existing literature proposes various measures that rely
on subjective assessments of game film, but has yet to develop an objective
methodology to evaluate performance. Using a variety of statistics related to
an offensive lineman's performance, we develop a framework to objectively
analyze the overall performance of an individual offensive lineman and
determine specific linemen who are overvalued or undervalued relative to their
salary. We identify eight players across the 2013-2014 and 2014-2015 NFL
seasons that are considered to be overvalued or undervalued and corroborate the
results with existing metrics that are based on subjective evaluation. To the
best of our knowledge, the techniques set forth in this work have not been
utilized in previous works to evaluate the performance of NFL players at any
position, including offensive linemen.


title: Quantum Hall Edge States in Topological Insulator Nanoribbons

abstract:
  We present a microscopic theory of the chiral one-dimensional electron gas
system localized on the sidewalls of magnetically-doped Bi$_2$Se$_3$-family
topological insulator nanoribbons in the quantum anomalous Hall effect (QAHE)
regime. Our theory is based on a simple continuum model of sidewall states
whose parameters are extracted from detailed ribbon and film geometry
tight-binding model calculations. In contrast to the familiar case of the
quantum Hall effect in semiconductor quantum wells, the number of microscopic
chiral channels depends simply and systematically on the ribbon thickness and
on the position of the Fermi level within the surface state gap. We use our
theory to interpret recent transport experiments that exhibit non-zero
longitudinal resistance in samples with accurately quantized Hall conductances.


title: A KAT-7 view of a low-mass sample of galaxy clusters

abstract:
  Radio observations over the last two decades have provided evidence that
diffuse synchrotron emission in the form of megaparsec-scale radio halos in
galaxy clusters is likely tracing regions of the intracluster medium where
relativistic particles are accelerated during cluster mergers. In this paper we
present results of a survey of 14 galaxy clusters carried out with the
7-element Karoo Array Telescope at 1.86 GHz, aimed to extend the current
studies of radio halo occurrence to systems with lower masses (M$_{\rm 500} >
4\times10^{14}$ M${_\odot}$). We found upper limits at the $0.6 - 1.9 \times
10^{24}$ Watt Hz$^{-1}$ level for $\sim 50\%$ of the sample, confirming that
bright radio halos in less massive galaxy clusters are statistically rare.


title: Speckle interferometry at SOAR in 2015

abstract:
  The results of speckle interferometric observations at the SOAR telescope in
2015 are given, totalling 1303 measurements of 924 resolved binary and multiple
stars and non-resolutions of 260 targets. The separations range from 12 mas to
3.37" (median 0.17"); the maximum measured magnitude difference is 6.7 mag. We
resolved 27 pairs for the first time, including 10 as inner or outer subsystems
in previously known binaries, e.g. the 50-mas pair in Epsilon Cha. Newly
resolved pairs are commented upon. We discuss three apparently non-hierarchical
systems discovered in this series, arguing that their unusual configuration
results from projection. The resolved quadruple system HIP 71510 is studied as
well.


title: Exploration of the brown dwarf regime around solar-like stars by CoRoT

abstract:
  Aims. A summary of the CoRoT brown dwarf investigations are presented.
Methods. Transiting brown dwarfs around solar like stars were studied by using
the photometric time-series of CoRoT, and ground based radial velocity
measurements. Results. CoRoT detected three transiting brown dwarfs around F
and G dwarf stars. The occurence rate of brown dwarfs was found to be 0.20 +/-
0.15% around solar-like stars which is compatible with the value obtained by
Kepler-data.


title: Theory of Reciprocating Contact for Viscoelastic Solids

abstract:
  A theory of reciprocating contacts for linear viscoelastic materials is
presented. Results are discussed for the case of a rigid sphere sinusoidally
driven in sliding contact with a viscoelastic half-space. Depending on the size
of the contact, the frequency and amplitude of the reciprocating motion, and on
the relaxation time of the viscoelastic body, we establish that the contact
behavior may range from the steady-state viscoelastic solution, in which
traction forces always oppose the direction of the sliding rigid punch, to a
more elaborate trend, never observed before, which is due to the strong
interaction between different regions of the path covered during the
reciprocating motion. Practical implications span a number of applications,
ranging from seismic engineering to biotechnology.


title:
Chiral nematic self-assembly of minimally surface damaged chitin
  nanofibrils and its load bearing functions

abstract:
  Chitin is one of the most abundant biomaterials in nature, with 10^10 tons
produced annually as hierarchically organized nanofibril fillers to reinforce
the exoskeletons of arthropods. This green and cheap biomaterial has attracted
great attention due to its potential application to reinforce biomedical
materials. Despite that, its practical use is limited since the extraction of
chitin nanofibrils requires surface modification involving harsh chemical
treatments, leading to difficulties in reproducing their natural prototypal
hierarchical structure, i.e. chiral nematic phase. Here, we develop a chemical
etching-free approach using calcium ions, called natural way, to disintegrate
the chitin nanofibrils while keeping the essential moiety for the
self-assembly, ultimately resulting in the reproduction of chitins natural
chiral structure in a polymeric matrix. This chiral chitin nanostructure
exceptionally toughens the composite. Our resultant chiral nematic phase of
chitin materials can contribute to the understanding and use of the reinforcing
strategy in nature.


title:
Self-organization of stress patterns drives state transitions in actin
  cortices

abstract:
  Biological functions rely on ordered structures and intricately controlled
collective dynamics. In contrast to systems in thermodynamic equilibrium, order
is typically established and sustained in stationary states by continuous
dissipation of energy. Non-equilibrium dynamics is a necessary condition to
make the systems highly susceptible to signals that cause transitions between
different states. How cellular processes self-organize under this general
principle is not fully understood. Here, we find that model actomyosin
cortices, in the presence of rapid turnover, display distinct steady states,
each distinguished by characteristic order and dynamics as a function of
network connectivity. The different states arise from a subtle interaction
between mechanical percolation of the actin network and myosin-generated
stresses. Remarkably, myosin motors generate actin architectures, which in
turn, force the emergence of ordered stress patterns. Reminiscent of second
order phase transitions, the emergence of order is accompanied by a critical
regime characterized by strongly enhanced strain fluctuations. The striking
dynamics in the critical regime were revealed using fluorescent single-walled
carbon nanotubes as novel probes of cortical dynamics.


title:
Renormalization Group Improved Higgs Inflation with a Running Kinetic
  Term

abstract:
  We study a Higgs inflation model with a running kinetic term, taking account
of the renormalization group evolution of relevant coupling constants.
Specifically we study two types of the running kinetic Higgs inflation, where
the inflaton potential is given by the quadratic or linear term potential in a
frame where the Higgs field is canonically normalized. We solve the
renormalization group equations at two-loop level and calculate the scalar
spectral index and the tensor-to-scalar ratio. We find that, even if the
renormalization group effects are included, the quadratic inflation is ruled
out by the CMB observations, while the linear one is still allowed.


title: Clustering Time-Series Energy Data from Smart Meters

abstract:
  Investigations have been performed into using clustering methods in data
mining time-series data from smart meters. The problem is to identify patterns
and trends in energy usage profiles of commercial and industrial customers over
24-hour periods, and group similar profiles. We tested our method on energy
usage data provided by several U.S. power utilities. The results show accurate
grouping of accounts similar in their energy usage patterns, and potential for
the method to be utilized in energy efficiency programs.


title: Semantic Regularities in Document Representations

abstract:
  Recent work exhibited that distributed word representations are good at
capturing linguistic regularities in language. This allows vector-oriented
reasoning based on simple linear algebra between words. Since many different
methods have been proposed for learning document representations, it is natural
to ask whether there is also linear structure in these learned representations
to allow similar reasoning at document level. To answer this question, we
design a new document analogy task for testing the semantic regularities in
document representations, and conduct empirical evaluations over several
state-of-the-art document representation models. The results reveal that neural
embedding based document representations work better on this analogy task than
conventional methods, and we provide some preliminary explanations over these
observations.


title:
Multi-Subregion Based Correlation Filter Bank for Robust Face
  Recognition

abstract:
  In this paper, we propose an effective feature extraction algorithm, called
Multi-Subregion based Correlation Filter Bank (MS-CFB), for robust face
recognition. MS-CFB combines the benefits of global-based and local-based
feature extraction algorithms, where multiple correlation filters correspond-
ing to different face subregions are jointly designed to optimize the overall
correlation outputs. Furthermore, we reduce the computational complexi- ty of
MS-CFB by designing the correlation filter bank in the spatial domain and
improve its generalization capability by capitalizing on the unconstrained form
during the filter bank design process. MS-CFB not only takes the d- ifferences
among face subregions into account, but also effectively exploits the
discriminative information in face subregions. Experimental results on various
public face databases demonstrate that the proposed algorithm pro- vides a
better feature representation for classification and achieves higher
recognition rates compared with several state-of-the-art algorithms.


title:
Experimental realization of equiangular three-state quantum key
  distribution

abstract:
  Quantum key distribution using three states in equiangular configuration
combines a security threshold comparable with the one of the Bennett-Brassard
1984 protocol and a quantum bit error rate (QBER) estimation that does not need
to reveal part of the key. We implement an entanglement-based version of the
Renes 2004 protocol, using only passive optic elements in a linear scheme for
the measurement POVM, generating an asymptotic secure key rate of more than 10
kbit/s, with a mean QBER of 1.6%. We then demonstrate its security in the case
of finite key and evaluate the key rate for both collective and general
attacks.


title: Sem\^antica relacional para a l\'ogica proposicional do plaus\'ivel

abstract:
  This article aims to present a neighborhood semantic for a modal logic,
namely, propositional logic of the plausible. As a subnormal character modal
logic, not admits a Kripke semantics. However, the authors show that this
neighborhood semantic, reach a relational semantics for propositional logic of
the plausible.


title: Um modelo alg\'ebrico do quantificador da Ubiquidade

abstract:
  The aim of this article is a deepening of quantification notions in the
aspect of the modular logic. Therefore, it approaches modulated logic of the
plausible that seeks to formalize the quantifier of ubiquity. The text presents
a proposal, introduced by Paul Halmos, to interpret a classical quantifier in
algebraic models and as a original contribution, extends this model to an
algebraic model for the quantifier of ubiquity.


title:
Espa\c{c}os pseudo-topol\'ogicos e descri\c{c}\~oes do conceito de
  plaus\'ivel

abstract:
  The structure of almost topological space is a variation of the concept of
topological space. It emerged as a formalization of a quantifier first order
not definable from the usual existential and universal operators, named the
quantifier of the plausible. Later, it sought a formalization in propositional
logical context, given a deductive and axiomatic system with algebraic model.
We will present these formal conceptions and as an original contribution, we
describe the propositional version of the logic of almost topological spaces in
tableaux.


title:
Contrastive Analysis with Predictive Power: Typology Driven Estimation
  of Grammatical Error Distributions in ESL

abstract:
  This work examines the impact of cross-linguistic transfer on grammatical
errors in English as Second Language (ESL) texts. Using a computational
framework that formalizes the theory of Contrastive Analysis (CA), we
demonstrate that language specific error distributions in ESL writing can be
predicted from the typological properties of the native language and their
relation to the typology of English. Our typology driven model enables to
obtain accurate estimates of such distributions without access to any ESL data
for the target languages. Furthermore, we present a strategy for adjusting our
method to low-resource languages that lack typological documentation using a
bootstrapping approach which approximates native language typology from ESL
texts. Finally, we show that our framework is instrumental for linguistic
inquiry seeking to identify first language factors that contribute to a wide
range of difficulties in second language acquisition.


title:
Going Out of Business: Auction House Behavior in the Massively
  Multi-Player Online Game

abstract:
  The in-game economies of massively multi-player online games (MMOGs) are
complex systems that have to be carefully designed and managed. This paper
presents the results of an analysis of auction house data from the MMOG Glitch,
across a 14 month time period, the entire lifetime of the game. The data
comprise almost 3 million data points, over 20,000 unique players and more than
650 products. Furthermore, an interactive visualization, based on Sankey flow
diagrams, is presented which shows the proportion of the different clusters
across each time bin, as well as the flow of players between clusters. The
diagram allows evaluation of migration of players between clusters as a
function of time, as well as churn analysis. The presented work provides a
template analysis and visualization model for progression-based or
temporal-based analysis of player behavior broadly applicable to games.


title:
Handelman's Positivstellensatz for polynomial matrices positive definite
  on polyhedra

abstract:
  In this paper we give a matrix version of Handelman's Positivstellensatz [1],
representing polynomial matrices which are positive definite on convex, compact
polyhedra. Moreover, we propose also a procedure to find such a representation.
As a corollary of Handelman's theorem, we give a special case of Schm\"udgen's
Positivstellensatz for polynomial matrices positive definite on convex, compact
polyhedra.


title: The 3rd Fermi GBM Gamma-Ray Burst Catalog: The First Six Years

abstract:
  Since its launch in 2008, the Fermi Gamma-ray Burst Monitor (GBM) has
triggered and located on average approximately two gamma-ray bursts (GRB) every
three days. Here we present the third of a series of catalogs of GRBs detected
by GBM, extending the second catalog by two more years, through the middle of
July 2014. The resulting list includes 1405 triggers identified as GRBs. The
intention of the GBM GRB catalog is to provide information to the community on
the most important observables of the GBM detected GRBs. For each GRB the
location and main characteristics of the prompt emission, the duration, peak
flux and fluence are derived. The latter two quantities are calculated for the
50-300~keV energy band, where the maximum energy release of GRBs in the
instrument reference system is observed, and also for a broader energy band
from 10-1000 keV, exploiting the full energy range of GBM's low-energy NaI(Tl)
detectors. Using statistical methods to assess clustering, we find that the
hardness and duration of GRBs are better fitted by a two-component model with
short-hard and long-soft bursts, than by a model with three components.
Furthermore, information is provided on the settings and modifications of the
triggering criteria and exceptional operational conditions during years five
and six in the mission. This third catalog is an official product of the Fermi
GBM science team, and the data files containing the complete results are
available from the High-Energy Astrophysics Science Archive Research Center
(HEASARC).


title: The determinant of the Lax-Phillips scattering operator

abstract:
  Let $M$ denote a finite volume, non-compact Riemann surface without elliptic
points, and let $B$ denote the Lax-Phillips scattering operator. Using the
superzeta function approach due to Voros, we define a Hurwitz-type zeta
function $\zeta^{\pm}_{B}(s,z)$ constructed from the resonances associated to
$zI -[ (1/2)I \pm B]$. We prove the meromorphic continuation in $s$ of
$\zeta^{\pm}_{B}(s,z)$ and, using the special value at $s=0$, define a
determinant of the operators $zI -[ (1/2)I \pm B]$. We obtain expressions for
Selberg's zeta function and the determinant of the scattering matrix in terms
of the operator determinants.


title:
Time-of-flight mass measurements of neutron-rich chromium isotopes up to
  N = 40 and implications for the accreted neutron star crust

abstract:
  We present the mass excesses of 59-64Cr, obtained from recent time-of-flight
nuclear mass measurements at the National Superconducting Cyclotron Laboratory
at Michigan State University. The mass of 64Cr is determined for the first
time, with an atomic mass excess of -33.48(44) MeV. We find a significantly
different two-neutron separation energy S2n trend for neutron-rich isotopes of
chromium, removing the previously observed enhancement in binding at N=38.
Additionally, we extend the S2n trend for chromium to N=40, revealing behavior
consistent with the previously identified island of inversion in this region.
We compare our results to state-of-the-art shell-model calculations performed
with a modified Lenzi-Nowacki-Poves-Sieja interaction in the fp shell,
including the g9/2 and d5/2 orbits for the neutron valence space. We employ our
result for the mass of 64Cr in accreted neutron star crust network calculations
and find a reduction in the strength and depth of electron-capture heating from
the A=64 isobaric chain, resulting in a cooler than expected accreted neutron
star crust. This reduced heating is found to be due to the >1-MeV reduction in
binding for 64Cr with respect to values from commonly used global mass models.


title: A Note on the Optimal Dividends Paid in a Foreign Currency

abstract:
  We consider an insurance entity endowed with an initial capital and a surplus
process modelled as a Brownian motion with drift. It is assumed that the
company seeks to maximise the cumulated value of expected discounted dividends,
which are declared or paid in a foreign currency. The currency fluctuation is
modelled as a L\'evy process. We consider both cases: restricted and
unrestricted dividend payments. It turns out that the value function and the
optimal strategy can be calculated explicitly.


title: Cocycle superrigidity for translation actions of product groups

abstract:
  Let $G$ be either a profinite or a connected compact group, and $\Gamma,
\Lambda$ be finitely generated dense subgroups. Assuming that the left
translation action of $\Gamma$ on $G$ is strongly ergodic, we prove that any
cocycle for the left-right translation action of $\Gamma\times\Lambda$ on $G$
with values in a countable group is virtually cohomologous to a group
homomorphism. Moreover, we prove that the same holds if $G$ is a (not
necessarily compact) connected simple Lie group provided that $\Lambda$
contains an infinite cyclic subgroup with compact closure. We derive several
applications to OE - and W$^*$- superrigidity. In particular, we obtain the
first examples of compact actions of $\mathbb F_2\times\mathbb F_2$ which are
W$^*$-superrigid.


title:
Reconstruction algorithms for a class of restricted ray transforms
  without added singularities

abstract:
  Let $X$ and $X^*$ denote a restricted ray transform along curves and a
corresponding backprojection operator, respectively. Theoretical analysis of
reconstruction from the data $Xf$ is usually based on a study of the
composition $X^* D X$, where $D$ is some local operator (usually a derivative).
If $X^*$ is chosen appropriately, then $X^* D X$ is a Fourier Integral Operator
(FIO) with singular symbol. The singularity of the symbol leads to the
appearance of artifacts (added singularities) that can be as strong as the
original (or, useful) singularities. By choosing $D$ in a special way one can
reduce the strength of added singularities, but it is impossible to get rid of
them completely.
  In the paper we follow a similar approach, but make two changes. First, we
replace $D$ with a nonlocal operator $\tilde D$ that integrates $Xf$ along a
curve in the data space. The result $\tilde D Xf$ resembles the generalized
Radon transform $R$ of $f$. The function $\tilde D Xf$ is defined on pairs
$(x_0,\Theta)\in U\times S^2$, where $U\subset\mathbb R^3$ is an open set
containing the support of $f$, and $S^2$ is the unit sphere in $\mathbb R^3$.
Second, we replace $X^*$ with a backprojection operator $R^*$ that integrates
with respect to $\Theta$ over $S^2$. It turns out that if $\tilde D$ and $R^*$
are appropriately selected, then the composition $R^* \tilde D X$ is an
elliptic pseudodifferential operator of order zero with principal symbol 1.
Thus, we obtain an approximate reconstruction formula that recovers all the
singularities correctly and does not produce artifacts. The advantage of our
approach is that by inserting $\tilde D$ we get access to the frequency
variable $\Theta$. In particular, we can incorporate suitable cut-offs in $R^*$
to eliminate bad directions $\Theta$, which lead to added singularities.


title: Sharp Weighted $L^2$ inequalities for square functions

abstract:
  Using Bellman function approach, we present new proofs of weighted $L^2$
inequalities for square functions, with the optimal dependence on the $A_2$
characteristics of the weight and further explicit constants. We study the
estimates both in the analytic and probabilistic context, and, as application,
obtain related estimates for the classical Lusin and Littlewood-Paley square
functions.


title: The number of direct-sum decompositions of a finite vector space

abstract:
  The theory of q-analogs develops many combinatorial formulas for finite
vector spaces over a finite field with q elements--all in analogy with formulas
for finite sets (which are the special case of q=1). A direct-sum decomposition
of a finite vector space is the vector space analogue of a set partition. This
paper develops the formulas for the number of direct-sum decompositions that
are the q-analogs of the formulas for: (1) the number of set partitions with a
given number partition signature; (2) the number of set partitions of an
n-element set with m blocks (the Stirling numbers of the second kind); and (3)
for the total number of set partitions of an n-element set (the Bell numbers).


title: Dynamics of the diffusive DM-DE interaction--dynamical system approach

abstract:
  We discuss dynamics of a model of an energy transfer between dark energy (DE)
and dark matter (DM). The energy transfer is determined by a non-conservation
law resulting from a diffusion of dark matter in an environment of dark energy.
The relativistic invariance defines the diffusion in a unique way. The system
can contain baryonic matter and radiation which do not interact with the dark
sector. We treat the Friedman equation and the conservation laws as a closed
dynamical system. The dynamics of the model is examined using the dynamical
systems methods for demonstration how solutions depend on initial conditions.
We also fit the model parameters using astronomical observation: SNIa, $H(z)$,
BAO and Alcock-Paczynski test. We show that the model with diffuse DM-DE is
consistent with the data.


title:
Note on Nariai and Tomita's and Starobinsky's cosmological solutions in
  the R^2 modified gravity

abstract:
  Cosmological solutions derived by Nariai and Tomita (1971) and by Starobinsky
(1980) are compared, and it is shown that the former derived de Sitter
expansion in the R^2 modified gravity (without cosmological constant) at the
earliest stage, and nine years later the latter derived the well-known
inflationary solution. Next the property of their simplified models is
described using the method of conformal transformations, and how the inflation
arises and the singularity is avoided is shown. Finally the initial and final
states of the inflation are discussed.


title:
Unrestricted Consumption under a Deterministic Wealth and an
  Ornstein-Uhlenbeck Process as a Discount Rate

abstract:
  We consider an individual or household endowed with an initial capital and an
income, modeled as a linear function of time. Assuming that the discount rate
evolves as an Ornstein-Uhlenbeck process, we target to find an unrestricted
consumption strategy such that the value of the expected discounted consumption
is maximized. Differently than in the case with restricted consumption rates,
we can determine the optimal strategy and the value function.


title:
Baryon Loading Efficiency and Particle Acceleration Efficiency of
  Relativistic Jets: Cases For Low Luminosity BL Lacs

abstract:
  Relativistic jets launched by supermassive black holes, so-called as active
galactic nuclei (AGNs), are known as the most energetic particle accelerators
in the universe. However, the baryon loading efficiency onto the jets from the
accretion flows and their particle acceleration efficiencies have been veiled
in mystery. With the latest data sets, we perform multi-wavelength spectral
analysis of quiescent spectra of 13 TeV gamma-ray detected
high-frequency-peaked BL Lacs (HBLs) following one-zone static
synchrotron-self-Compton (SSC) model. We determine the minimum, cooling break,
and maximum electron Lorentz factors following the diffusive shock acceleration
(DSA) theory. We find that HBLs have $P_B/P_e\sim6.3\times10^{-3}$ and the
radiative efficiency $\epsilon_{\rm rad,jet}\sim6.7\times10^{-4}$ where $P_B$
and $P_e$ is the Poynting and electron power, respectively. By assuming 10
leptons per one proton, the jet power relates to the black hole mass as $P_{\rm
jet}/L_{\rm Edd}\sim0.18$ where $P_{\rm jet}$ and $L_{\rm Edd}$ is the jet
power and the Eddington luminosity, respectively. Under our model assumptions,
we further find that HBLs have the jet production efficiency of $\eta_{\rm
jet}\sim1.5$ and the mass loading efficiency of $\xi_{\rm
jet}\gtrsim5\times10^{-2}$. We also investigate the particle acceleration
efficiency in the blazar zone by including the most recent Swift/BAT data. Our
samples ubiquitously have the particle acceleration efficiency of
$\eta_g\sim10^{4.5}$, which is inefficient to accelerate particles up to the
ultra-high-energy-cosmic-ray (UHECR) regime. This implies that the UHECR
acceleration sites should be other than the blazar zones of quiescent low power
AGN jets, if one assumes the one-zone SSC model based on the DSA theory.


title: Semantic Properties of Customer Sentiment in Tweets

abstract:
  An increasing number of people are using online social networking services
(SNSs), and a significant amount of information related to experiences in
consumption is shared in this new media form. Text mining is an emerging
technique for mining useful information from the web. We aim at discovering in
particular tweets semantic patterns in consumers' discussions on social media.
Specifically, the purposes of this study are twofold: 1) finding similarity and
dissimilarity between two sets of textual documents that include consumers'
sentiment polarities, two forms of positive vs. negative opinions and 2)
driving actual content from the textual data that has a semantic trend. The
considered tweets include consumers opinions on US retail companies (e.g.,
Amazon, Walmart). Cosine similarity and K-means clustering methods are used to
achieve the former goal, and Latent Dirichlet Allocation (LDA), a popular topic
modeling algorithm, is used for the latter purpose. This is the first study
which discover semantic properties of textual data in consumption context
beyond sentiment analysis. In addition to major findings, we apply LDA (Latent
Dirichlet Allocations) to the same data and drew latent topics that represent
consumers' positive opinions and negative opinions on social media.


title:
Position and Vector Detection of Blind Spot motion with the Horn-Schunck
  Optical Flow

abstract:
  The proposed method uses live image footage which, based on calculations of
pixel motion, decides whether or not an object is in the blind-spot. If found,
the driver is notified by a sensory light or noise built into the vehicle's
CPU. The new technology incorporates optical vectors and flow fields rather
than expensive radar-waves, creating cheaper detection systems that retain the
needed accuracy while adapting to the current processor speeds.


title:
Necessary and sufficient conditions for the strong local minimality of
  $C^1$ extremals on a class of non-smooth domains

abstract:
  Motivated by applications in materials science, a set of quasiconvexity at
the boundary conditions is introduced for domains that are locally
diffeomorphic to cones. These conditions are shown to be necessary for strong
local minimisers in the vectorial Calculus of Variations and a
quasiconvexity-based sufficiency theorem is established for ${\rm C}^1$
extremals defined on this class of non-smooth domains. The sufficiency result
presented here thus extends the seminal theorem by Grabovsky \& Mengesha
(2009), where smoothness assumptions are made on the boundary.


title: Hydrodynamics with spin in bacterial suspensions

abstract:
  We describe a new kind of self-propelling motion of bacteria based on the
cooperative action of rotating flagella on the surface of bacteria. Describing
the ensemble of rotating flagella in the framework of the hydrodynamics with
spin the reciprocal theorem of Stokesian hydrodynamics is generalized
accordingly. The velocity of the self-propulsion is expressed in terms of the
characteristics of the vector field of flagella orientation and it is shown
that unusually high velocities of \textit{Thiovulum majus} bacteria may be
explained by the cooperative action of the rotating flagella. The expressions
obtained enable us to estimate the torque created by the rotary motors of the
bacterium and show quantitative agreement with the existing experimental data.


title:
On Communication through a Gaussian Channel with an MMSE Disturbance
  Constraint

abstract:
  This paper considers a Gaussian channel with one transmitter and two
receivers. The goal is to maximize the communication rate at the
intended/primary receiver subject to a disturbance constraint at the
unintended/secondary receiver. The disturbance is measured in terms of minimum
mean square error (MMSE) of the interference that the transmission to the
primary receiver inflicts on the secondary receiver.
  The paper presents a new upper bound for the problem of maximizing the mutual
information subject to an MMSE constraint. The new bound holds for vector
inputs of any length and recovers a previously known limiting (when the length
of vector input tends to infinity) expression from the work of Bustin
$\textit{et al.}$ The key technical novelty is a new upper bound on the MMSE.
This bound allows one to bound the MMSE for all signal-to-noise ratio (SNR)
values $\textit{below}$ a certain SNR at which the MMSE is known (which
corresponds to the disturbance constraint). This bound complements the
`single-crossing point property' of the MMSE that upper bounds the MMSE for all
SNR values $\textit{above}$ a certain value at which the MMSE value is known.
The MMSE upper bound provides a refined characterization of the
phase-transition phenomenon which manifests, in the limit as the length of the
vector input goes to infinity, as a discontinuity of the MMSE for the problem
at hand.
  For vector inputs of size $n=1$, a matching lower bound, to within an
additive gap of order $O \left( \log \log \frac{1}{\sf MMSE} \right)$ (where
${\sf MMSE}$ is the disturbance constraint), is shown by means of the mixed
inputs technique recently introduced by Dytso $\textit{et al.}$


title: Holographic Schwinger effect with a deformed AdS background

abstract:
  In this paper, we consider a deformed AdS background and study effect of
deformation parameter on the pair production rate of the Schwinger effect. The
electrostatic potential is important for the pair production in the holographic
Schwinger effect. In this paper, we analyze the electrostatic potential in a
deformed AdS background and investigate the effect of deformation parameter
which may be useful to test of AdS/QCD. In the case of zero temperature we find
that larger value of the deformation parameter leads to a smaller value of
separation length of the test particles on the probe. Also we find a finite
maximum of separation length in presence of modification parameter.


title:
A Spatially-Varying Stochastic Differential Equation Model for Animal
  Movement

abstract:
  Animal movement exhibits complex behavior which can be influenced by
unobserved environmental conditions. We propose a model which allows for a
spatially-varying movement rate and spatially-varying drift through a
semiparametric potential surface and a separate motility surface. These
surfaces are embedded in a stochastic differential equation framework which
allows for complex animal movement patterns in space. The resulting model is
used to analyze the spatially-varying behavior of ants to provide insight into
the spatial structure of ant movement in the nest.


title: BanditRepair: Speculative Exploration of Runtime Patches

abstract:
  We propose, BanditRepair, a system that systematically explores and assesses
a set of possible runtime patches. The system is grounded on so-called bandit
algorithms, that are online machine learning algorithms, designed for
constantly balancing exploitation and exploration. BanditRepair's runtime
patches are based on modifying the execution state for repairing null
dereferences. BanditRepair constantly trades the ratio of automatically handled
failures for searching for new runtime patches and vice versa. We evaluate the
system with 16 null dereference field bugs, where BanditRepair identifies a
total of 8460 different runtime patches, which are composed of 1 up to 8
decisions (execution modifications) taken in a row. We are the first to finely
characterize the search space and the outcomes of runtime repair based on
execution modification.


title: Statistical inference in sparse high-dimensional additive models

abstract:
  In this paper we discuss the estimation of a nonparametric component $f_1$ of
a nonparametric additive model $Y=f_1(X_1) + ...+ f_q(X_q) + \epsilon$. We
allow the number $q$ of additive components to grow to infinity and we make
sparsity assumptions about the number of nonzero additive components. We
compare this estimation problem with that of estimating $f_1$ in the oracle
model $Z= f_1(X_1) + \epsilon$, for which the additive components
$f_2,\dots,f_q$ are known. We construct a two-step presmoothing-and-resmoothing
estimator of $f_1$ and state finite-sample bounds for the difference between
our estimator and some smoothing estimators $\hat f_1^{\text{(oracle)}}$ in the
oracle model. In an asymptotic setting these bounds can be used to show
asymptotic equivalence of our estimator and the oracle estimators; the paper
thus shows that, asymptotically, under strong enough sparsity conditions,
knowledge of $f_2,\dots,f_q$ has no effect on estimation accuracy. Our first
step is to estimate $f_1$ with an undersmoothed estimator based on
near-orthogonal projections with a group Lasso bias correction. We then
construct pseudo responses $\hat Y$ by evaluating a debiased modification of
our undersmoothed estimator of $f_1$ at the design points. In the second step
the smoothing method of the oracle estimator $\hat f_1^{\text{(oracle)}}$ is
applied to a nonparametric regression problem with responses $\hat Y$ and
covariates $X_1$. Our mathematical exposition centers primarily on establishing
properties of the presmoothing estimator. We present simulation results
demonstrating close-to-oracle performance of our estimator in practical
applications.


title: Freezing and melting equations for the $n$-6 Lennard-Jones systems

abstract:
  We generalize previous approach of Khrapak and Morfill [J. Chem. Phys. {\bf
134}, 094108 (2011)] to construct simple and sufficiently accurate freezing and
melting equations for the conventional Lennard-Jones (LJ) system to $n$-6 LJ
systems, using the accurate results for the triple points of these systems
published by Sousa {\it et al.} [J. Chem. Phys. {\bf 136}, 174502 (2012)].


title: On immersion formulas for soliton surfaces

abstract:
  This paper is devoted to a study of the connections between three different
analytic descriptions for the immersion functions of 2D-surfaces corresponding
to the following three types of symmetries: gauge symmetries of the linear
spectral problem, conformal transformations in the spectral parameter and
generalized symmetries of the associated integrable system. After a brief
exposition of the theory of soliton surfaces and of the main tool used to study
classical and generalized Lie symmetries, we derive the necessary and
sufficient conditions under which the immersion formulas associated with these
symmetries are linked by gauge transformations. We illustrate the theoretical
results by examples involving the sigma model.


title: Exploring the Use of RPAs as 5G Points of Presence

abstract:
  This paper presents an early exploration and preliminary results on the use
of Remotely Piloted Aircrafts (RPA) as 5G points of presence. The use of RPAs
in the 5G arena would enable a cost-effective deployment of functions over
mobile nodes that could be integrated on demand into the programmable and
unified 5G infrastructure, enhancing the capacity of the network to flexibly
adapt to the particular service requirements in a geographical area. As a first
step, we evaluate the feasibility and the cost, in terms of energy consumption,
of using virtualisation techniques over resource-constrained aerial vehicle
platforms, as a fundamental software technology in the evolution towards 5G. We
complement this evaluation presenting a proof-of-concept that considers the use
of these platforms to enable real-time 5G communications in emergency cases.


title:
Three-cluster breakup in deuteron-deuteron collisions: single-scattering
  approximation

abstract:
  We present results for the three-cluster breakup in deuteron-deuteron
collisions at 130 and 270 MeV deuteron beam energy. The breakup amplitude is
calculated using the first term in the Neumann series expansion of the
corresponding exact four-nucleon equations. In analogy with nucleon-deuteron
breakup where an equivalent approximation is compared with exact calculations,
we expect this single-scattering approximation to provide a rough estimation of
three-body breakup observables in quasifree configurations. We predict the
nucleon-deuteron and deuteron-deuteron three-cluster breakup cross sections to
be of a comparable size and thereby question the reliability of the recent
experimental data [A. Ramazani-Moghaddam-Arani, Ph.D. thesis, University of
Groningen, 2009; A. Ramazani-Moghaddam-Arani et al., EPJ Web of Conferences 3,
04012 (2010)] that is smaller by about three orders of magnitude. We also show
that an equivalent single-scattering approximation provides a reasonable
description of deuteron-deuteron elastic scattering at forward scattering
angles.


title: Observability through matrix-weighted graph

abstract:
  Observability of an array of identical LTI systems with incommensurable
output matrices is studied, where an array is called observable when
identically zero relative outputs imply synchronized solutions for the
individual systems. It is shown that the observability of an array is
equivalent to the connectivity of its interconnection graph, whose edges are
assigned matrix weights. The interconnection graph is studied by means of a
collection of simpler graphs, each of which is associated to an eigenvalue of
the system matrix of individual dynamics. It is reported that the
interconnection graph is connected if and only if no member of this collection
is disconnected. Moreover, to better understand the relative behavior of
distant units, pairwise observability which concerns with the synchronization
of a certain pair of individual systems in the array is studied. This milder
version of observability is shown to be closely related to certain connectivity
properties of the interconnection graph as well. Pairwise observability is also
analyzed using the circuit theoretic tool effective conductance. The
observability of a certain pair of units is proved to be equivalent to the
nonsingularity of the (matrix-valued) effective conductance between the
associated pair of nodes of a resistive network (with matrix-valued parameters)
whose node admittance matrix is the Laplacian of the array's interconnection
graph.


title: Measurements of ion mobility in argon and neon based gas mixtures

abstract:
  As gaseous detectors are operated at high rates of primary ionisation, ions
created in the detector have a considerable impact on the performance of the
detector. The upgraded ALICE Time Projection Chamber (TPC) will operate during
LHC Run$\,3$ with a substantial space charge density of positive ions in the
drift volume. In order to properly simulate such space charges, knowledge of
the ion mobility $K$ is necessary.
  To this end, a small gaseous detector was constructed and the ion mobility of
various gas mixtures was measured. To validate the corresponding signal
analysis, simulations were performed.
  Results are shown for several argon and neon based mixtures with different
$\textrm{CO}_2$ fractions. A decrease of $K$ was measured for increasing water
content.


title: A geometric description of the homology of surface bundles

abstract:
  In the present note we describe geometrically the homology classes in the
total space of a surface bundle over a surface in terms of the holonomy map. We
treat the cases where the base surface is closed or has one boundary component.
  We replace the wrong theorem of the previous version by some observations on
the homology of surface bundles and explain why our previous strategy failed.


title:
Electron interaction with the angular momentum of the electromagnetic
  field

abstract:
  We give a simple derivation and explanation of a recently proposed new
relativistic interaction between the electron and the angular momentum of the
electromagnetic field in quantum electrodynamics (QED). Our derivation is based
on the work of Moller, who pointed out that, in special relativity, a particle
with spin must always have a finite extension. We generalize Mollers classical
result to the quantum regime and show that it leads to a new contribution to
the energy, which is the special relativistic interaction term. In addition, we
show that all spin terms arising from the Dirac equation may be obtained by
this method.


title: Inferring Uncertain Trajectories from Partial Observations

abstract:
  The explosion in the availability of GPS-enabled devices has resulted in an
abundance of trajectory data. In reality, however, majority of these
trajectories are collected at a low sampling rate and only provide partial
observations on their actually traversed routes. Consequently, they are mired
with uncertainty. In this paper, we develop a technique called InferTra to
infer uncertain trajectories from network-constrained partial observations.
Rather than predicting the most likely route, the inferred uncertain trajectory
takes the form of an edge-weighted graph and summarizes all probable routes in
a holistic manner. For trajectory inference, InferTra employs Gibbs sampling by
learning a Network Mobility Model (NMM) from a database of historical
trajectories. Extensive experiments on real trajectory databases show that the
graph-based approach of InferTra is up to 50% more accurate, 20 times faster,
and immensely more versatile than state-of-the-art techniques.


title:
Plasmon drag effect in profile-modulated gold films. Theory and
  experiment

abstract:
  Plasmon drag effect is studied theoretically and experimentally in gold films
with a sine-wave height profile. Numerical simulations based on the modified
electromagnetic momentum loss approach are shown to correctly describe the
photoinduced voltage associated with propagating surface plasmon polaritons.
Direct proportionality of energy and momentum transfer in interactions of
plasmons and free electrons in metal is proven to be valid for surfaces with
relatively low height modulation amplitudes. The effect is also discussed in
frames of an equivalent circuit model, which can provide qualitative
description for surfaces with random roughness.


title:
Giant Magnetoelectric coupling in Single Phase
  Pb(Zr0.20Ti0.80)0.70Pd0.30O3-{\delta} Multiferroics

abstract:
  During the last fifteen years, multiferroic (MF) research communities have
been searching for an alternative room temperature MF material with large
magnetoelectric (ME) coupling for possible applications in high density
electronic components, low heat dissipation memory and logic devices. We have
studied Pb(Zr0.20Ti0.80)0.70Pd0.30O3-{\delta} (PZTP30) system with an unusually
large (30%) palladium occupancy in B site of PZT. This material exhibited a
giant ME coupling coefficient ~0.36 mV/cm.Oe. Interestingly, this is the first
time any room temperature single phase compound that showed ME trends, and
magnitude similar to those in the well established mechanical strain-mediated
ferroelectric and ferromagnetic composites; the latter ones are already in the
commercial stage as nT/pT magnetic field sensors due to their large ME values.
The presence of Pd in PZTP30 has been confirmed by XPS and XRF studies and
assigned with related binding energies of Pd+2 and Pd+4 ions as 336.37 eV,
342.9 eV, and 337.53 eV, 343.43 eV, respectively, which may be the origin of
room temperature magnetism in Pd substituted PZT ceramics. A sharp first order
ferroelectric phase transition was observed at ~569 K (+/-5 K) that is
confirmed from dielectric, Raman, and thermal analysis. Both ferromagnetic and
ferroelectric orderings with large ME coupling were found above room
temperature, a significant step forward in the development of single phase ME
material with enhanced functionalities.


title:
Local Histogram Matching for Efficient Optical Flow Computation Applied
  to Velocity Estimation on Pocket Drones

abstract:
  Autonomous flight of pocket drones is challenging due to the severe
limitations on on-board energy, sensing, and processing power. However, tiny
drones have great potential as their small size allows maneuvering through
narrow spaces while their small weight provides significant safety advantages.
This paper presents a computationally efficient algorithm for determining
optical flow, which can be run on an STM32F4 microprocessor (168 MHz) of a 4
gram stereo-camera. The optical flow algorithm is based on edge histograms. We
propose a matching scheme to determine local optical flow. Moreover, the method
allows for sub-pixel flow determination based on time horizon adaptation. We
demonstrate velocity measurements in flight and use it within a velocity
control-loop on a pocket drone.


title:
How speed of sound measurements could bring constraints on the
  composition of Titan's seas

abstract:
  The hydrocarbons seas of Titan, discovered by Cassini/Huygens mission are
among the most mysterious and interesting features of this moon. In the future,
a possible dedicated planetary probe, will certainly measure the speed of sound
in this cryogenic liquid, as it was planned in the case of a Huygens landing
into a sea. Previous theoretical studies of such acoustic measurements were
based on rather simple models, leading in some cases to unphysical situations.
Employed in a vast body of chemical engineering works, the state of the art
PC-SAFT model has been recently introduced in studies aimed at Titan. Here, I
revisit the issue of the speed of sound in Titan's liquids, in the light of
this theory. I describe, in detail, the derivation of the speed of sound from
the chosen equation of state and the potential limitations of the approach. To
make estimations of the composition of a ternary liquid mixture N2:CH4:C2H6
from speed of sound measurements an original inversion algorithm is proposed.
It is shown that 50 measures between 90 K and 100 K are enough to ensure an
accuracy of the derived compositions better than 10%. The influence of the
possible presence of propane is also investigated.


title: Recursive Neural Language Architecture for Tag Prediction

abstract:
  We consider the problem of learning distributed representations for tags from
their associated content for the task of tag recommendation. Considering
tagging information is usually very sparse, effective learning from content and
tag association is very crucial and challenging task. Recently, various neural
representation learning models such as WSABIE and its variants show promising
performance, mainly due to compact feature representations learned in a
semantic space. However, their capacity is limited by a linear compositional
approach for representing tags as sum of equal parts and hurt their
performance. In this work, we propose a neural feedback relevance model for
learning tag representations with weighted feature representations. Our
experiments on two widely used datasets show significant improvement for
quality of recommendations over various baselines.


title:
A chromaticity-brightness model for color images denoising in a Meyer's
  "u+v" framework

abstract:
  A variational model for imaging segmentation and denoising color images is
proposed. The model combines Meyer's "u+v" decomposition with a
chromaticity-brightness framework and is expressed by a minimization of energy
integral functionals depending on a small parameter $\epsi>0$. The asymptotic
behavior as $\epsi\to0^+$ is characterized, and convergence of infima, almost
minimizers, and energies are established. In particular, an integral
representation of the lower semicontinuous envelope, with respect to the
$L^1$-norm, of functionals with linear growth and defined for maps taking
values on a certain compact manifold is provided. This study escapes the realm
of previous results since the underlying manifold has boundary, and the
integrand and its recession function fail to satisfy hypotheses commonly
assumed in the literature. The main tools are $\Gamma$-convergence and
relaxation techniques.


title: Nonlinear waves in adhesive strings

abstract:
  We study a 1D semilinear wave equation modeling the dynamic of an elastic
string interacting with a rigid substrate through an adhesive layer. The
constitutive law of the adhesive material is assumed elastic up to a finite
critical state, beyond such a value the stress discontinuously drops to zero.
Therefore the semilinear equation is characterized by a source term presenting
jump discontinuity. Well-posedness of the initial boundary value problem of
Neumann type, as well as qualitative properties of the solutions are studied
and the evolution of different initial conditions are numerically investigated.


title:
Efficiency at maximum power and efficiency fluctuations in a linear
  Brownian heat engine model

abstract:
  We investigate stochastic thermodynamics of a two-particles Langevin system.
Each particle is in contact with a heat bath at different temperatures $T_1$
and $T_2~(<T_1)$, respectively. Particles are trapped by a harmonic potential
and driven by a linear external force. The system can act as an autonomous heat
engine performing work against the external driving force. Linearity of the
system enables us to examine thermodynamic properties of the engine
analytically. We find that the efficiency of the engine at maximum power
$\eta_{MP}$ is given by $\eta_{MP} = 1-\sqrt{T_2/T_1}$. This universal form has
been known as a characteristic of endoreversible heat engines. Our result
extends the universal behavior of $\eta_{MP}$ to non-endoreversible engines. We
also obtain the large deviation function of the probability distribution for
the stochastic efficiency in the overdamped limit. The large deviation function
takes the minimum value at mean efficiency $\eta = \bar{\eta}$ and increases
monotonically until it reaches plateaus when $\eta \leq \eta_L$ and $\eta \geq
\eta_R$ with model dependent parameters $\eta_{R,L}$. It has been known for
heat engines with a finite number of microscopic configurations with
time-symmetric protocol that the probability of achieving the Carnot efficiency
is minimum. Our result reveals that the least likeliness of the Carnot
efficiency is not the generic property of heat engines.


title: Decoding and File Transfer Delay Balancing in Network Coding Broadcast

abstract:
  Network Coding is a packet encoding technique which has recently been shown
to improve network performance (by reducing delays and increasing throughput)
in broadcast and multicast communications. The cost for such an improvement
comes in the form of increased decoding complexity (and thus delay) at the
receivers end. Before delivering the file to higher layers, the receiver should
first decode those packets. In our work we consider the broadcast transmission
of a large file to N wireless users. The file is segmented into a number of
blocks (each containing K packets - the Coding Window Size). The packets of
each block are encoded using Random Linear Network Coding (RLNC).We obtain the
minimum coding window size so that the completion time of the file transmission
is upper bounded by a used defined delay constraint.


title:
The Hubble Space Telescope UV Legacy Survey of Galactic Globular
  Clusters. VII. Implications from the Nearly Universal Nature of Horizontal
  Branch Discontinuities

abstract:
  The UV-initiative Hubble Space Telescope Treasury survey of Galactic globular
clusters provides a new window into the phenomena that shape the morphological
features of the horizontal branch (HB). Using this large and homogeneous
catalog of UV and blue photometry, we demonstrate that the HB exhibits
discontinuities that are remarkably consistent in color (effective
temperature). This consistency is apparent even among some of the most massive
clusters hosting multiple distinct sub-populations (such as NGC 2808, omega
Cen, and NGC 6715), demonstrating that these phenomena are primarily driven by
atmospheric physics that is independent of the underlying population
properties. However, inconsistencies arise in the metal-rich clusters NGC 6388
and NGC 6441, where the discontinuity within the blue HB (BHB) distribution
shifts ~1,000 K to 2,000 K hotter. We demonstrate that this shift is likely due
to a large helium enhancement in the BHB stars of these clusters, which in turn
affects the surface convection and evolution of such stars. Our survey also
increases the number of Galactic globular clusters known to host blue-hook
stars (also known as late hot flashers) from 6 to 23 clusters. These clusters
are biased toward the bright end of the globular cluster luminosity function,
confirming that blue-hook stars tend to form in the most massive clusters with
significant self-enrichment.


title:
Voltage induced switching dynamics of a coupled spin pair in a molecular
  junction

abstract:
  Molecular spintronics is made possible by the coupling between electronic
configuration and magnetic po- larization of the molecules. For control and
application of the individual molecular states it is necessary to both read and
write their spin states. Conventionally, this is achieved by means of external
magnetic fields or ferromagnetic contacts, which may change the intentional
spin state and may present additional challenges when downsizing devices. Here,
we predict that coupling magnetic molecules together opens up possibilities for
all electrical control of both the molecular spin states as well as the current
flow through the system. Tuning between the regimes of ferromagnetic and
anti-ferromagnetic exchange interaction, the current can be, at least, an order
of magnitude enhanced or reduced. The effect is susceptible to the tunnel
coupling and molecular level alignment which can be used to achieve current
rectification.


title:
A Quaternion Frequency and Phasor Estimator for Three-Phase Power
  Distribution Networks

abstract:
  For the first time quaternions have been used for real-time frequency
estimation, where the multi-dimensional nature of quaternions allows for the
full characterization of three-phase power systems. This is achieved through
the use of quaternions to provide a unified framework for incorporating voltage
measurements from all the phases of a three-phase system and then employing the
recently introduced HR-calculus to derive a state space estimator based on the
quaternion extended Kalman filter (QEKF). The components of the state space
vector are designed such that they can be deployed for adaptive estimation of
the system phasors. Finally, the proposed algorithm is validated through
simulations using both synthetic and real-world data, which indicate that the
developed quaternion frequency estimator can outperform its complex-valued
counterparts.


title: A Users' Guide to Infra-nilmanifolds and Almost-Bieberbach groups

abstract:
  The aim of this text is to provide a clear description of the theory of
Infra-nilmanifolds and their fundamental groups, the almost-Bieberbach groups.
For most of the proofs of the results, we refer to the literature.
Nevertheless, at certain places we offer a somewhat different and new approach
and in these cases we provide full proofs. We have tried to keep the
prerequisites as minimal as possible. We also provide completely worked out
examples, with explicit computations.


title:
The Mechanics of Spacetime - A Solid Mechanics Perspective on the Theory
  of General Relativity

abstract:
  We present an elastic constitutive model of gravity where we identify
physical space with the mid-hypersurface of an elastic hyperplate called the
"cosmic fabric" and spacetime with the fabric's world volume. Using a
Lagrangian formulation, we show that the fabric's behavior as derived from
Hooke's Law is analogous to that of spacetime per the Field Equations of
General Relativity. The study is conducted in the limit of small strains, or
analogously, in the limit of weak and nearly static gravitational fields. The
Fabric's Lagrangian outside of inclusions is shown to have the same form as the
Einstein-Hilbert Lagrangian for free space. Properties of the fabric such as
strain, stress, vibrations, and elastic moduli are related to properties of
gravity and space, such as the gravitational potential, gravitational
acceleration, gravitational waves, and the energy density of free space. By
introducing a mechanical analogy of General Relativity, we enable the
application of Solid Mechanics tools to address problems in Cosmology.


title: Spectral property of self-affine measures on ${\mathbb R}^n$

abstract:
  We study spectral properties of the self-affine measure $\mu_{M,\mathcal
{D}}$ generated by an expanding integer matrix $M\in M_n(\mathbb{Z})$ and a
consecutive collinear digit set $\mathcal {D}=\{0,1,\dots,q-1\}v$ where $v\in
\mathbb{Z}^n\setminus\{0\}$ and $q\ge 2$ is an integer. Some sufficient
conditions for $\mu_{M,\mathcal {D}}$ to be a spectral measure or to have
infinitely many orthogonal exponentials are given. Moreover, for some special
cases, we can obtain a necessary and sufficient condition on the spectrality of
$\mu_{M,\mathcal {D}}$. Our study generalizes the one dimensional results
proved by Dai, {\it et al.} (\cite{Dai-He-Lai_2013, Dai-He-Lau_2014}).


title:
Generating Functions for Products of Special Laguerre 2D and Hermite 2D
  Polynomials

abstract:
  The bilinear generating function for products of two Laguerre 2D polynomials
Lm;n(z; z0) with different arguments is calculated. It corresponds to the
formula of Mehler for the generating function of products of two Hermite
polynomials. Furthermore, the generating function for mixed products of
Laguerre 2D and Hermite 2D polynomials and for products of two Hermite 2D
polynomials is calculated. A set of infinite sums over products of two Laguerre
2D polynomials as intermediate step to the generating function for products of
Laguerre 2D polynomials is evaluated but these sums possess also proper
importance for calculations with Laguerre polynomials. With the technique of
SU(1; 1) operator disentanglement some operator identities are derived in an
appendix. They allow to calculate convolutions of Gaussian functions combined
with polynomials in one- and two-dimensional case and are applied to evaluate
the discussed generating functions. Keywords: Laguerre and Hermite polynomials,
Laguerre 2D polynomials, Jacobi polynomials, Mehler formula, SU(1; 1) operator
disentanglement, Gaussian convolutions.


title: Maximizers for the Stein-Tomas inequality

abstract:
  We give a necessary and sufficient condition for the precompactness of all
optimizing sequences for the Stein-Tomas inequality. In particular, if a
well-known conjecture about the optimal constant in the Strichartz inequality
is true, we obtain the existence of an optimizer in the Stein-Tomas inequality.
Our result is valid in any dimension.


title: General pairing mechanisms in the BCS-theory of superconductivity

abstract:
  Starting from the linearized BdG-equation we make the simple observation that
pairing can occur between particles with total momenta different from zero,
e.g., with equal momentum and opposite spin, in cases of an effective
interaction acting in the center-of-mass coordinates.


title: Energy Scaling of Targeted Optimal Control of Complex Networks

abstract:
  Recently it has been shown that the control energy required to control a
dynamical complex network is prohibitively large when there are only a few
control inputs. Most methods to reduce the control energy have focused on
where, in the network, to place additional control inputs. Here, in contrast,
we show that by controlling the states of a subset of the nodes of a network,
rather than the state of every node, while holding the number of control
signals constant, the required energy to control a portion of the network can
be reduced substantially. The energy requirements exponentially decay with the
number of target nodes, suggesting that large networks can be controlled by a
relatively small number of inputs as long as the target set is appropriately
sized. We validate our conclusions in model and real networks to arrive at an
energy scaling law to better design control objectives regardless of system
size, energy restrictions, state restrictions, input node choices and target
node choices.


title: Normal Crossings Degenerations of Symplectic Manifolds

abstract:
  We use local Hamiltonian torus actions to degenerate a symplectic manifold to
a normal crossings symplectic variety in a smooth one-parameter family. This
construction, motivated in part by the Gross-Siebert and B. Parker's programs,
contains a multifold version of the usual (two-fold) symplectic cut
construction and in particular splits a symplectic manifold into several
symplectic manifolds containing normal crossings symplectic divisors with
shared irreducible components in one step.


title: The Betti numbers of regular Hessenberg varieties are palindromic

abstract:
  Recently Brosnan and Chow have proven a conjecture of Shareshian and Wachs
describing a representation of the symmetric group on the cohomology of regular
semisimple Hessenberg varieties for $GL_n(\mathbb{C})$. A key component of
their argument is that the Betti numbers of regular Hessenberg varieties for
$GL_n(\mathbb{C})$ are palindromic. In this paper, we extend this result to all
reductive algebraic groups, proving that the Betti numbers of regular
Hessenberg varieties are palindromic.


title:
Fe Nanoclusters on the Ge(001) Surface Studied by Scanning Tunneling
  Microscopy, Density Functional Theory Calculations and X-Ray Magnetic
  Circular Dichroism

abstract:
  The growth of Fe nanoclusters on the Ge(001) surface has been studied using
lowtemperature scanning tunnelling microscopy (STM) and density functional
theory (DFT) calculations. STM results indicate that Fe nucleates on the
Ge(001) surface, forming wellordered nanoclusters of uniform size. Depending on
the preparation conditions, two types of nanoclusters were observed having
either four or sixteen Fe atoms within a nanocluster. The results were
confirmed by DFT calculations. Annealing the nanoclusters at 420 K leads to the
formation of nanorow structures, due to cluster mobility at such temperature.
The Fe nanoclusters and nanorow structures formed on the Ge(001) surface show a
superparamagnetic behaviour as measured by X-ray magnetic circular dichroism.


title: A formula for the convergents of a continued fraction of Ramanujan

abstract:
  In Entry 16, Chapter 16 of his notebooks, Ramanujan himself gave a formula
for the convergents of the famous Rogers-Ramanujan continued fraction. We
provide a similar formula for the convergents of a more general continued
fraction, namely Entry 15 of Chapter 16.


title: Quasi-particle interactions in frustrated Heisenberg chains

abstract:
  Interactions between elementary excitations in quasi-one dimensional
antiferromagnets are of experimental relevance and their quantitative
theoretical treatment has been a theoretical challenge for many years. Using
matrix product states, one can explicitly determine the wavefunctions of the
one- and two-particle excitations, and, consequently, the contributions to
dynamical correlations. We apply this framework to the (non integrable)
frustrated dimerized spin-1/2 chain, a model for generic spin-Peierls systems,
where low-energy quasi-particle excitations are bound states of topological
solitons. The spin structure factor involving two quasi-particle scattering
states is obtained in the thermodynamic limit with full momentum and frequency
resolution. This allows very subtle features in the two-particle spectral
function to be revealed which, we argue, could be seen, e.g., in inelastic
neutron scattering of spin-Peierls compounds under a change of the external
pressure.


title: Quantum walks with a one-dimensional coin

abstract:
  Quantum walks (QWs) describe particles evolving coherently on a lattice. The
internal degree of freedom corresponds to a Hilbert space, called coin system.
We consider QWs on Cayley graphs of some group $G$. In the literature,
investigations concerning infinite $G$ have been focused on graphs
corresponding to $G=\mathbb{Z}^d$ with coin system of dimension 2, whereas for
one-dimensional coin (so called scalar QWs) only the case of finite $G$ has
been studied. Here we prove that the evolution of a scalar QW with $G$ infinite
Abelian is trivial, providing a thorough classification of this kind of walks.
Then we consider the infinite dihedral group $D_\infty$, that is the unique
non-Abelian group $G$ containing a subgroup $H\cong\mathbb{Z}$ with two cosets.
We characterize the class of QWs on the Cayley graphs of $D_\infty$ and, via a
coarse-graining technique, we show that it coincides with the class of
spinorial walks on $\mathbb{Z}$ which satisfies parity symmetry. This class of
QWs includes the Weyl and the Dirac QWs. Remarkably, there exist also spinorial
walks that are not coarse-graining of a scalar QW, such as the Hadamard walk.


title: Hybridized Tetraquarks

abstract:
  We propose a new interpretation of the neutral and charged X, Z exotic hadron
resonances. Hybridized-tetraquarks are neither purely compact tetraquark states
nor bound or loosely bound molecules. The latter would require a negative or
zero binding energy whose counterpart in h-tetraquarks is a positive quantity.
The formation mechanism of this new class of hadrons is inspired by that of
Feshbach metastable states in atomic physics. The recent claim of an exotic
resonance in the Bs pi+- channel by the D0 collaboration and the negative
result presented subsequently by the LHCb collaboration are understood in this
scheme, together with a considerable portion of available data on X, Z
particles. Considerations on a state with the same quantum numbers as the
X(5568) are also made.


title:
Estimating Cross-validatory Predictive P-values with Integrated
  Importance Sampling for Disease Mapping Models

abstract:
  An important statistical task in disease mapping problems is to identify
divergent regions with unusually high or low risk of disease. Leave-one-out
cross-validatory (LOOCV) model assessment is the gold standard for estimating
predictive p-values that can flag such divergent regions. However, actual LOOCV
is time-consuming because one needs to rerun a Markov chain Monte Carlo
analysis for each posterior distribution in which an observation is held out as
a test case. This paper introduces a new method, called integrated importance
sampling (iIS), for estimating LOOCV predictive p-values with only Markov chain
samples drawn from the posterior based on a full data set. The key step in iIS
is that we integrate away the latent variables associated the test observation
with respect to their conditional distribution \textit{without} reference to
the actual observation. By following the general theory for importance
sampling, the formula used by iIS can be proved to be equivalent to the LOOCV
predictive p-value. We compare iIS and other three existing methods in the
literature with two disease mapping datasets. Our empirical results show that
the predictive p-values estimated with iIS are almost identical to the
predictive p-values estimated with actual LOOCV, and outperform those given by
the existing three methods, namely, the posterior predictive checking, the
ordinary importance sampling, and the ghosting method by Marshall and
Spiegelhalter (2003).


title:
First demonstration of VUV-photon detection in liquid xenon with THGEM
  and GEM-based Liquid Hole Multipliers

abstract:
  The bubble-assisted Liquid Hole-Multiplier (LHM) is a recently-introduced
detection concept for noble-liquid time projection chambers. In this "local
dual-phase" detection element, a gas bubble is supported underneath a
perforated electrode (e.g., Thick Gas Electron Multiplier - THGEM, or Gas
Electron Multiplier - GEM). Electrons drifting through the holes induce large
electroluminescence signals as they pass into the bubble. In this work we
report on recent results of THGEM and GEM electrodes coated with cesium iodide
and immersed in liquid xenon, allowing - for the first time - the detection of
primary VUV scintillation photons in addition to ionization electrons using
LHMs.


title: Composite gauge-bosons made of fermions

abstract:
  We construct a class of Abelian and non-Abelian local gauge theories that
consist only of matter fields of fermions. The Lagrangian is compact and local
without containing an auxiliary vector field nor a subsidiary condition on the
matter fields. Because of the special structure, this Lagrangian can be
extended to non-Abelian gauge symmetry only in the case of SU(2) doublet matter
fields. We carry out explicit dynamical computation in the leading 1/N order to
show that massless spin-one bound states appear with the correct gauge
coupling. Our diagram calculation exposes the dynamical features that cannot be
explored in the formal auxiliary vector-field trick. For instance, it shows
that the s-wave fermion-antifermion interaction alone cannot form the bound
gauge-bosons; the fermion-antifermion pairs must couple to the d-wave state
too. One feature common to our class of Lagrangian is that the Noether current
does not exist. Therefore it evades possible conflict with the no-go theorem of
Weinberg and Witten on formation of the non-Abelian gauge bosons.


title:
Promoting Efficient Infrastructure Competition through Vectoring and
  Enlarged DSL Bandwidth

abstract:
  The most effective way to promote Next Generation Access coverage and
ultra-broadband penetration is through infrastructure competition.


title:
Leptoquark patterns unifying neutrino masses, flavor anomalies, and the
  diphoton excess

abstract:
  Vector leptoquarks provide an elegant solution to a series of anomalies and
at the same time generate naturally light neutrino masses through their mixing
with the standard model Higgs boson. We present a simple Froggatt-Nielsen model
to accommodate the B physics anomalies $R_K$ and $R_D$, neutrino masses, and
the $750$ GeV diphoton excess in one cohesive framework adding only two vector
leptoquarks and two singlet scalar fields to the standard model field content.


title:
First Results from the La Silla-QUEST Supernova Survey and the Carnegie
  Supernova Project

abstract:
  The LaSilla/QUEST Variability Survey (LSQ) and the Carnegie Supernova Project
(CSP II) are collaborating to discover and obtain photometric light curves for
a large sample of low redshift (z < 0.1) Type Ia supernovae. The supernovae are
discovered in the LSQ survey using the 1 m ESO Schmidt telescope at the La
Silla Observatory with the 10 square degree QUEST camera. The follow-up
photometric observations are carried out using the 1 m Swope telescope and the
2.5 m du Pont telescopes at the Las Campanas Observatory. This paper describes
the survey, discusses the methods of analyzing the data and presents the light
curves for the first 31 Type Ia supernovae obtained in the survey. The SALT 2.4
supernova light curve fitter was used to analyze the photometric data, and the
Hubble diagram for this first sample is presented. The measurement errors for
these supernovae averaged 4%, and their intrinsic spread was 14%.


title:
Trapping planets in an evolving protoplanetary disk: preferred time,
  locations and planet mass

abstract:
  Planet traps are necessary to prevent forming planets from falling onto their
host star by type I migration. Surface mass density and temperature gradient
irregularities favor the apparition of traps and deserts. Such features are
found at the dust sublimation lines and heat transition barriers. We study how
planets may remain trapped or escape as they grow and as the disk evolves. We
model the temporal viscous evolution of a protoplanetary disk by coupling its
dynamics, thermodynamics, geometry and composition. The resulting mid-plane
density and temperature profiles allow the modeling of the interactions of such
an evolving disk with potential planets, even before the steady state is
reached. We follow the viscous evolution of a MMSN and compute the Lindblad and
corotation torques that such a disk would exert on potential planets of various
masses located within the planetary formation region. We determine the position
of planet traps and deserts in relationship with the sublimation lines,
shadowed regions and heat transition barriers. Planets that are a few tens of
Earth masses can be trapped at the sublimation lines until they reach a certain
mass while planets more massive than 100ME can only be trapped permanently at
the heat transition barriers. Coupling a bimodal planetary migration model with
a self-consistent evolved disk, we were able to distinguish several potential
planet populations after 5 million years of evolution: two populations of giant
planets that could stay trapped around 5.5 and 9 au and possibly open gaps,
some super-Earths trapped around 5 and 7.5 au and a population of close-in
super-Earths trapped inside 1 au. The traps corresponding to the last group
could help validating the in-situ formation scenarios of the observed close-in
super-Earths.


title:
A Temporal Analysis Indicates a Mildly Relativistic Compact Jet in
  GRS~1915+105

abstract:
  Most of our knowledge of the radio morphology and kinematics of X-ray binary
partially synchrotron self-absorbed compact jets (hereafter compact jets) is
based on the observations of GRS~1915+105 which has the most prominent compact
jet. Yet, the compact jet bulk velocity, $v$, is poorly constrained in the
literature, $0.07 < v/c < 0.98$. In spite of this uncertainty, compact jets are
often unified with relativistic jets in active galactic nuclei. We have
estimated $v$ as part of a temporal analysis of GRS~1915+105 jets in "high
plateau states" (HPS). We define the HPS as a state showing a hard X-ray
spectrum and low level of long-term ($>10$s) X-ray activity associated with 15
GHz flux density $>70$ mJy for $>7$ consecutive days. The radio emission is
associated with compact jet emission. Two HPS were monitored at 15 GHz during
their termination with e-folding times of 3.8 hrs and 8.6 hrs. We combine this
time scale with the scale of spatial variation of the linear source of a VLBA
image preceding the fade of one of these HPS in order to estimate the jet
speed. Our assumption that the reduction in radio emissivity propagates as an
approximate discontinuity down the HPS jet (leaving a weak jet in its wake)
indicates $0.17 <v/c< 0.43$. This agrees closely with the only other existing
$v$ estimates that are derived directly from radio images, jet asymmetry
produced by Doppler enhancement.


title:
Disorder-induced density of states on the surface of a spherical
  topological insulator

abstract:
  We consider a topological insulator (TI) of spherical geometry and
numerically investigate the influence of disorder on the density of surface
states. To the clean Hamiltonian we add a surface disorder potential of the
most general hermitian form, $V = V^0(\theta,\phi) + {\bf V}(\theta,\phi) \cdot
{\bf \sigma}$. We expand these four disorder functions in spherical harmonics
and draw the expansion coefficients randomly from a four-dimensional, zero-mean
gaussian distribution. Different strengths and classes of disorder are realized
by specifying the $4 \times 4$ covariance matrix. For each instantiation of the
disorder, we solve for the energy spectrum via exact diagonalization. Then we
compute the disorder-averaged density of states, $\rho(E)$, by averaging over
200,000 different instantiations. Disorder broadens the Landau-level delta
functions of the clean density of states into peaks that decay and merge
together. If the spin-dependent term is dominant, these peaks split due to the
breaking of the degeneracy between time-reversed partner states. Increasing
disorder strength pushes states closer and closer to zero energy (the Dirac
point), resulting in a low-energy density of states that becomes nonzero for
sufficient disorder, typically approaching an energy-independent saturation
value, for most classes of disorder. But for purely spin-dependent disorder
with ${\bf V}$ either entirely out-of-surface or entirely in-surface, we
identify intriguing disorder-induced features in the vicinity of the Dirac
point. In the out-of-surface case, a new peak emerges at zero energy. In the
in-surface case, we see a symmetry-protected zero at zero energy, with
$\rho(E)$ increasing linearly toward nonzero-energy peaks. These striking
features are explained in terms of the breaking (or not) of two chiral
symmetries of the clean Hamiltonian.


title:
Tuning dissociation using isoelectronically doped graphene and hexagonal
  boron nitride: water and other small molecules

abstract:
  Novel uses for 2-dimensional materials like graphene and hexagonal boron
nitride (h-BN) are being frequently discovered especially for membrane and
catalysis applications. Still however, a great deal remains to be understood
about the interaction of environmentally and industrially elevant molecules
such as water with these materials. Taking inspiration from advances in
hybridising graphene and h-BN, we explore using density functional theory, the
dissociation of water, hydrogen, methane, and methanol on graphene, h-BN, and
their isoelectronic doped counterparts: BN doped graphene and C doped h-BN. We
find that doped surfaces are considerably more reactive than their pristine
counterparts and by comparing the reactivity of several small molecules we
develop a general framework for dissociative adsorption. From this a
particularly attractive consequence of isoelectronic doping emerges: substrates
can be doped to enhance their reactivity specifically towards either polar or
non-polar adsorbates. As such, these substrates are potentially viable
candidates for selective catalysts and membranes, with the implication that a
range of tuneable materials can be designed.


title: Basic circuit compilation techniques for an ion-trap quantum machine

abstract:
  We study the problem of compilation of quantum algorithms into optimized
physical-level circuits executable in a quantum information processing (QIP)
experiment based on trapped atomic ions. We report a complete strategy:
starting with an algorithm in the form of a quantum computer program, we
compile it into a high-level logical circuit that goes through multiple stages
of decomposition into progressively lower-level circuits until we reach the
physical execution-level specification. We skip the fault-tolerance layer, as
it is not within the scope of this work. The different stages are structured so
as to best assist with the overall optimization while taking into account
numerous optimization criteria, including minimizing the number of expensive
two-qubit gates, minimizing the number of less expensive single-qubit gates,
optimizing the runtime, minimizing the overall circuit error, and optimizing
classical control sequences. Our approach allows a trade-off between circuit
runtime and quantum error, as well as to accommodate future changes in the
optimization criteria that may likely arise as a result of the anticipated
improvements in the physical-level control of the experiment.