title:
Band offset of GaAs/AlxGa1-xAs heterojunctions from atomistic first
  principles

abstract:
  Using an atomistic first principles approach, we investigate the band offset
of the GaAs/AlxGa1-xAs heterojunctions for the entire range of the Al doping
concentration 0<x<=1. We apply the coherent potential approach to handle the
configuration average of Al doping and a recently proposed semi-local exchange
potential to accurately determine the band gaps of the materials. The
calculated band structures of the GaAs, AlAs crystals and band gaps of the
GaAs/AlxGa1-xAs alloys, are in very good agreement with the experimental
results. We predict that valence band offset of the GaAs/AlxGa1-xAs
heterojunction scales with the Al concentration x in a linear fashion as
VBO(x)~0.587 x, and the conduction band offset scales with x in a nonlinear
fashion. Quantitative comparisons to the corresponding experimental data are
made.


title:
An ARPES Study of the Electronic Structure of the Quantum Spin Liquid
  EtMe3Sb[Pd(dmit)2]2

abstract:
  The electronic structure of a quantum spin liquid compound,
EtMe3Sb[Pd(dmit)2]2, has been studied with angle-resolved photoemission
spectroscopy, together with two other Pd(dmit)2 salts in the valence bond solid
or antiferromagnetic state. We have resolved several bands that have negligible
dispersions and fit well to the calculated energy levels of an isolated
[Pd(dmit)2]2 dimer. EtMe3Sb[Pd(dmit)2]2 being a Mott insulator, its lower
Hubbard band is identified, and there is a small gap of ~ 50 meV between this
band and the chemical potential. Moreover, the spectral features exhibit
polaronic behavior with anomalously broad linewidth. Compared with existing
theories, our results suggest that strong electron-boson interactions, together
with smaller hopping and on-site Coulomb interaction terms have to be
considered for a realistic modeling of the organic quantum spin liquid systems
like the Pd(dmit)2 salt.


title: Stochastic duality of Markov processes: a study via generators

abstract:
  The paper is devoted to a systematic study of the duality of processes in the
sense that $E f(X_t^x,y)=E f (x, Y_t^y)$ for a certain $f$.
  This classical topic has well known applications in interacting particles,
intertwining, superprocesses, stochastic monotonicity, exit - entrance laws,
ruin probabilities in finances, etc. Aiming mostly at the case of $f$ depending
on the difference of its arguments, we shall give a systematic study of duality
via the analysis of the generators of dual Markov processes leading to various
results and insights.


title: Three dimensional geometries and the analysis of H II regions

abstract:
  We compare emission line intensities from photoionization models of smooth
and fractal shell geometries for low density H II regions, with particular
focus on the low-ionization diagnostic diagram [N II]/H-alpha vs H-alpha.
Building on previously published models and observations of Barnard's Loop, we
show that the observed range of intensities and variations in the line
intensity ratios may be reproduced with a three dimensional shell geometry. Our
models adopt solar abundances throughout the model nebula, in contrast with
previous one dimensional modeling which suggested the variations in line
intensity ratios could only be reproduced if the heavy element abundances were
increased by a factor of 1.4. For spatially resolved H II regions, the multiple
sightlines that pierce and sample different ionization and temperature
conditions within smooth and fractal shells produce a range of line intensities
that are easily overlooked if only the total integrated intensities from the
entire nebula model are computed. Our conclusion is that inference of H II
region properties, such as elemental abundances, via photoionization models of
one dimensional geometries must be treated with caution and further tested
through three dimensional modeling.


title:
On some non-linear boundary value problems related to a Black--Scholes
  model with transaction costs

abstract:
  We deal with some generalizations on a Black--Scholes model arising in
financial mathematics. As novelty in this paper, we consider a variable
volatility and abstract functional boundary conditions, which allow us to treat
a very large class of problems involving Black--Scholes equation. Our main
results involve the existence of extremal solutions in presence of lower and
upper solutions. Some examples of application are provided too.


title: BAL QSOs and Extreme UFOs: the Eddington connection

abstract:
  We suggest a common physical origin connecting the fast, highly ionized winds
(UFOs) seen in nearby AGN, and the slower and less ionized winds of BAL QSOs.
The primary difference is the mass loss rate in the wind, which is ultimately
determined by the rate at which mass is fed towards the central supermassive
black hole (SMBH) on large scales. This is below the Eddington accretion rate
in most UFOs, and slightly super-Eddington in extreme UFOs such as PG1211+143,
but ranges up to $\sim 10-50$ times this in BAL QSOs. For UFOs this implies
black hole accretion rates and wind mass loss rates which are at most
comparable to Eddington, giving fast, highly-ionized winds. In contrast BAL QSO
black holes have mildly super-Eddington accretion rates, and drive winds whose
mass loss rates are significantly super-Eddington, and so are slower and less
ionized. This picture correctly predicts the velocities and ionization states
of the observed winds, including the recently-discovered one in SDSS
J1106+1939. We suggest that luminous AGN may evolve through a sequence from BAL
QSO through LoBAL to UFO-producing Seyfert or quasar as their Eddington factors
drop during the decay of a bright accretion event. LoBALs correspond to a
short-lived stage in which the AGN radiation pressure largely evacuates the
ionization cone, but before the large-scale accretion rate has dropped to the
Eddington value. We show that sub-Eddington wind rates would produce an $M -
\sigma$ relation lying above that observed. We conclude that significant SMBH
mass growth must occur in super-Eddington phases, either as BAL QSOs, extreme
UFOs, or obscured from direct observation.


title: Short Message Noisy Network Coding with a Decode-Forward Option

abstract:
  Short message noisy network coding (SNNC) differs from long message noisy
network coding (LNNC) in that one transmits many short messages in blocks
rather than using one long message with repetitive encoding. Several properties
of SNNC are developed. First, SNNC with backward decoding achieves the same
rates as SNNC with offset encoding and sliding window decoding for memoryless
networks where each node transmits a multicast message. The rates are the same
as LNNC with joint decoding. Second, SNNC enables early decoding if the channel
quality happens to be good. This leads to mixed strategies that unify the
advantages of decode-forward and noisy network coding. Third, the best decoders
sometimes treat other nodes' signals as noise and an iterative method is given
to find the set of nodes that a given node should treat as noise sources.


title: Interface dynamics in discrete forward-backward diffusion equations

abstract:
  We study the motion of phase interfaces in a diffusive lattice equation with
bistable nonlinearity and derive a free boundary problem with hysteresis to
describe the macroscopic evolution in the parabolic scaling limit.
  The first part of the paper deals with general bistable nonlinearities and is
restricted to numerical experiments and heuristic arguments. We discuss the
formation of macroscopic data and present numerical evidence for pinning,
depinning, and annihilation of interfaces. Afterwards we identify a generalized
Stefan condition along with a hysteretic flow rule that characterize the
dynamics of both standing and moving interfaces.
  In the second part, we rigorously justify the limit dynamics for
single-interface data and a special piecewise affine nonlinearity. We prove
persistence of such data, derive upper bounds for the macroscopic interface
speed, and show that the macroscopic limit can indeed be described by the free
boundary problem. The fundamental ingredient to our proofs is a representation
formula that links the solutions of the nonlinear lattice to the discrete heat
kernel and enables us to derive macroscopic compactness results in the space of
continuous functions.


title:
OGLE-2002-BLG-360: from a gravitational microlensing candidate to an
  overlooked red transient

abstract:
  OGLE-2002-BLG-360 was discovered as a microlensing candidate by the OGLE-III
project. The subsequent light curve however clearly showed that the brightening
of the object could not have resulted from the gravitational microlensing
phenomenon. We aim to explain the nature of OGLE-2002-BLG-360 and its eruption
observed in 2002--2006. The observational data primarily come from the archives
of the OGLE project, which monitored the object in 2001--2009. The archives of
the MACHO and MOA projects also provided us with additional data obtained in
1995--99 and 2000--2005, respectively. These data allowed us to analyse the
light curve of the object during its eruption, as well as the potential
variability of its progenitor. In the archives of several infrared surveys,
namely 2MASS, MSX, Spitzer, AKARI, WISE, and VVV, we found measurements of the
object, which allowed us to study the spectral energy distribution (SED) of the
object. We constructed a simple model of a star surrounded by a dusty envelope,
which was used to interpret the observed SED. Our analysis of the data clearly
shows that OGLE-2002-BLG-360 was most probably a red transient, i.e. an object
similar in nature to V838 Mon, whose eruption was observed in 2002. The SED in
all phases, i.e. progenitor, eruption, and remnant, was dominated by infrared
emission, which we interpret as evidence of dust formation in an intense mass
outflow. Since 2009 the object has been completely embedded in dust. We suggest
that the progenitor of OGLE-2002-BLG-360 was a binary, which had entered the
common-envelope phase a long time (at least decades) before the observed
eruption, and that the eruption resulted from the final merger of the binary
components. We point out similarities between OGLE-2002-BLG-360 and CK Vul,
whose eruption was observed in 1670--72, and this strengthens the hypothesis
that CK Vul was also a red transient.


title: Deforming Geometric Transitions

abstract:
  After a quick review of the wild structure of the complex moduli space of
Calabi-Yau threefolds and the role of geometric transitions in this context
(the Calabi-Yau web) the concept of "deformation equivalence" for geometric
transitions is introduced to understand the arrows of the Gross-Reid Calabi-Yau
web as deformation-equivalence classes of geometric transitions. Then the focus
will be on some results and suitable examples to understand under which
conditions it is possible to get "simple" geometric transitions, which are
almost the only well-understood geometric transitions both in mathematics and
in physics.


title:
On the Universality of Inner Black Hole Mechanics and Higher Curvature
  Gravity

abstract:
  Black holes are famous for their universal behavior. New thermodynamic
relations have been found recently for the product of gravitational entropies
over all the horizons of a given stationary black hole. This product has been
found to be independent of the mass for all such solutions of Einstein-Maxwell
theory in d=4,5. We study the universality of this mass independence by
introducing a number of possible higher curvature corrections to the
gravitational action. We consider finite temperature black holes with both
asymptotically flat and (A)dS boundary conditions. Although we find examples
for which mass independence of the horizon entropy product continues to hold,
we show that the universality of this property fails in general. We also derive
further thermodynamic properties of inner horizons, such as the first law and
Smarr relation, in the higher curvature theories under consideration, as well
as a set of relations between thermodynamic potentials on the inner and outer
horizons that follow from the horizon entropy product, whether or not it is
mass independent.


title:
Verification of Artifact-Centric Systems: Decidability and Modeling
  Issues

abstract:
  Artifact-centric business processes have recently emerged as an approach in
which processes are centred around the evolution of business entities, called
artifacts, giving equal importance to control-flow and data. The recent
Guard-State-Milestone (GSM) approach provides means for specifying business
artifacts lifecycles in a declarative manner, using constructs that match how
executive-level stakeholders think about their business. However, it turns out
that formal verification of GSM is undecidable even for very simple
propositional temporal properties. We attack this challenging problem by
translating GSM into a well-studied formal framework. We exploit this
translation to isolate an interesting class of state-bounded GSM models for
which verification of sophisticated temporal properties is decidable. We then
introduce some guidelines to turn an arbitrary GSM model into a state-bounded,
verifiable model.


title:
Probe region expression estimation for RNA-seq data for improved
  microarray comparability

abstract:
  Rapidly growing public gene expression databases contain a wealth of data for
building an unprecedentedly detailed picture of human biology and disease. This
data comes from many diverse measurement platforms that make integrating it all
difficult. Although RNA-sequencing (RNA-seq) is attracting the most attention,
at present the rate of new microarray studies submitted to public databases far
exceeds the rate of new RNA-seq studies. There is clearly a need for methods
that make it easier to combine data from different technologies. In this paper,
we propose a new method for processing RNA-seq data that yields gene expression
estimates that are much more similar to corresponding estimates from microarray
data, hence greatly improving cross-platform comparability. The method we call
PREBS is based on estimating the expression from RNA-seq reads overlapping the
microarray probe regions, and processing these estimates with microarray
summarisation algorithm RMA. Using paired microarray and RNA-seq samples from
TCGA LAML data set we show that PREBS expression estimates derived from RNA-seq
are more similar to microarray-based expression estimates than those from other
RNA-seq processing methods. In an experiment to retrieve paired microarray
samples from a database using an RNA-seq query sample, gene signatures defined
based on PREBS expression estimates were found to be much more accurate than
those from other methods. PREBS also allows new ways of using RNA-seq data,
such as expression estimation for microarray probe sets. An implementation of
the proposed method is available in the Bioconductor package `prebs'.


title:
Dark matter in disk galaxies I: a Markov Chain Monte Carlo method and
  application to DDO 154

abstract:
  We present a new method to constrain the dark matter halo density profiles of
disk galaxies. Our algorithm employs a Markov Chain Monte Carlo (MCMC) approach
to explore the parameter space of a general family of dark matter profiles. We
improve upon previous analyses by considering a wider range of halo profiles
and by explicitly identifying cases in which the data are insufficient to break
the degeneracies between the model parameters. We demonstrate the robustness of
our algorithm using artificial data sets and show that reliable estimates of
the halo density profile can be obtained from data of comparable quality to
those currently available for low surface brightness (LSB) galaxies. We present
our results in terms of physical quantities which are constrained by the data,
and find that the logarithmic slope of the halo density profile at the radius
of the innermost data point of a measured rotation curve can be strongly
constrained in LSB ([Vstar/Vobs]max ~ 0.16) galaxies. High surface brightness
galaxies ([Vstar/Vobs]max ~ 0.79) require additional information on the
mass-to-light ratio of the stellar population - our approach naturally
identifies those galaxies for which this is necessary. We apply our method to
observed data for the dwarf irregular galaxy DDO 154 and recover a logarithmic
halo slope of -0.39 +- 0.11 at a radius of 0.14 kpc. Our analysis validates
earlier estimates which were based on the fitting of a limited set of
individual halo models, but constitutes a more robust constraint than was
possible using other techniques since it marginalises over a wide range of halo
profiles.


title: Emergent Heavy Fermion Behavior at the Wigner-Mott Transition

abstract:
  We study charge ordering driven by Coulomb interactions on triangular
lattices relevant to the Wigner-Mott transition in two dimensions. Dynamical
mean-field theory reveals the pinball liquid phase, a charge ordered metallic
phase containing quasi-localized (pins) coexisting with itinerant (balls)
electrons. Based on an effective periodic Anderson model for this phase, we
find an antiferromagnetic Kondo coupling between pins and balls and strong
quasiparticle renormalization. Non-Fermi liquid behavior can occur in such
charge ordered systems due to spin-flip scattering of itinerant electrons off
the pins in analogy with heavy fermion compounds.


title:
Propagation of nuclear data uncertainties for ELECTRA burn-up
  calculations

abstract:
  The European Lead-Cooled Training Reactor (ELECTRA) has been proposed as a
training reactor for fast systems within the Swedish nuclear program. It is a
low-power fast reactor cooled by pure liquid lead. In this work, we propagate
the uncertainties in Pu-239 transport data to uncertainties in the fuel
inventory of ELECTRA during the reactor life using the Total Monte Carlo
approach (TMC). Within the TENDL project the nuclear models input parameters
were randomized within their uncertainties and 740 Pu-239 nuclear data
libraries were generated. These libraries are used as inputs to reactor codes,
in our case SERPENT, to perform uncertainty analysis of nuclear reactor
inventory during burn-up. The uncertainty in the inventory determines
uncertainties in: the long-term radio-toxicity, the decay heat, the evolution
of reactivity parameters, gas pressure and volatile fission product content. In
this work, a methodology called fast TMC is utilized, which reduces the overall
calculation time. The uncertainty in the long-term radiotoxicity, decay heat,
gas pressure and volatile fission products were found to be insignificant.
However, the uncertainty of some minor actinides were observed to be rather
large and therefore their impact on multiple recycling should be investigated
further. It was also found that, criticality benchmarks can be used to reduce
inventory uncertainties due to nuclear data. Further studies are needed to
include fission yield uncertainties, more isotopes, and a larger set of
benchmarks.


title:
Newtonian noise limit in atom interferometers for gravitational wave
  detection

abstract:
  In this work we study the influence of the newtonian noise on atom
interferometers applied to the detection of gravitational waves, and we compute
the resulting limits to the sensitivity in two different configurations: a
single atom interferometer, or a pair of atom interferometers operated in a
differential configuration. We find that for the instrumental configurations
considered, and operating in the frequency range [0.1-10] Hz, the limits would
be comparable to those affecting large scale optical interferometers.


title:
Modified Korteweg-de Vries equation: modulated elliptic wave and a train
  of asymptotic solitons

abstract:
  We study the long-time asymptotic behavior of the Cauchy problem for the
modified Korteweg - de Vries equation with an initial function of the step
type. This function rapidly tends to zero as $x\to+\infty$ and to some positive
constant c as $x\to-\infty$. In 1989 E. Khruslov and V. Kotlyarov have found
that for a large time the solution breaks up into a train of asymptotic
solitons located in the domain $4c^2t-C_N \ln t<x\leq4c^2t$ ($C_N$ is a
constant). The number N of these solitons grows unboundedly as $t\to\infty$. In
2010 V. Kotlyarov and A. Minakov have studied temporary asymptotics of the
solution of the Cauchy problem on the whole line and have found that in the
domain $-6c^2 t<x<4c^2t$ this solution is described by a modulated elliptic
wave. We considere here the modulated elliptic wave in the domain $4c^2t-C_N
\ln t<x<4c^2t$. Our main result shows that the modulated elliptic wave also
breaks up into solitons, which are similar to the asymptotic solitons, but
differ from them in phase. It means that the modulated elliptic wave does not
represent the asymptotics of the solution in the domain $4c^2t-C_N \ln
t<x<4c^2t$. The correct asymptotic behavior of the solution is given by the
train of asymptotic solitons. However, in the asymptotic regime as $t\to\infty$
in the region $4c^2t-\frac{N+1/4}{c}\ln t<x<4c^2t-\frac{N-3/4}{c}\ln t$ we can
watch precisely a pair of solitons with numbers N. One of them is the
asymptotic soliton while the other soliton is generated from the elliptic wave.
Their phases become closer to each other for a large N, i.e. these solitons are
also close to each other. This result gives the answer on a very important
question about matching of the asymptotic formulas in the mentioned region
where the both formulas are well-defined. We have a new and earlier unknown
mechanism of matching of the asymptotics of the solution in the adjacent
regions.


title:
Analytic Discs, Global Extremal Functions and Projective Hulls in
  Projective Space

abstract:
  Using a recent result of L\'arusson and Poletsky regarding plurisubharmonic
subextensions we prove a disc formula for the quasiplurisubharmonic global
extremal function for domains in complex projective space. As a corollary we
get a characterization of the projective hull for connected compact sets in
complex projective space by the existence of analytic discs.


title:
Network Coding for Energy-Efficient Distributed Storage System in
  Wireless Sensor Networks

abstract:
  A network coding-based scheme is proposed to improve the energy efficiency of
distributed storage systems in WSNs (wireless sensor networks), which mainly
focuses on two problems: firstly, consideration is given to effective
distributed storage technology in WSNs; secondly, we address how to repair the
data in failed storage nodes with less resource. For the first problem, we
propose a method to obtain a sparse generator matrix to construct network
codes, and this sparse generator matrix is proven to be the sparsest.
Benefiting from the sparse generator matrix, the energy consumption required to
implement distributed storage is reduced. For the second problem, we designed a
network coding-based iterative repair method, which adequately utilizes the
idea of re-encoding at intermediate nodes from network coding theory.
Benefiting from the re-encoding, the energy consumption required by data repair
is significantly reduced. Moreover, we provide an explicit lower bound of field
size required by this scheme, which implies that this scheme can work over a
very small field and the required computation overhead of coding is very low.
The simulation result verifies that by using our scheme, the total energy
consumption required to implement distributed storage system in WSNs can be
reduced on the one hand, and on the other hand, this method can also balance
energy consumption of the networks.


title:
Properties of the radio jet emission of four gamma-ray Narrow Line
  Seyfert 1 galaxies

abstract:
  The detection of gamma rays from a small number of Narrow Line Seyfert 1
galaxies by the LAT instrument onboard Fermi seriously challenged our
understanding of AGN physics. Among the most important findings associated with
their discovery has been the realisation that smaller-mass black holes seem to
be hosted by these systems. Immediately after their discovery a radio multi-
frequency monitoring campaign was initiated to understand their jet radio
emission. Here the first results of the campaign are presented. The light
curves and some first variability analyses are discussed, showing that the
brightness temperatures and Doppler factors are moderate. The phenomenologies
are typically blazar-like. The frequency domain on the other hand indicates
intense spectral evolution and the variability patterns indicate mechanisms
similar to those acting in the jets of BL Lacs and FSRQs. Finally, the linear
polarisation also reveals the presence of a quiescent, optically thin jet in
certain cases.


title:
Magnetic properties of double exchange biased diluted magnetic
  alloy/ferromagnet/antiferromagnet trilayers

abstract:
  The magnetic properties of trilayers consisting of a diluted magnetic alloy,
CuMn (Cu0.99Mn0.01), a soft ferromagnet, Py(Ni0.8Fe0.2), and an
antiferromagnet, alpha-Fe2O3, were investigated. The samples, grown by UHV
magnetron sputtering, were magnetically characterized in the temperature range
T = 3-100 K. Typical exchange bias features, namely clear hysteresis cycle
shifts and coercivity enhancements, were observed. Moreover the presence of an
inverse bias, which had been already reported for spin glass-based structures,
was also obtained in a well defined range of temperatures and CuMn thicknesses.


title: Distribution of Artin-Schreier-Witt extensions

abstract:
  The article at hand contains exact asymptotic formulas for the distribution
of conductors of abelian p-extensions of global function fields of
characteristic p. These yield a new conjecture for the distribution of
discriminants fueled by an interesting lower bound.


title:
Resonance Interaction Induced by Metal Surfaces Catalyses Atom Pair
  Breakage

abstract:
  We present the theory for retarded resonance interaction between two
identical atoms at arbitrary positions near a metal surface. The dipole-dipole
resonance interaction force that binds isotropically excited atom pairs
together in free space may turn repulsive close to an ideal (totally
reflecting) metal surface. On the other hand, close to an infinitely permeable
surface it may turn more attractive. We illustrate numerically how the
dipole-dipole resonance interaction between two oxygen atoms near a metal
surface may provide a repulsive energy of the same order of magnitude as the
ground-state binding energy of an oxygen molecule. As a complement we also
present results from density-functional theory.


title: Design and Operation of FACT -- The First G-APD Cherenkov Telescope

abstract:
  The First G-APD Cherenkov Telescope (FACT) is designed to detect cosmic
gamma-rays with energies from several hundred GeV up to about 10 TeV using the
Imaging Atmospheric Cherenkov Technique. In contrast to former or existing
telescopes, the camera of the FACT telescope is comprised of solid-state
Geiger-mode Avalanche Photodiodes (G-APD) instead of photomultiplier tubes for
photo detection. It is the first full-scale device of its kind employing this
new technology. The telescope is operated at the Observatorio del Roque de los
Muchachos (La Palma, Canary Islands, Spain) since fall 2011. This paper
describes in detail the design, construction and operation of the system,
including hardware and software aspects. Technical experiences gained after one
year of operation are discussed and conclusions with regard to future projects
are drawn.


title: Velocity renormalization in graphene from lattice Monte Carlo

abstract:
  We compute the Fermi velocity of the Dirac quasiparticles in clean graphene
at the charge neutrality point for strong Coulomb coupling alpha_g. We perform
a Lattice Monte Carlo calculation within the low-energy Dirac theory, which
includes an instantaneous, long-range Coulomb interaction. We find a
renormalized Fermi velocity v_FR > v_F, where v_F = c/300. Our results are
consistent with a momentum-independent v_FR which increases approximately
linearly with alpha_g, although a logarithmic running with momentum cannot be
excluded at present. At the predicted critical coupling alpha_gc for the
semimetal-insulator transition due to excitonic pair formation, we find
v_FR/v_F = 3.3, which we discuss in light of experimental findings for v_FR/v_F
at the charge neutrality point in ultra-clean suspended graphene.


title: Competition and Success in the Meme Pool: a Case Study on Quickmeme.com

abstract:
  The advent of social media has provided data and insights about how people
relate to information and culture. While information is composed by bits and
its fundamental building bricks are relatively well understood, the same cannot
be said for culture. The fundamental cultural unit has been defined as a
"meme". Memes are defined in literature as specific fundamental cultural
traits, that are floating in their environment together. Just like genes
carried by bodies, memes are carried by cultural manifestations like songs,
buildings or pictures. Memes are studied in their competition for being
successfully passed from one generation of minds to another, in different ways.
In this paper we choose an empirical approach to the study of memes. We
downloaded data about memes from a well-known website hosting hundreds of
different memes and thousands of their implementations. From this data, we
empirically describe the behavior of these memes. We statistically describe
meme occurrences in our dataset and we delineate their fundamental traits,
along with those traits that make them more or less apt to be successful.


title: Free Convolution Operators and Free Hall Transform

abstract:
  We define an extension of the polynomial calculus on a W*-probability space
by introducing an abstract algebra which contains polynomials. This extension
allows us to define transition operators for additive and multiplicative free
convolution. It also permits us to characterize the free Segal-Bargmann
transform and the free Hall transform introduced by Biane, in a manner which is
closer to classical definitions. Finally, we use this extension of polynomial
calculus to prove two asymptotic results on random matrices: the convergence
for each fixed time, as N tends to infinity, of the *-distribution of the
Brownian motion on the linear group GL_N(C) to the *-distribution of a free
multiplicative circular Brownian motion, and the convergence of the classical
Hall transform on U(N) to the free Hall transform.


title: Higgs properties in a broken Inert Doublet Model

abstract:
  We consider a model for the Higgs sector with two scalar doublets and a
broken $Z_2$ symmetry, the Stealth Doublet Model, where the $Z_2$ symmetry is
manifest in the Yukawa sector but broken by the scalar potential. This model
can be seen as a generalization of the Inert Doublet Model. One of the doublets
is the Higgs doublet that participates in electroweak symmetry breaking and
couples to fermions. The other doublet does not couple to fermions at tree
level and does not acquire a vacuum expectation value. The broken $Z_2$
symmetry leads to interesting phenomenology such as mixing between the two
doublets and charged and CP-odd scalars that can be light and have unusual
decay channels. We present theoretical and experimental constraints on the
model and consider the recent observation of a Higgs boson at the LHC. The data
on the $H\to\gamma\gamma$ channel can be naturally accommodated in the model,
with either the lightest or the heaviest CP-even scalar playing the role of the
observed particle.


title: Enhanced optomechanical readout using optical coalescence

abstract:
  We present a scheme to strongly enhance the readout sensitivity of the
squared displacement of a mobile scatterer placed in a Fabry-P\'erot cavity. We
investigate the largely unexplored regime of cavity electrodynamics in which a
highly reflective element positioned between the end mirrors of a symmetric
Fabry-P\'erot resonator strongly modifies the cavity response function, such
that two longitudinal modes with different spatial parity are brought close to
frequency degeneracy and interfere in the cavity output field. In the case of a
movable middle reflector we show that the interference in this generic "optical
coalescence" phenomenon gives rise to an enhanced frequency shift of the peaks
of the cavity transmission that can be exploited in optomechanics.


title: Borel measures with a density on a compact semi-algebraic set

abstract:
  Let $K\subset R^n$ be a compact basic semi-algebraic set. We provide a
necessary and sufficient condition (with no a priori bounding parameter) for a
real sequence $y=(y_\alpha)$, $\alpha\in N^n$, to have a finite representing
Borel measure absolutely continuous w.r.t. the Lebesgue measure on $K$, and
with a density in $\cap_{p=1}^\infty L_p(K)$. With an additional condition
involving a bounding parameter, the condition is necessary and sufficient for
existence of a density in $L_\infty(K)$. Moreover, nonexistence of such a
density can be detected by solving finitely many of a hierarchy of semidefinite
programs. In particular, if the semidefinite program at step $d$ of the
hierarchy has no solution then the sequence cannot have a representing measure
on $K$ with a density in $L_p(K)$ for any $p\geq 2d$.


title: Optical constants of refractory oxides at high temperatures

abstract:
  Many cosmic dust species, among them refractory oxides, form at temperatures
higher than 300 K. Nevertheless, most astrophysical studies are based on the
room-temperature optical constants of solids, such as corundum and spinel. A
more realistic approach is needed for these materials, especially in the
context of modeling late-type stars. We aimed at deriving sets of optical
constants of selected, astrophysically relevant oxide dust species with high
melting points. A high-temperature-high-pressure-cell and a Fourier-transform
spectrometer were used to measure reflectance spectra of polished samples. For
corundum (alpha-Al$_2$O$_3$), spinel (MgAl$_2$O$_4$), and alpha-quartz
(SiO$_2$), temperature-dependent optical constants were measured from 300 K up
to more than 900 K. Small particle spectra were also calculated from these
data. All three examined oxides show a significant temperature dependence of
their mid-IR bands. For the case of corundum, we find that the 13$\mu$m
emission feature - seen in the IR spectra of many AGB stars - can very well be
assigned to this mineral species. The best fit of the feature is achieved with
oblate corundum grains at mean temperatures around 550 K. Spinel remains a
viable carrier of the 13$\mu$m feature as well, but only for T < 300 K and
nearly spherical grain shapes. Under such circumstances, spinel grains may also
account for the 31.8$\mu$m band that is frequently seen in sources of the
13$\mu$m feature and which has not yet been identified with certainty.


title: Excluding cycles with a fixed number of chords

abstract:
  Trotignon and Vuskovic completely characterized graphs that do not contain
cycles with exactly one chord. In particular, they show that such a graph G has
chromatic number at most max(3,w(G)). We generalize this result to the class of
graphs that do not contain cycles with exactly two chords and the class of
graphs that do not contain cycles with exactly three chords. More precisely we
prove that graphs with no cycle with exactly two chords have chromatic number
at most 6. And a graph G with no cycle with exactly three chords have chromatic
number at most max(96,w(G)+1).


title: Systematic approach to Delta L=1 processes in thermal leptogenesis

abstract:
  In this work we study the contribution to leptogenesis from Delta L=1 decay
and scattering processes mediated by the Higgs with quarks in the initial and
final states using the formalism of non-equilibrium quantum field theory.
Starting from fundamental equations for correlators of the quantum fields we
derive quantum-corrected Boltzmann and rate equations for the total lepton
asymmetry improved in that they include quantum-statistical effects and medium
corrections to the quasiparticle properties. To compute the collision term we
take into account one- and two-loop contributions to the lepton self-energy and
use the extended quasiparticle approximation for the Higgs two-point function.
The resulting CP-violating and washout reaction densities are numerically
compared to the conventional ones.


title: Logistic regression geometry

abstract:
  This paper looks at effects, due to the boundary, on inference in logistic
regression. It shows that first -- and, indeed, higher -- order asymptotic
results are not uniform across the model. Near the boundary, effects such as
high skewness, discreteness and collinearity dominate, any of which could
render inference based on asymptotic normality suspect. A highly interpretable
diagnostic tool is proposed allowing the analyst to check if the boundary is
going to have an appreciable effect on standard inferential techniques.


title:
Fixed Points for Ciric-G-Contractions in Uniform Spaces Endowed with a
  Graph

abstract:
  In this paper, we generalize the notion of $\lambda$-generalized contractions
introduced by \'Ciri\'c from metric to uniform spaces endowed with a graph and
discuss on the existence and uniqueness of fixed points for this type of
contractions using the basic entourages.


title:
The Rise of Ingot Niobium as a Material for Superconducting
  Radiofrequency Accelerating Cavities

abstract:
  As a result of a collaboration between Jefferson Lab and niobium manufacturer
CBMM, ingot niobium was explored as a possible material for superconducting
radiofrequency (SRF) cavity fabrication. The first single cell cavity from
large grain high purity niobium was fabricated and successfully tested at
Jefferson Lab in 2004. This pioneering work triggered research activities in
other SRF laboratories around the world. Large grain niobium became not only an
interesting alternative material for cavity builders, but also material
scientists and surface scientists were eager to participate in the development
of this material. Most of the original expectations for this material of being
less costly and allowing less expensive fabrication and treatment procedures at
the same performance levels in cavities have been met. Many single cell
cavities made from material of different suppliers have been tested
successfully and several multi-cell cavities have shown the performances
comparable to the best cavities made from standard poly-crystalline niobium.
Several 9-cell cavities fabricated by Research Instruments and tested at DESY
exceeded the best performing fine grain cavities with a record accelerating
gradient of Eacc = 45.6 MV/m. Recently- at JLab- by using a new furnace
treatment procedure a single cell cavity made of ingot niobium performed at a
remarkably high Q0-value (~5x10^10) at an accelerating gradient of ~20 MV/m, at
2K. Such performance levels push the state-of-the art of SRF technology to new
limits and are of great interest for future accelerators. This contribution
reviews the development of ingot niobium technology and attempts to make a case
for this material being the choice for future accelerators.


title:
Numerical results for snaking of patterns over patterns in some 2D
  Selkov-Schnakenberg Reaction-Diffusion systems

abstract:
  For a Selkov--Schnakenberg model as a prototype reaction-diffusion system on
two dimensional domains we use the continuation and bifurcation software
pde2path to numerically calculate branches of patterns embedded in patterns,
for instance hexagons embedded in stripes and vice versa, with a planar
interface between the two patterns. We use the Ginzburg-Landau reduction to
approximate the locations of these branches by Maxwell points for the
associated Ginzburg-Landau system. For our basic model, some but not all of
these branches show a snaking behaviour in parameter space, over the given
computational domains. The (numerical) non-snaking behaviour appears to be
related to too narrow bistable ranges with rather small Ginzburg-Landau energy
differences. This claim is illustrated by a suitable generalized model. Besides
the localized patterns with planar interfaces we also give a number of examples
of fully localized atterns over patterns, for instance hexagon patches embedded
in radial stripes, and fully localized hexagon patches over straight stripes.


title: Sharp isoperimetric inequalities via the ABP method

abstract:
  We prove some old and new isoperimetric inequalities with the best constant
using the ABP method applied to an appropriate linear Neumann problem. More
precisely, we obtain a new family of sharp isoperimetric inequalities with
weights (also called densities) in open convex cones of $\mathbb{R}^n$. Our
result applies to all nonnegative homogeneous weights satisfying a concavity
condition in the cone. Remarkably, Euclidean balls centered at the origin
(intersected with the cone) minimize the weighted isoperimetric quotient, even
if all our weights are nonradial ---except for the constant ones.
  We also study the anisotropic isoperimetric problem in convex cones for the
same class of weights. We prove that the Wulff shape (intersected with the
cone) minimizes the anisotropic weighted perimeter under the weighted volume
constraint.
  As a particular case of our results, we give new proofs of two classical
results: the Wulff inequality and the isoperimetric inequality in convex cones
of Lions and Pacella.


title: Single-File Diffusion in an Interval: First Passage Properties

abstract:
  We investigate the long-time behavior of the survival probability of a tagged
particle in a single-file diffusion in a finite interval. The boundary
conditions are of two types: 1) one boundary is absorbing the second is
reflecting, 2) both boundaries are absorbing. For each type of the boundary
conditions we consider two types of initial conditions: a) initial number of
particles N is given, b) initial concentration of particles is given (N is
random). In all four cases the tagged-particle survival probability exhibits
different asymptotic behavior. When the both boundaries are absorbing we also
consider a case of a random interval length (single-file diffusion on a line
with randomly distributed traps). In the latter setting, the initial
concentration of particles has the same effect on the asymptotic decay of the
survival probability as the concentration of traps.


title: The Hopf algebra of Fliess operators and its dual pre-Lie algebra

abstract:
  We study the Hopf algebra H of Fliess operators coming from Control Theory in
the one-dimensional case. We prove that it admits a graded, finte-dimensional,
connected gradation. Dually, the vector space IR is both a pre-Lie algebra for
the pre-Lie product dual of the coproduct of H, and an associative, commutative
algebra for the shuffle product. These two structures admit a compatibility
which makes IR a Com-pre-Lie algebra. We give a presentation of this object as
a Com-pre-Lie algebra and as a pre-Lie algebra.


title:
Fixed Points of Integral Type Contractions in Uniform Spaces with a
  Graph

abstract:
  In this paper, we discuss the existence of fixed points for integral type
contractions in uniform spaces endowed with both a graph and an $E$-distance.
We also give two sufficient conditions under which the fixed point is unique.
Our main results generalize some recent metric fixed point theorems.


title: Nodal Surfaces in Photoemission from Twisted Bilayer Graphene

abstract:
  Selection rules and interference effects in angle resolved photoemission
spectra from twisted graphene bilayers are studied within a long wavelength
theory for the electronic structure. Using a generic model for the interlayer
coupling, we identify features in the calculated ARPES momentum distributions
that are controlled by the singularities and topological character of its long
wavelength spectrum. We distinguish spectral features that are controlled by
single-layer singularities in the spectrum, their modification by gauge
potentials in each layer generated by the interlayer coupling, and new
energy-dependent interference effects that directly probe the interlayer
coherence. The results demonstrate how the energy- and polarization- dependence
of ARPES spectra can be used to characterize the interlayer coupling in twisted
bilayer graphenes.


title: Very special divisors on 4-gonal real algebraic curves

abstract:
  Given a real curve, we study special linear systems called "very special" for
which the dimension does not satisfy a Clifford type inequality. We classify
all these very special linear systems when the gonality of the curve is small.


title: Security of Plug-and-Play QKD Arrangements with Finite Resources

abstract:
  The security of a passive plug-and-play QKD arrangement in the case of finite
(resources) key lengths is analysed. It is assumed that the eavesdropper has
full access to the channel so an unknown and untrusted source is assumed. To
take into account the security of the BB84 protocol under collective attacks
within the framework of quantum adversaries, a full treatment provides the
well-known equations for the secure key rate. A numerical simulation keeping a
minimum number of initial parameters constant as the total error sought and the
number of pulses is carried out. The remaining parameters are optimized to
produce the maximum secure key rate. Two main strategies are addressed: with
and without two-decoy-states including the optimization of signal to decoy
relationship.


title:
Harmonic analysis and a bentness-like notion in certain finite Abelian
  groups over some finite fields

abstract:
  It is well-known that degree two finite field extensions can be equipped with
a Hermitian-like structure similar to the extension of the complex field over
the reals. In this contribution, using this structure, we develop a modular
character theory and the appropriate Fourier transform for some particular kind
of finite Abelian groups. Moreover we introduce the notion of bent functions
for finite field valued functions rather than usual complex-valued functions,
and we study several of their properties. In particular we prove that this
bentness notion is a consequence of that of Logachev, Salnikov and Yashchenko,
introduced in "Bent functions on a finite Abelian group" (1997). In addition
this new bentness notion is also generalized to a vectorial setting.


title:
xrayutilities: A versatile tool for reciprocal space conversion of
  scattering data recorded with linear and area detectors

abstract:
  We present general algorithms to convert scattering data of linear and area
detectors recorded in various scattering geometries to reciprocal space
coordinates. The presented algorithms work for any goniometer configuration
including popular four-circle, six-circle and kappa goniometers. We avoid the
use of commonly employed approximations and therefore provide algorithms which
work also for large detectors at small sample detector distances. A recipe for
determining the necessary detector parameters including mostly ignored
misalignments is given. The algorithms are implemented in a freely available
open-source package.


title: MCMC Bayesian Estimation in FIEGARCH Models

abstract:
  Bayesian inference for fractionally integrated exponential generalized
autoregressive conditional heteroskedastic (FIEGARCH) models using Markov Chain
Monte Carlo (MCMC) methods is described. A simulation study is presented to
access the performance of the procedure, under the presence of long-memory in
the volatility. Samples from FIEGARCH processes are obtained upon considering
the generalized error distribution (GED) for the innovation process. Different
values for the tail-thickness parameter \nu are considered covering both
scenarios, innovation processes with lighter (\nu<2) and heavier (\nu>2) tails
than the Gaussian distribution (\nu=2). A sensitivity analysis is performed by
considering different prior density functions and by integrating (or not) the
knowledge on the true parameter values to select the hyperparameter values.


title:
Heterostructure bilayer graphene-hBN: Interplay between misalignment,
  interlayer asymmetry, and trigonal warping

abstract:
  We study the superlattice minibands produced by the interplay between moir\'e
pattern induced by hexagonal BN substrate on graphene layer and the interlayer
coupling in bilayer graphene with Bernal stacking (BLG). We compare moir\'e
miniband features in BLG, where they are affected by the interlayer asymmetry
of BLG-hBN heterostructure and trigonal warping characteristic for electrons in
Bernal-stacked bilayers with those found in monolayer graphene.


title: Plasma Diagnostics of the Interstellar Medium with Radio Astronomy

abstract:
  We discuss the degree to which radio propagation measurements diagnose
conditions in the ionized gas of the interstellar medium (ISM). The "signal
generators" of the radio waves of interest are extragalactic radio sources
(quasars and radio galaxies), as well as Galactic sources, primarily pulsars.
The polarized synchrotron radiation of the Galactic non-thermal radiation also
serves to probe the ISM, including space between the emitting regions and the
solar system. Radio propagation measurements provide unique information on
turbulence in the ISM as well as the mean plasma properties such as density and
magnetic field strength. Radio propagation observations can provide input to
the major contemporary questions on the nature of ISM turbulence, such as its
dissipation mechanisms and the processes responsible for generating the
turbulence on large spatial scales. Measurements of the large scale Galactic
magnetic field via Faraday rotation provide unique observational input to
theories of the generation of the Galactic field.


title: Asymmetric transition disks: Vorticity or eccentricity?

abstract:
  Context. Transition disks typically appear in resolved millimeter
observations as giant dust rings surrounding their young host stars. More
accurate observations with ALMA have shown several of these rings to be in fact
asymmetric: they have lopsided shapes. It has been speculated that these rings
act as dust traps, which would make them important laboratories for studying
planet formation. It has been shown that an elongated giant vortex produced in
a disk with a strong viscosity jump strikingly resembles the observed
asymmetric rings.
  Aims. We aim to study a similar behavior for a disk in which a giant planet
is embedded. However, a giant planet can induce two kinds of asymmetries: (1) a
giant vortex, and (2) an eccentric disk. We studied under which conditions each
of these can appear, and how one can observationally distinguish between them.
This is important because only a vortex can trap particles both radially and
azimuthally, while the eccentric ring can only trap particles in radial
direction.
  Methods. We used the FARGO code to conduct the hydro-simulations. We set up a
disk with an embedded giant planet and took a radial grid spanning from 0.1 to
7 times the planet semi-major axis. We ran the simulations with various
viscosity values and planet masses for 1000 planet orbits to allow a fully
developed vortex or disk eccentricity. Afterwards, we compared the dust
distribution in a vortex-holding disk with an eccentric disk using dust
simulations.
  Results. We find that vorticity and eccentricity are distinguishable by
looking at the azimuthal contrast of the dust density. While vortices, as
particle traps, produce very pronounced azimuthal asymmetries, eccentric
features are not able to accumulate millimeter dust particles in azimuthal
direction, and therefore the asymmetries are expected to be modest.


title:
Multimode plasmon excitation and in-situ analysis in top-down fabricated
  plasmonic nanocircuits

abstract:
  We experimentally demonstrate synthesis and in-situ analysis of multimode
plasmonic excitations in two-wire transmission lines supporting a symmetric and
an antisymmetric eigenmode. To this end we irradiate an incoupling antenna with
a diffraction-limited excitation spot exploiting a polarization- and
position-dependent excitation efficiency. Modal analysis is performed by
recording the far-field emission of two mode-specific spatially separated
emission spots at the far end of the transmission line. To illustrate the power
of the approach we selectively determine the group velocities of symmetric and
antisymmetric contributions of a multimode ultrafast plasmon pulse.


title:
Violation of Leggett-type inequalities in the spin-orbit degrees of
  freedom of a single photon

abstract:
  We report the experimental violation of Leggett-type inequalities for a
hybrid entangled state of spin and orbital angular momentum of a single photon.
These inequalities give a physical criterion to verify the possible validity of
a class of hidden-variable theories, originally named "crypto non-local", that
are not excluded by the violation of Bell-type inequalities. In our case, the
tested theories assume the existence of hidden variables associated with
independent degrees of freedom of the same particle, while admitting the
possibility of an influence between the two measurements, i.e. the so-called
contextuality of observables. We observe a violation the Leggett inequalities
for a range of experimental inputs, with a maximum violation of seven standard
deviations, thus ruling out this class of hidden variable models with a high
confidence.


title:
A Link Loss Model for the On-body Propagation Channel for Binaural
  Hearing Aids

abstract:
  Binaural hearing aids communicate with each other through a wireless link for
synchronization. A propagation model is needed to estimate the ear-to-ear link
loss for such binaural hearing aids. The link loss is a critical parameter in a
link budget to decide the sensitivity of the transceiver. In this paper, we
have presented a model for the deterministic component of the ear-to-ear link
loss. The model takes into account the dominant paths having most of the power
of the creeping wave from the transceiver in one ear to the transceiver in
other ear and the effect of the protruding part of the outer ear called pinna.
Simulations are done to validate the model using in-the-ear (ITE) placement of
antennas at 2.45 GHz on two heterogeneous phantoms of different age-group and
body size. The model agrees with the simulations. The ear-to-ear link loss
between the antennas for the binaural hearing aids in the homogeneous SAM
phantom is compared with a heterogeneous phantom. It is found that the absence
of the pinna and the lossless shell in the SAM phantom underestimate the link
loss. This is verified by the measurements on a phantom where we have included
the pinnas fabricated by 3D-printing.


title: Contact processes in crowded environments

abstract:
  Periodically sheared colloids at low densities demonstrate a dynamical phase
transition from an inactive to active phase as the strain amplitude is
increased. The inactive phase consists of no collisions/contacts between
particles in the steady state limit, while in the active phase collisions
persist. To investigate this system at higher densities, we construct and study
a conserved-particle-number contact process with novel three-body interactions,
which are potentially more likely than two-body interactions at higher
densities. For example, consider one active (diffusing) particle colliding with
two inactive (non-diffusing) particles such that they become active, in
addition to spontaneous inactivation. In mean-field, this system exhibits a
continuous dynamical phase transition belonging to the conserved directed
percolation universality class. Simulations on square lattices support the mean
field result. In contrast, the three-body interaction requiring two active
particles to activate one inactive particle exhibits a discontinuous
transition. Finally, inspired by kinetically-constrained models of the glass
transition, we investigate the "caging effect" at even higher particle
densities to look for a second dynamical phase transition back to an inactive
phase. Square lattice simulations suggest a continuous transition with a new
set of exponents differing from conserved directed percolation, i.e. a new
universality class for contact processes with conserved particle number.


title:
Quantification of linear entropy for quantum entanglement in He, H- and
  Ps- ions using highly-correlated Hylleraas functions

abstract:
  The quantum entanglement for the two electrons in three-body atomic systems
such as the helium atom, the hydrogen negative ion and the positronium negative
ion are investigated by employing highly correlated Hylleraas functions to
represent the ground states of such systems. As a measure of the spatial
entanglement, the linear entropy of the reduced density matrix is calculated
for the ground states. The required four-electron (12-dimensional) integrals
are solved analytically such that they are suitable for machine computations.
Results are compared with other calculations when available.


title:
Matter-wave dark solitons and their excitation spectra in spin-orbit
  coupled Bose-Einstein condensates

abstract:
  We present three types of dark solitons in quasi-one-dimensional spin-orbit
coupled repulsive Bose-Einstein condensates. Among these families, two are
always stable, while the third one is only stable sufficiently close to the
linear regime. The solitons' excitation spectra reveal the potential existence
of a second anomalous mode. While the first such mode describes the soliton
oscillatory motion in a parabolic trap, the second, when present, reflects the
double well structure of the underlying single-particle spectrum. This novel
mode results in moving density stripes in the vicinity of the soliton core, or
in an out-of-phase oscillation of the constituent components, with little
effect on the nearly stationary striped total density of the composite soliton.


title:
Pressure dependence of superconducting critical temperature and upper
  critical field of 2H-NbS2

abstract:
  We present measurements of the superconducting critical temperature Tc and
upper critical field Hc2 as a function of pressure in the transition metal
dichalcogenide 2H-NbS2 up to 20 GPa. We observe that Tc increases smoothly from
6K at ambient pressure to about 8.9K at 20GPa. This range of increase is
comparable to the one found previously in 2H-NbSe2. The temperature dependence
of the upper critical field Hc2(T) of 2H-NbS2 varies considerably when
increasing the pressure. At low pressures, Hc2(0) decreases, and at higher
pressures both Tc and Hc2(0) increase simultaneously. This points out that
there are pressure induced changes of the Fermi surface, which we analyze in
terms of a simplified two band approach.


title: Fundamental Photoemission Brightness Limit from Disorder Induced Heating

abstract:
  We determine the limit of the lowest achievable photoemitted electron
temperature, and therefore the maximum achievable electron brightness, due to
heating just after emission into vacuum, applicable to dense relativistic or
nonrelativistic photoelectron beams. This heating is due to poorly screened
Coulomb interactions equivalent to disorder induced heating seen in ultracold
neutral plasmas. We first show that traditional analytic methods of Coulomb
collisions fail for the calculation of this strongly coupled heating. Instead,
we employ an N-body tree algorithm to compute the universal scaling of the
disorder induced heating in fully contained bunches, and show it to agree well
with a simple model utilizing the tabulated correlated energy of one component
plasmas. We also present simulations for beams undergoing Coulomb explosion at
the photocathode, and demonstrate that both the temperature growth and
subsequent cooling must be characterized by correlated effects, as well as
correlation-frozen dynamics. In either case, the induced temperature is found
to be of several meV for typical photoinjector beam densities, a significant
fraction of the intrinsic beam temperature of the coldest semiconductor
photocathodes. Thus, we expect disorder induced heating to become a major
limiting factor in the next generation of photoemission sources delivering
dense bunches and employing ultra-cold photoemitters.


title:
Nonequilibrium dynamics in an optical transition from a neutral quantum
  dot to a correlated many-body state

abstract:
  We investigate the effect of many-body interactions on the optical absorption
spectrum of a charge-tunable quantum dot coupled to a degenerate electron gas.
A constructive Fano interference between an indirect path, associated with an
intra dot exciton generation followed by tunneling, and a direct path,
associated with the ionization of a valence-band quantum dot electron, ensures
the visibility of the ensuing Fermi-edge singularity despite weak absorption
strength. We find good agreement between experiment and renormalization group
theory, but only when we generalize the Anderson impurity model to include a
static hole and a dynamic dot-electron scattering potential. The latter
highlights the fact that an optically active dot acts as a tunable quantum
impurity, enabling the investigation of a new dynamic regime of Fermi-edge
physics.


title:
How Natural Selection Can Create Both Self- and Other-Regarding
  Preferences, and Networked Minds

abstract:
  Biological competition is widely believed to result in the evolution of
selfish preferences. The related concept of the `homo economicus' is at the
core of mainstream economics. However, there is also experimental and empirical
evidence for other-regarding preferences. Here we present a theory that
explains both, self-regarding and other-regarding preferences. Assuming
conditions promoting non-cooperative behaviour, we demonstrate that
intergenerational migration determines whether evolutionary competition results
in a `homo economicus' (showing self-regarding preferences) or a `homo
socialis' (having other-regarding preferences). Our model assumes spatially
interacting agents playing prisoner's dilemmas, who inherit a trait determining
`friendliness', but mutations tend to undermine it. Reproduction is ruled by
fitness-based selection without a cultural modification of reproduction rates.
Our model calls for a complementary economic theory for `networked minds' (the
`homo socialis') and lays the foundations for an evolutionarily grounded theory
of other-regarding agents, explaining individually different utility functions
as well as conditional cooperation.


title: Condensation of circular DNA

abstract:
  A simple model of a circularly closed dsDNA in a poor solvent is considered
as an example of a semi-flexible polymer with self-attraction. To find the
ground states, the conformational energy is computed as a sum of the bending
and torsional elastic components and the effective self-attraction energy. The
model includes a relative orientation or sequence dependence of the effective
attraction forces between different pieces of the polymer chain. Two series of
conformations are analysed: a multicovered circle (a toroid) and a multifold
two-headed racquet. The results are presented as a diagram of state. It is
suggested that the stability of particular conformations may be controlled by
proper adjustment of the primary structure. Application of the model to other
semi-flexible polymers is considered.


title: Orbital stability of Dirac solitons

abstract:
  We prove $H^1$ orbital stability of Dirac solitons in the integrable massive
Thirring model by working with an additional conserved quantity which
complements Hamiltonian, momentum and charge functionals of the general
nonlinear Dirac equations. We also derive a global bound on the $H^1$ norm of
the $L^2$-small solutions of the massive Thirring model.


title:
Sensitivity of the decay of entanglement of quantum dot spin qubits to
  the magnetic field

abstract:
  We study the decay of entanglement of quantum dot electron-spin qubits under
hyperfine interaction mediated decoherence. We show that two qubit entanglement
of a single entangled initial state may exhibit decay characteristic of the two
disentanglement regimes in a single sample, when the external magnetic field is
changed. The transition is manifested by the supression of time-dependent
entanglement oscillations which are superimposed on the slowly varying
entanglement decay related to phase decoherence (which result in oscillatory
behaviour of entanglement sudden death time as a function of the magnetic
field). This unique behaviour allows us to propose the double quantum dot
two-electron spin Bell state as a promising candidate for precise measurements
of the magnetic field.


title: Sarason Conjecture on the Bergman space

abstract:
  We provide a counterexample to the Sarason Conjecture for the Bergman space
and present a characterisation of bounded Toeplitz products on the Bergman
space in terms of test functions by means of a dyadic model approach. We also
present some results about two-weighted estimates for the Bergman projection.
Finally, we introduce the class $B_{\infty}$ and give sharp estimates for the
one-weighted Bergman projection.


title:
Strain mediated suppression of the metal-insulator transition in EuNiO3
  thin films

abstract:
  Ultrathin epitaxial films of EuNiO3 were grown on a series of substrates
traversing highly compressive (- 2.4%) to highly tensile (2.5%) lattice
mismatch. X-ray diffraction measurements showed the expected c-lattice
parameter shift for compressive strain, but no detectable shift for tensilely
strained substrates, while reciprocal space mapping confirmed the tensile
strained film maintained epitaxial coherence. Transport measurements showed a
successively (from tensile to compressive) lower resistance and a complete
suppression of the metalinsulator transition at highly compressive lattice
mismatch. Corroborating these findings, X-ray absorption spectroscopy
measurements revealed a strong multiplet splitting in the tensile samples that
progressively weakens with increasing compressive strain that, combined with
cluster calculations, showed enhanced covalence between Ni-d and O-p orbitals
leads to the metallic state.


title: Control of atomic Rydberg states using guided electrons

abstract:
  We present and analyze a simple model to illustrate the possibility of
Rydberg state control by means of a moving guided electron. Specifically, we
consider alkali metal atoms whose valence electron is initially prepared in a
Rydberg s-state and investigate state changes induced by the interaction with
the nearby passing electron. We analyze the dependence of the atomic final
state, obtained after the passage, on the electron's momentum. We identify
experimentally accessible parameter regimes and discuss the experimental
feasibility of the proposed scheme. We furthermore discuss the possibility to
excite and manipulate many-body states of a chain of interacting Rydberg atoms.


title: Stable representation homology and Koszul duality

abstract:
  This paper is a sequel to [BKR], where we studied the derived affine scheme
DRep_n(A) of the classical representation scheme Rep_n(A) for an associative
k-algebra A. In [BKR], we have constructed canonical trace maps Tr_n(A): HC(A)
-> H[DRep_n(A)]^GL extending the usual characters of representations to higher
cyclic homology. This raises a question whether a well known theorem of Procesi
[P] holds in the derived setting: namely, is the algebra homomorphism
Sym[Tr_n(A)]: Sym[HC(A)] -> H[DRep_n(A)]^GL defined by Tr_n(A) surjective ? In
the present paper, we answer this question for augmented algebras. Given such
an algebra, we construct a canonical dense DG subalgebra DRep_\infty(A)^Tr of
the topological DG algebra DRep_\infty(A)^{GL_\infty}. It turns out that on
passing to the inverse limit (as n -> \infty), the family of maps Sym[Tr_n(A)]
"stabilizes" to an isomorphism Sym[\bar{HC}(A)] = H[DRep_\infty(A)^Tr]. The
derived version of Procesi's theorem does therefore hold in the limit. However,
for a fixed (finite) n, there exist homological obstructions to the
surjectivity of Sym[Tr_n(A)], and we show on simple examples that these
obstructions do not vanish in general. We compare our result with the classical
theorem of Loday-Quillen and Tsygan on stable homology of matrix Lie algebras.
We show that the relative Chevalley-Eilenberg complex C(gl_\infty(A),
gl_\infty(k); k) equipped with the natural coalgebra structure is Koszul dual
to the DG algebra DRep_\infty(A)^Tr. We also extend our main results to
bigraded DG algebras, in which case we show that DRep_{\infty}(A)^Tr =
DRep_{\infty}(A)^GL_{\infty}. As an application, we compute the (bigraded)
Euler characteristics of DRep_\infty(A)^GL_{\infty} and \bar{HC}(A) and derive
some interesting combinatorial identities.


title:
Laser-Induced Magnetic Nanostructures with Tunable Topological
  Properties

abstract:
  We report the creation and real-space observation of magnetic structures with
well-defined topological properties and a lateral size as low as about 150 nm.
They are generated in a thin ferrimagnetic film by ultrashort single optical
laser pulses. Thanks to their topological properties, such structures can be
classified as Skyrmions of a particular type that does not require an
externally applied magnetic field for stabilization. Besides Skyrmions, we are
able to generate magnetic features with topological characteristics that can be
tuned by changing the laser fluence. The stability of such features is
accounted for by an analytical model based on the interplay between the
exchange and the magnetic dipole-dipole interactions


title: Block Triangular Preconditioning for Stochastic Galerkin Method

abstract:
  In this paper we study fast iterative solvers for the large sparse linear
systems resulting from the stochastic Galerkin discretization of stochastic
partial differential equations. A block triangular preconditioner is introduced
and applied to the Krylov subspace methods, including the generalized minimum
residual method and the generalized preconditioned conjugate gradient method.
This preconditioner utilizes the special structures of the stochastic Galerkin
matrices to achieve high efficiency. Spectral bounds for the preconditioned
matrix are provided for convergence analysis. The preconditioner system can be
solved approximately by geometric multigrid V-cycle. Numerical results indicate
that the block triangular preconditioner has better performance than the
traditional block diagonal preconditioner for stochastic problems with large
variance.


title: Trouble With The Curve: Improving MLB Pitch Classification

abstract:
  The PITCHf/x database has allowed the statistical analysis of of Major League
Baseball (MLB) to flourish since its introduction in late 2006. Using PITCHf/x,
pitches have been classified by hand, requiring considerable effort, or using
neural network clustering and classification, which is often difficult to
interpret. To address these issues, we use model-based clustering with a
multivariate Gaussian mixture model and an appropriate adjustment factor as an
alternative to current methods. Furthermore, we describe a new pitch
classification algorithm based on our clustering approach to address the
problems of pitch misclassification. We illustrate our methods for various
pitchers from the PITCHf/x database that covers a wide variety of pitch types.


title: Asynchronous Gossip-Based Random Projection Algorithms Over Networks

abstract:
  We consider a fully distributed constrained convex optimization problem over
a multi-agent (no central coordinator) network. We propose an asynchronous
gossip-based random projection (GRP) algorithm that solves the distributed
problem using only local communications and computations. We analyze the
convergence properties of the algorithm for an uncoordinated diminishing
stepsize and a constant stepsize. For a diminishing stepsize, we prove that the
iterates of all agents converge to the same optimal point with probability 1.
For a constant stepsize, we establish an error bound on the expected distance
from the iterates of the algorithm to the optimal point. We also provide
simulation results on a distributed robust model predictive control problem.


title:
Complementarity of dark matter direct detection: the role of bolometric
  targets

abstract:
  We study how the combined observation of dark matter in various direct
detection experiments can be used to determine the phenomenological properties
of WIMP dark matter: mass, spin-dependent (SD) and spin-independent (SI)
scattering cross section off nucleons. A convenient choice of target materials,
including nuclei that couple to dark matter particles through a significantly
different ratio of SD vs SI interactions, could break the degeneracies in the
determination of those parameters that a single experiment cannot discriminate.
In this work we investigate different targets that can be used as scintillating
bolometers and could provide complementary information to germanium and xenon
detectors. We observe that Al2O3 and LiF bolometers could allow a good
reconstruction of the DM properties over regions of the parameter space with a
SD scattering cross section as small as 10^(-5) pb and a SI cross section as
small as 5x10^(-10) pb for a 50 GeV WIMP. In the case of a CaWO4 bolometer the
area in which full complementarity is obtained is smaller but we show that it
can be used to determine the WIMP mass and its SI cross section. For each
target we study the required exposure and background.


title:
Prospects for precision measurements in nuclear beta decay at the LHC
  era

abstract:
  Precision measurements in nuclear beta decay offer a sensitive window to
search for new physics beyond the standard electroweak model and allow also the
determination of the fundamental weak vector coupling in processes involving
the lightest quarks. Searches for new physics are also a strong motivation for
experiments carried out at the high energy frontier reached at the most
powerful particle colliders. It is instructive to confront results from the low
energy and the high energy frontiers in order to look for possible
complementarities and orient new avenues for experiments at low energies. We
review here the status of constraints on new physics obtained from nuclear and
neutron decays and compare them to those from other semi-leptonic processes and
from the LHC. We stress the requirements of new precision experiments in beta
decay in order to impact the search for new physics at the light of current and
projected LHC results. We describe recent experimental results and ongoing
developments in nuclear and neutron beta decay, with emphasis on their planned
goals to improve present limits on exotic weak couplings.


title:
Note: interpreting iterative methods convergence with diffusion point of
  view

abstract:
  In this paper, we explain the convergence speed of different iteration
schemes with the fluid diffusion view when solving a linear fixed point
problem. This interpretation allows one to better understand why power
iteration or Jacobi iteration may converge faster or slower than Gauss-Seidel
iteration.


title: On Bayesian supremum norm contraction rates

abstract:
  Building on ideas from Castillo and Nickl [Ann. Statist. 41 (2013)
1999-2028], a method is provided to study nonparametric Bayesian posterior
convergence rates when "strong" measures of distances, such as the sup-norm,
are considered. In particular, we show that likelihood methods can achieve
optimal minimax sup-norm rates in density estimation on the unit interval. The
introduced methodology is used to prove that commonly used families of prior
distributions on densities, namely log-density priors and dyadic random density
histograms, can indeed achieve optimal sup-norm rates of convergence. New
results are also derived in the Gaussian white noise model as a further
illustration of the presented techniques.


title: Fractal properties of Bessel functions

abstract:
  A fractal oscillatority of solutions of second-order differential equations
near infinity is measured by oscillatory and phase dimensions. The phase
dimension is defined as a box dimension of the trajectory $(x,\dot{x})$ in
$\mathbb{R}^2$ of a solution $x=x(t)$, assuming that $(x,\dot{x})$ is a spiral
converging to the origin. In this work, we study the phase dimension of the
class of second-order nonautonomous differential equations with oscillatory
solutions including the Bessel equation. We prove that the phase dimension of
Bessel functions is equal to 4/3, and that the corresponding trajectory is a
wavy spiral, exhibiting an interesting behavior. The phase dimension of a
generalization of the Bessel equation has been also computed.


title: Gravitation at Very Short Distances

abstract:
  In this note, it is discussed why attempts to renormalize conventional
quantum gravity may be based on a false presumption, because, according to
Verlinde's entropic view of gravity, the gravitational force between two
elementary particles vanishes.


title: Novel distance indicator for gamma-ray bursts associated with supernovae

abstract:
  Context. It has been proposed that the temporal coincidence of a gamma-ray
burst (GRB) and a type Ib/c supernova (SN) can be explained with the concept of
induced gravitational collapse (IGC), induced by the matter ejected from an SN
Ib/c accreting onto a neutron star (NS). The NS is expected to reach the
critical mass necessary for it to collapse to a black hole (BH) and emit a GRB.
We found a standard luminosity light curve behavior in the late-time X-ray
emission of this subclass of GRBs. Aims. We test if this standard behavior in
the luminosity found in this subclass of GRBs can become a redshift estimator
of these sources. Methods. We selected a sample of GRBs that belong to this
subclass of IGC GRBs associated to an SN (IGC GRB-SN sources). These sources
have an isotropic energy $E_{iso} > 10^{52}$ erg and their cosmological
redshifts are in the range of $z = 0.49-1.261$. We focused on the corresponding
X-ray luminosity light curves. Results. We find that all GRBs of the sample
with measured redshift present a standard luminosity late-time light curve in
the $0.3-10$ keV rest-frame energy range. We used these results to estimate the
GRB redshift of the sample without a measured redshift and found results
consistent with other possible redshift indicators. Conclusions. The standard
late-time X-ray luminosity light curve of all GRBs of the sample shows a common
physical mechanism in this particular phase of the X-ray emission, possibly
related to the creation of the NS from the SN process. This scaling law
moreover represents strong evidence of very low or even absent beaming in this
late phase of the X-ray afterglow emission process. This could be a fundamental
tool for estimating the redshift of GRBs that belong to this subclass of
events. We are currently expanding this subclass of GRBs to further verify the
universal validity of this new redshift estimation method.


title: Strongly residual coordinates over A[x]

abstract:
  For a domain A of characteristic zero, a polynomial f over A[x] is called a
strongly residual coordinate if f becomes a coordinate (over A) upon going
modulo x, and f becomes a coordinate upon inverting x. We study the question of
when a strongly residual coordinate is a coordinate, a question closely related
to the Dolgachev-Weisfeiler conjecture. It is known that all strongly residual
coordinates are coordinates for n=2 . We show that a large class of strongly
residual coordinates that are generated by elementaries upon inverting x are in
fact coordinates for arbitrary n, with a stronger result in the n=3 case. As an
application, we show that all Venereau-type polynomials are 1-stable
coordinates.


title: On the supernova remnants with flat radio spectra

abstract:
  A considerable fraction of Galactic supernova remnants (SNRs) characterize
flat spectral indices ($\alpha<0.5$). There are several explanations of the
flat radio spectra of SNRs in the present literature. The most of models
involve a significant contribution of the second-order Fermi mechanism but some
of them also discuss high compressions (>4), contribution of secondary
electrons left over from the decay of charged pions, as well as the possibility
of thermal contamination. In the case of expansion in high density environment,
intrinsic thermal bremsstrahlung could theoretically shape the radio spectrum
of an SNR and also account for observable curved -- "concave up" radio spectra
of some Galactic SNRs. This model could also shed a light on the question of
flat spectral indices determined in some Galactic SNRs. On the other hand,
present knowledge of the radio continuum spectra (integrated flux densities at
different frequencies) of SNRs prevent definite conclusions about the
significance of proposed models so the question on flat spectral indices still
remains open. New observations, especially at high radio continuum frequencies,
are expected to solve these questions in the near future. Finally, as there is
a significant connection between the majority of Galactic SNRs with flat
integrated radio spectrum and their detection in $\gamma$-rays as well as
detection of radiative recombination continua in their X-ray spectra, the
analysis of high energy properties of these SNRs is very important.


title: On time and space double-slit experiments

abstract:
  Time double-slit interference experiments have been achieved and presented as
complementary to spatial double-slit interference experiments, providing a
further confirmation of the wave-particle duality. Numerical solutions of the
free particle time dependent Schr\"odinger equation were presented as
explanation of the experimental results, but have been objected to on the basis
that the standard non relativistic quantum theory does not have the property of
coherence in time. In this note the theoretical and experimental results are
derived in a schematic but analytic solution of the TDSE with appropiate
initial boundary conditions. The particular boundary conditions are justified
by the experimental setups that actually result in having only a single
electron at any given time in the double-slit arrangement; and consequently
achieve the construction of double peak single electron wave packets. The
progressive complementarity of "which-path" ("which-time") information and
"space interference" ("oscillating time transient") pattern build up is also
exhibited.


title: Tidal turbine array optimisation using the adjoint approach

abstract:
  Oceanic tides have the potential to yield a vast amount of renewable energy.
Tidal stream generators are one of the key technologies for extracting and
harnessing this potential. In order to extract an economically useful amount of
power, hundreds of tidal turbines must typically be deployed in an array. This
naturally leads to the question of how these turbines should be configured to
extract the maximum possible power: the positioning and the individual tuning
of the turbines could significantly influence the extracted power, and hence is
of major economic interest. However, manual optimisation is difficult due to
legal site constraints, nonlinear interactions of the turbine wakes, and the
cubic dependence of the power on the flow speed. The novel contribution of this
paper is the formulation of this problem as an optimisation problem constrained
by a physical model, which is then solved using an efficient gradient-based
optimisation algorithm. In each optimisation iteration, a two-dimensional
finite element shallow water model predicts the flow and the performance of the
current array configuration. The gradient of the power extracted with respect
to the turbine positions and their tuning parameters is then computed in a
fraction of the time taken for a flow solution by solving the associated
adjoint equations. These equations propagate causality backwards through the
computation, from the power extracted back to the turbine positions and the
tuning parameters. This yields the gradient at a cost almost independent of the
number of turbines, which is crucial for any practical application. The utility
of the approach is demonstrated by optimising turbine arrays in four idealised
scenarios and a more realistic case with up to 256 turbines in the Inner Sound
of the Pentland Firth, Scotland.


title: Nonlocal Gravity: Damping of Linearized Gravitational Waves

abstract:
  In nonlocal general relativity, linearized gravitational waves are damped as
they propagate from the source to the receiver in the Minkowski vacuum.
Nonlocal gravity is a generalization of Einstein's theory of gravitation in
which nonlocality is due to the gravitational memory of past events. That
nonlocal gravity is dissipative is demonstrated in this paper within certain
approximation schemes. The gravitational memory drag leads to the decay of the
amplitude of gravitational waves given by the exponential damping factor exp
(-t/\tau), where $\tau$ depends on the kernel of nonlocal gravity. The damping
time $\tau$ is estimated for gravitational waves of current observational
interest and is found to be of the order of, or longer than, the age of the
universe.


title:
The classification of compact simply connected biquotients in dimension
  4 and 5

abstract:
  We classify all compact simply connected biquotients of dimension 4 and 5. In
particular, all pairs of groups $(G,H)$ and embeddings $H\rightarrow G\times G$
giving rise to a particular biquotient are classified.


title:
Cabinet of curiosities: the interesting geometry of the angle {\beta} =
  arccos((3{\phi} - 1)/4)

abstract:
  In this paper we present the construction of several aggregates of
tetrahedra. Each construction is obtained by performing rotations on an initial
set of tetrahedra that either (1) contains gaps between adjacent tetrahedra, or
(2) exhibits an aperiodic nature. Following this rotation, gaps of the former
case are "closed" (in the sense that faces of adjacent tetrahedra are brought
into contact to form a "face junction") while translational and rotational
symmetries are obtained in the latter case. In all cases, an angular
displacement of {\beta} = arccos((3{\phi} - 1)/4) (or a closely related angle),
where {\phi} is the golden ratio, is observed between faces of a junction.
Additionally, the overall number of plane classes, defined as the number of
distinct facial orientations in the collection of tetrahedra, is reduced
following the transformation. Finally, we present several "curiosities"
involving the structures discussed here with the goal of inspiring the reader's
interest in constructions of this nature and their attending, interesting
properties.


title: Some algebraic identities for the alpha-permanent

abstract:
  We show that the permanent of a matrix is a linear combination of
determinants of block diagonal matrices which are simple functions of the
original matrix. To prove this, we first show a more general identity involving
\alpha-permanents: for arbitrary complex numbers \alpha and \beta, we show that
the \alpha-permanent of any matrix can be expressed as a linear combination of
\beta-permanents of related matrices. Some other identities for the
\alpha-permanent of sums and products of matrices are shown, as well as a
relationship between the \alpha-permanent and general immanants. We conclude
with a discussion of the computational complexity of the \alpha-permanent and
provide some numerical illustrations.


title:
Minimal surfaces in finite volume hyperbolic 3-manifolds N and in
  MxS(1), M a finite area hyperbolic surface

abstract:
  We consider properly immersed finite topology minimal surfaces S in complete
finite volume hyperbolic 3-manifolds N, and in M x S(1), where M is a complete
hyperbolic surface of finite area. We prove S has finite total curvature equal
to 2\pi times the Euler characteristic of S, and we describe the geometry of
the ends of S.


title: Brinicles as a case of inverse chemical gardens

abstract:
  Brinicles are hollow tubes of ice from centimetres to metres in length that
form under floating sea ice in the polar oceans when dense, cold brine drains
downwards from sea ice into sea water close to its freezing point. When this
extremely cold brine leaves the ice it freezes the water it comes into contact
with; a hollow tube of ice --- a brinicle --- growing downwards around the
plume of descending brine. We show that brinicles can be understood as a form
of the self-assembled tubular precipitation structures termed chemical gardens,
plant-like structures formed on placing together a soluble metal salt, often in
the form of a seed crystal, and an aqueous solution of one of many anions,
often silicate. On one hand, in the case of classical chemical gardens, an
osmotic pressure difference across a semipermeable precipitation membrane that
filters solutions by rejecting the solute leads to an inflow of water and to
its rupture. The internal solution, generally being lighter than the external
solution, flows up through the break, and as it does so a tube grows upwards by
precipitation around the jet of internal solution. Such chemical-garden tubes
can grow to many centimetres in length. In the case of brinicles, on the other
hand, in floating sea ice we have porous ice in a mushy layer that filters out
water, by freezing it, and allows concentrated brine through. Again there is an
osmotic pressure difference leading to a continuing ingress of sea water in a
siphon pump mechanism that is sustained as long as the ice continues to freeze.
Since the brine that is pumped out is denser than the sea water, and descends
rather rises, a brinicle is a downwards growing tube of ice; an inverse
chemical garden.


title:
Parameter estimation for compact binary coalescence signals with the
  first generation gravitational-wave detector network

abstract:
  Compact binary systems with neutron stars or black holes are one of the most
promising sources for ground-based gravitational wave detectors. Gravitational
radiation encodes rich information about source physics; thus parameter
estimation and model selection are crucial analysis steps for any detection
candidate events. Detailed models of the anticipated waveforms enable inference
on several parameters, such as component masses, spins, sky location and
distance that are essential for new astrophysical studies of these sources.
However, accurate measurements of these parameters and discrimination of models
describing the underlying physics are complicated by artifacts in the data,
uncertainties in the waveform models and in the calibration of the detectors.
Here we report such measurements on a selection of simulated signals added
either in hardware or software to the data collected by the two LIGO
instruments and the Virgo detector during their most recent joint science run,
including a "blind injection" where the signal was not initially revealed to
the collaboration. We exemplify the ability to extract information about the
source physics on signals that cover the neutron star and black hole parameter
space over the individual mass range 1 Msun - 25 Msun and the full range of
spin parameters. The cases reported in this study provide a snap-shot of the
status of parameter estimation in preparation for the operation of advanced
detectors.


title:
Local discrete velocity grids for deterministic rarefied flow
  simulations

abstract:
  Most of numerical methods for deterministic simulations of rarefied gas flows
use the discrete velocity (or discrete ordinate) approximation. In this
approach, the kinetic equation is approximated with a global velocity grid. The
grid must be large and fine enough to capture all the distribution functions,
which is very expensive for high speed flows (like in hypersonic aerodynamics).
In this article, we propose to use instead different velocity grids that are
local in time and space: these grids dynamically adapt to the width of the
distribution functions. The advantages and drawbacks of the method are
illustrated in several 1D test cases.


title: High-resolution x-ray analysis with multilayer gratings

abstract:
  Periodic multilayers are nowadays widely used to perform x-ray analysis in
the soft x-ray range (photon energy lower than 1 keV). However, they do not
permit to obtain high-resolution spectra like natural or synthetic crystals.
Thus, multilayers cannot resolve interferences between close x-ray lines. It
has been shown and demonstrated experimentally that patterning a grating
profile within a multilayer structure leads to a diffractive optics with
improved resolving power. We illustrate the use of a Mo/B4C multilayer grating
in the Fe L and C K spectral ranges, around 700 eV and 280 eV respectively.
First, in the Fe L range, the improved spectral resolution enables us to
distinguish the Fe L\alpha and L\beta emissions (separated by 13 eV). In
addition, using a sample made of a mix of LiF and an iron ore, we show that it
is possible to easily resolve the F K and Fe L emissions. These examples
demonstrate that an improved x-ray analysis can be obtained with multilayer
gratings when there is the need to study samples having elements giving rise to
close emission lines. Second, in the C K range, by comparing C K\alpha spectra
from B4C and cellulose, we show that the shape of the emission band is
sensitive to the chemical state of the carbon atom.


title:
Sampling from Dirichlet process mixture models with unknown
  concentration parameter: Mixing issues in large data implementations

abstract:
  We consider the question of Markov chain Monte Carlo sampling from a general
stick-breaking Dirichlet process mixture model, with concentration parameter
alpha. This paper introduces a Gibbs sampling algorithm that combines the slice
sampling approach of Walker (2007) and the retrospective sampling approach of
Papaspiliopoulos and Roberts (2008). Our general algorithm is implemented as
efficient open source C++ software, available as an R package, and is based on
a blocking strategy similar to that suggested by Papaspiliopoulos (2008) and
implemented by Yau et al (2011).
  We discuss the difficulties of achieving good mixing in MCMC samplers of this
nature and investigate sensitivity to initialisation. We additionally consider
the challenges when an additional layer of hierarchy is added such that joint
inference is to be made on alpha. We introduce a new label switching move and
compute the marginal model posterior to help to surmount these difficulties.
Our work is illustrated using a profile regression (Molitor et al, 2010)
application, where we demonstrate good mixing behaviour for both synthetic and
real examples.


title: Hitting time theorems for random matrices

abstract:
  Starting from an n-by-n matrix of zeros, choose uniformly random zero entries
and change them to ones, one-at-a-time, until the matrix becomes invertible. We
show that with probability tending to one as n tends to infinity, this occurs
at the very moment the last zero row or zero column disappears. We prove a
related result for random symmetric Bernoulli matrices, and give quantitative
bounds for some related problems. These results extend earlier work by Costello
and Vu [arXiv:math/0606414].


title: Equivalence of two definitions of the effective mass of a polaron

abstract:
  Two definitions of the effective mass of a particle interacting with a
quantum field, such as a polaron, are considered and shown to be equal in
models similar to the Froehlich polaron model. These are: 1. the mass defined
by the low momentum energy $E(P) \approx E(0)+P^2/2M$ of the translation
invariant system constrained to have momentum $P$ and 2. the mass $M$ of a
simple particle in an arbitrary slowly varying external potential, $V$,
described by the nonrelativistic Schroedinger equation, whose ground state
energy equals that of the combined particle/field system in a bound state in
the same $V$.


title:
Characterization of intra device mutual thermal coupling in multi finger
  SiGe:C HBTs

abstract:
  This paper studies the mutual coupling in trench isolated multi emitter
bipolar transistors fabricated in a Si/SiGe:C HBT technology STMicroelectronics
featuring fT and fmax of ~300GHz and ~400GHz, respectively. Thermal coupling
parameters are extracted using three dimensional (3D) thermal TCAD simulations.
The obtained parameters are implemented in a distributed transistor model that
considers self-heating as well as thermal coupling between emitter fingers.
Very good agreement is achieved between circuit simulations and DC measurements
carried out on an in house designed test structure.


title: Arbitrarily Large Residual Finiteness Growth

abstract:
  The residual finiteness growth of a group quantifies how well approximated
the group is by its finite quotients. In this paper, we construct groups with
arbitrarily large residual finiteness growth. We also demonstrate a new
relationship between residual finiteness growth and some decision problems in
groups, which we apply to our new groups.


title:
A convolution method for numerical solution of backward stochastic
  differential equations

abstract:
  We propose a new method for the numerical solution of backward stochastic
differential equations (BSDEs) which finds its roots in Fourier analysis. The
method consists of an Euler time discretization of the BSDE with certain
conditional expectations expressed in terms of Fourier transforms and computed
using the fast Fourier transform (FFT). The problem of error control is
addressed and a local error analysis is provided. We consider the extension of
the method to forward-backward stochastic differential equations (FBSDEs) and
reflected FBSDEs. Numerical examples are considered from finance demonstrating
the performance of the method.


title:
Triboelectric charging of volcanic ash from the 2011 Gr\'{i}msv\"{o}tn
  eruption

abstract:
  The plume from the 2011 eruption of Gr\'{i}msv\"{o}tn was highly electrically
charged, as shown by the considerable lightning activity measured by the UK Met
Office's low-frequency lightning detection network. Previous measurements of
volcanic plumes have shown that ash particles are electrically charged up to
hundreds of km away from the vent, which indicates that the ash continues to
charge in the plume [Harrison et al., Env. Res. Lett. 5 024004 (2010),
Hatakeyama J. Met. Soc. Japan 27 372 (1949)]. In this paper we study
triboelectric charging of different size fractions of a sample of volcanic ash
experimentally. Consistently with previous work, we find that the particle size
distribution is a determining factor in the charging. Specifically, our
laboratory experiments demonstrate that the normalised span of the particle
size distribution plays an important role in the magnitude of charging
generated. The influence of the normalised span on plume charging suggests that
all ash plumes are likely to be charged, with implications for remote sensing
and plume lifetime through scavenging effects.